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Chi, Lequan, Sultan Hameed, and Christopher L. P. Wolfe. "Comments on “Reconstruction of the Gulf Stream from 1940 to the Present and Correlation with the North Atlantic Oscillation”." Journal of Physical Oceanography 49, no. 10 (October 2019): 2731–34. http://dx.doi.org/10.1175/jpo-d-19-0096.1.
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AbstractThe path of the Gulf Stream as it leaves the continental shelf near Cape Hatteras is marked by a sharp gradient in ocean temperature known as the North Wall. The latitude location of the Gulf Stream North Wall (GSNW) has previously been estimated by subjective analysis of daily maps of sea surface temperatures. Recently, Watelet et al. (2017) presented an objective procedure by fitting an error function to the SST profile across the Gulf Stream at 81 longitude positions. The fit smooths over not only the GSNW but also the much colder waters from the Labrador Sea on the continental shelf. Watelet et al.’s procedure is therefore likely to misidentify the shelf-slope front as the Gulf Stream North Wall, leading to a systematic northward bias the in North Wall position.
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Phipps, R. M., and C. J. Tiltman. "The Babbage Field, Block 48/2a, UK North Sea." Geological Society, London, Memoirs 52, no. 1 (2020): 97–108. http://dx.doi.org/10.1144/m52-2019-1.
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AbstractThe Babbage gas field was discovered in 1988 by exploration well 48/2-2 which drilled into the Permian-age lower Leman Sandstone Formation below a salt wall. Seismic imaging is compromised by the presence of this salt wall, which runs east–west across the southern part of the structure, creating uncertainties in depth conversion and in the in-place volumes. Pre-stack depth migration with beam and reverse time migrations appropriate for the complex salt geometry provided an uplift in subsalt seismic imaging, enabling the development of the field, which is located at the northern edge of the main reservoir fairway in a mixed aeolian–fluvial setting. Advances in artificial fracturing technology were also critical to the development: in this area, deep burial is associated with the presence of pore-occluding clays, which reduce the reservoir permeability to sub-millidarcy levels. The Babbage Field was sanctioned in 2008, based on an in-place volume range of 248–582 bcf; first production was in 2010. It produces from five horizontal development wells that were artificially fracced to improve deliverability of gas from the tight matrix. None of the wells has drilled the gas–water contact, which remains a key uncertainty to the in-place volumes, along with depth-conversion uncertainty below the salt wall.
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Richter, David H., and Peter P. Sullivan. "The Sea Spray Contribution to Sensible Heat Flux." Journal of the Atmospheric Sciences 71, no. 2 (January 31, 2014): 640–54. http://dx.doi.org/10.1175/jas-d-13-0204.1.
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Abstract Direct numerical simulations (DNS) of turbulent Couette flow are combined with Lagrangian point-particle tracking to investigate the effects of a dispersed phase on bulk passive heat transport when the two phases can exchange both momentum and sensible heat. The idealized setup allows a fixed number of particles, without the influence of gravity, to be transported by carrier-phase motions across the mean velocity and temperature gradients that exist between the solid boundaries of turbulent Couette flow. In this way, the setup serves as a model of spray in a shear-dominated layer in the immediate vicinity of the water surface and provides insight into the ability of spray to enhance sensible heat fluxes. The authors find that the dispersed phase contributes a relatively large amount of vertical heat transport and increases the total heat flux across the domain by 25% or greater. Particles that accumulate in regions associated with wall-normal ejections efficiently carry heat across the channel. Furthermore, the authors find that the relative contribution of the dispersed-phase heat flux becomes larger with Reynolds number, suggesting an importance at atmospheric scales.
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Vanpachtenbeke, Michiel, Jan Van den Bulcke, Joris Van Acker, and Staf Roels. "Hygrothermal performance of timber frame walls with brick veneer cladding: a parameter analysis." E3S Web of Conferences 172 (2020): 07002. http://dx.doi.org/10.1051/e3sconf/202017207002.
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To meet the increasingly stringent energy efficiency requirements, the market share of timber frame houses is steadily growing across Europe. Timber frame walls in Belgium are typically combined with a brick veneer cladding, which has a high buffer capacity for wind driven rain and a relative low cavity ventilation rate. Consequently, moisture levels inside the cavity may become high, which might lead to an inward vapour flow and an elevated moisture content in the inner part of the wall. In combination with a moisture sensitive timber frame inner wall, this could result in an increased risk of fungal growth. Therefore, the aim of the current paper is to study the hygrothermal performance of timber frame walls with brick veneer cladding in a moderate sea climate. To do so, a field study on two typical timber frame walls with brick veneer cladding is conducted. The field study specifically focuses on the contradictory criterion for the vapour diffusion resistance of the wind barrier for summer and winter conditions. The data of the in-situ measuring campaign indicates that the differences between set-ups with wind barriers with different vapour diffusion resistance is rather limited. In addition, a parameter analysis is conducted using a numerical model. The parameter analysis indicates an increased mould growth risk due to the brick veneer cladding and the importance of providing hygroscopic moisture buffer capacity inside the wall.
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Schweppe, Gregor, Klaus-G. Hinzen, Sharon K. Reamer, and Shmuel Marco. "Reconstructing the slip velocities of the 1202 and 1759 CE earthquakes based on faulted archaeological structures at Tell Ateret, Dead Sea Fault." Journal of Seismology 25, no. 4 (June 3, 2021): 1021–42. http://dx.doi.org/10.1007/s10950-021-10009-0.
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AbstractArchaeological structures built across active faults and ruptured by earthquakes have been used as markers to measure the amount of displacement caused by ground motion and thus to estimate the magnitude of ancient earthquakes. The example used in this study is the Crusader fortress at Tel Ateret (Vadum Iacob) in the Jordan Gorge, north of the Sea of Galilee, a site which has been ruptured repeatedly since the Iron Age. We use detailed laser scans and discrete element models of the fortification walls to deduce the slip velocity during the earthquake. Further, we test whether the in-situ observed deformation pattern of the walls allows quantification of the amount both sides of the fault moved and whether post-seismic creep contributed to total displacement. The dynamic simulation of the reaction of the fortification wall to a variety of earthquake scenarios supports the hypothesis that the wall was ruptured by two earthquakes in 1202 and 1759 CE. For the first time, we can estimate the slip velocity during the earthquakes to 3 and 1 m/s for the two events, attribute the main motion to the Arabian plate with a mostly locked Sinai plate, and exclude significant creep contribution to the observed displacements of 1.25 and 0.5 m, respectively. Considering a minimum long-term slip rate at the site of 2.6 mm/year, there is a deficit of at least 1.6 m slip corresponding to a potential future magnitude 7.5 earthquake; if we assume ~5 mm/year geodetic rate, the deficit is even larger.
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Chambers, Iain. "Maritime Criticism and Theoretical Shipwrecks." PMLA/Publications of the Modern Language Association of America 125, no. 3 (May 2010): 678–84. http://dx.doi.org/10.1632/pmla.2010.125.3.678.
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All visible objects, man, are but as pasteboard masks. But in each event—in the living act, the undoubted deed—there, some unknown but still reasoning thing puts forth the mouldings of its features from behind the unreasoning mask. If man will strike, strike through the mask! How can the prisoner reach outside except by thrusting through the wall? To me, the white whale is that wall, shoved near to me. Sometimes I think there's naught beyond. But 'tis enough.—Herman Melville, Moby-Dick; or, The WhaleFamiliar Landscapes are Today Challenged by Illicit Sea Journeys. The Southern Shores of Occidental Modernity are beached by the uninvited guest, by the arrival of histories and cultures that exceed its desires and augment its fears. Like a nemesis from the sea, the interrogative presence of the migrant, who announces planetary processes that are not ours to manage and define, draws Europe and the rest of the West to the threshold of a modernity that exceeds itself. In Isaac Julien's video installation Western Union: Small Boats (2007), the cruel passage of northward migration—across the inhospitable desert and perilous sea—proposes a dramatic poetics that seeks to force apart the conclusive framings of existing political, cultural, and historical narratives. Contorted black bodies gasping in the foam, abandoned on the beach in silver body bags among the sunbathers or writhing on the palace floors of European hierarchies replay the black Atlantic, memories of slavery, and racial oppression in the modern-day Mediterranean.
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Hauschild, K., W. M. Weber, W. Clauss, and M. K. Grieshaber. "Excretion of thiosulphate, the main detoxification product of sulphide, by the lugworm arenicola marina L." Journal of Experimental Biology 202, no. 7 (April 1, 1999): 855–66. http://dx.doi.org/10.1242/jeb.202.7.855.
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Thiosulphate, the main sulphide detoxification product, is accumulated in the body fluids of the lugworm Arenicola marina. The aim of this study was to elucidate the fate of thiosulphate. Electrophysiological measurements revealed that the transepithelial resistance of body wall sections was 76+/−34 capomega cm2 (mean +/− s.d., N=14), indicating that the body wall of the lugworm is a leaky tissue in which mainly paracellular transport along cell junctions takes place. The body wall was equally permeable from both sides to thiosulphate, the permeability coefficient of which was 1. 31×10(−)3+/−0.37×10(−)3 cm h-1 (mean +/− s.d., N=30). No evidence was found for a significant contribution of the gills or the nephridia to thiosulphate permeation. Thiosulphate flux followed the concentration gradient, showing a linear correlation (r=0.997) between permeated and supplied (10–100 mmol l-1) thiosulphate. The permeability of thiosulphate was not sensitive to the presence of various metabolic inhibitors, implicating a permeation process independent of membrane proteins and showing that the lugworm does not need to use energy to dispose of the sulphide detoxification product. The present data suggest a passive permeation of thiosulphate across the body wall of A. marina. In live lugworms, thiosulphate levels in the coelomic fluid and body wall tissue decreased slowly and at similar rates during recovery from sulphide exposure. The decline in thiosulphate levels followed a decreasing double-exponential function. Thiosulphate was not further oxidized to sulphite or sulphate but was excreted into the sea water.
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McGiveron, Rafeeq O. "From a “Stretch of Grey Sea” to the “Extent of Space”: The Gaze Across Vistas in Cather’s The Professor’s House." Western American Literature 34, no. 4 (2000): 389–408. http://dx.doi.org/10.1353/wal.2000.0002.
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Julian, D., F. Gaill, E. Wood, A. J. Arp, and C. R. Fisher. "Roots as a site of hydrogen sulfide uptake in the hydrocarbon seep vestimentiferan Lamellibrachia sp." Journal of Experimental Biology 202, no. 17 (September 1, 1999): 2245–57. http://dx.doi.org/10.1242/jeb.202.17.2245.
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Vestimentiferan tubeworms have no mouth or gut, and the majority of their nutritional requirements are provided by endosymbiotic bacteria that utilize hydrogen sulfide oxidation to fix CO(2) into organic molecules. It has been assumed that all vestimentiferans obtain the sulfide, O(2) and CO(2) needed by the bacteria across the plume (gill) surface, but some live in locations where very little sulfide is available in the sea water surrounding the plume. We propose that at least some of these vestimentiferans can grow a posterior extension of their body and tube down into the sea-floor sediment, and that they can use this extension, which we call the ‘root’, to take up sulfide directly from the interstitial water. In this study of the vestimentiferan Lamellibrachia sp., found at hydrocarbon seeps in the Gulf of Mexico at depths of approximately 700 m, we measured seawater and interstitial sulfide concentrations in the hydrocarbon seep habitat, determined the structural characteristics of the root tube using transmission electron microscopy, characterized the biochemical composition of the tube wall, and measured the sulfide permeability of the root tube. We found that, while the sulfide concentration is less than 1 (μ)mol l(−)(1) in the sea water surrounding the gills, it can be over 1.5 mmol l(−)(1) at a depth of 10–25 cm in sediment beneath tubeworm bushes. The root tube is composed primarily of giant (β)-chitin crystallites (12–30 % of total mass) embedded in a protein matrix (50 % of total mass). Root tubes have a mean diameter of 1.4 mm, a mean wall thickness of 70 (μ)m and can be over 20 cm long. The tubeworm itself typically extends its body to the distal tip of the root tube. The root tube wall was quite permeable to sulfide, having a permeability coefficient at 20 degrees C of 0. 41×10(−)(3)cm s(−)(1), with root tube being 2.5 times more permeable to sulfide than trunk tube of the same diameter. The characteristics of the root suggest that it reaches down to the higher sulfide levels present in the deeper sediment and that it functions to increase the surface area available for sulfide uptake in a manner analogous to a respiratory organ.
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Stewart, Simon A. "Detachment-controlled triangle zones in extension and inversion tectonics." Interpretation 2, no. 4 (November 1, 2014): SM29—SM38. http://dx.doi.org/10.1190/int-2014-0026.1.
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“Triangle zone” geometry is well established in thrust tectonics, where the leading edge of a frontal thrust branches backward onto a hinterland-directed roof thrust, and the triangle zone thus formed defines the thrust system’s leading edge. Similar geometries occur in extension and inversion settings, where a triangle zone can form between a deep-seated master fault and a roof fault or backthrust located in a hanging-wall detachment. In basement-controlled extension, triangle zone development can occur when the shear strength of the master fault plane in the zone above a hanging-wall detachment cutoff exceeds that of a new or reactivated antithetic fault detaching on the hanging-wall dip slope. This structural style is characterized by pronounced hanging-wall synclines linked to detached extensional faults higher up the hanging-wall dip slopes. The same principles apply during early phases of inversion tectonics. The part of the master fault that is above the hanging-wall detachment cutoff may constitute a buttress that causes displacement to backthrust along any available detachment into accommodation structures such as emergent ramps. This structural style is characterized by compressional structures within the graben while there is minor or even no sign of inversion on the graben margin faults. These geometries could be accounted for by other processes, for example, localized deep-seated fault-controlled structures within graben, or salt redistribution. However, fieldwork and analog models demonstrate the admissibility of triangle zone kinematics across a range of tectonic settings in the presence of detachment layers that are thin relative to the overall stratigraphy — typically tens to hundreds of meters in thickness. These models can guide seismic interpretation of unusual fold structures in extensional and inverted graben. Seismic interpretation examples were evaluated from the North Sea and Saudi Arabia.
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Jordan, Lori C., and Michael R. DeBaun. "Cerebral hemodynamic assessment and neuroimaging across the lifespan in sickle cell disease." Journal of Cerebral Blood Flow & Metabolism 38, no. 9 (April 18, 2017): 1438–48. http://dx.doi.org/10.1177/0271678x17701763.
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Children and adults with sickle cell anemia (SCA) have a higher risk of strokes compared to age- and race-matched peers. Velocity in the middle cerebral or distal internal carotid artery as measured by transcranial Doppler ultrasound is a recognized method to identify children but not adults with SCA at high-risk for first stroke. For both children and adults with SCA that have had a stroke, no methods clearly identify individuals at highest risk of recurrent strokes or an initial silent stroke, the most common neurological injury. Methods to assess cerebral hemodynamics in SCA have been utilized for decades but often required radiotracers making them not feasible for screening and longitudinal follow-up. MRI approaches that do not require exogenous contrast have been introduced and are appealing in both clinical and research scenarios. Improved neuroimaging strategies hold promise for identifying individuals with SCA at increased risk of initial and recurrent infarcts, justifying more aggressive risk-based therapy. We review the epidemiology of stroke in SCA, the impact of strokes, stroke mechanisms, and potential imaging strategies including regional and global oxygen extraction fraction, cerebral blood flow, and vessel wall imaging to identify individuals at high-risk of stroke.
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Hong, Leexan, Tricia Elbl, James Ward, Clara Franzini-Armstrong, Krystyna K. Rybicka, Beth K. Gatewood, David L. Baillie, and Elizabeth A. Bucher. "MUP-4 is a novel transmembrane protein with functions in epithelial cell adhesion in Caenorhabditis elegans." Journal of Cell Biology 154, no. 2 (July 23, 2001): 403–14. http://dx.doi.org/10.1083/jcb.200007075.
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Tissue functions and mechanical coupling of cells must be integrated throughout development. A striking example of this coupling is the interactions of body wall muscle and hypodermal cells in Caenorhabditis elegans. These tissues are intimately associated in development and their interactions generate structures that provide a continuous mechanical link to transmit muscle forces across the hypodermis to the cuticle. Previously, we established that mup-4 is essential in embryonic epithelial (hypodermal) morphogenesis and maintenance of muscle position. Here, we report that mup-4 encodes a novel transmembrane protein that is required for attachments between the apical epithelial surface and the cuticular matrix. Its extracellular domain includes epidermal growth factor-like repeats, a von Willebrand factor A domain, and two sea urchin enterokinase modules. Its intracellular domain is homologous to filaggrin, an intermediate filament (IF)-associated protein that regulates IF compaction and that has not previously been reported as part of a junctional complex. MUP-4 colocalizes with epithelial hemidesmosomes overlying body wall muscles, beginning at the time of embryonic cuticle maturation, as well as with other sites of mechanical coupling. These findings support that MUP-4 is a junctional protein that functions in IF tethering, cell–matrix adherence, and mechanical coupling of tissues.
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Kuijt, Ian, Bill Finlayson, and Jode MacKay. "Pottery Neolithic landscape modification at Dhra'." Antiquity 81, no. 311 (March 1, 2007): 106–18. http://dx.doi.org/10.1017/s0003598x00094874.
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This report of the discovery of low walls running across the slopes east of the Dead Sea presents an important landmark in the history of farming, for these were terrace walls put in place to conserve soil and control water around 6000 cal BC. The authors point to some of the implications of what they see as early landscape modification at the scale of a small community or household.
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Duxbury, S. "Two new Early Cretaceous dinocyst species from the Central North Sea Basin." Journal of Micropalaeontology 21, no. 1 (May 1, 2002): 75–80. http://dx.doi.org/10.1144/jm.21.1.75.
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Abstract. Two new species of dinocyst, Cerbia monilis and Hapsocysta susanae are described from the Lower Cretaceous of the Central North Sea Basin. The first ranges across the Aptian/Albian boundary and the latter is restricted to the Early to Middle Albian interval; both are valuable index taxa in this area. Hapsocysta susanae is remarkably similar to cysts ‘without walls’ described from the Late Oligocene and Early Miocene, and detailed comparisons are made. The ranges of the two species described here are illustrated against regional lithostratigraphic and biostratigraphic schemes.
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Wilt, F. H. "Determination and morphogenesis in the sea urchin embryo." Development 100, no. 4 (August 1, 1987): 559–76. http://dx.doi.org/10.1242/dev.100.4.559.
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The study of the sea urchin embryo has contributed importantly to our ideas about embryogenesis. This essay re-examines some issues where the concerns of classical experimental embryology and cell and molecular biology converge. The sea urchin egg has an inherent animal-vegetal polarity. An egg fragment that contains both animal and vegetal material will produce a fairly normal larva. However, it is not clear to what extent the oral-aboral axis is specified in embryos developing from meridional fragments. Newly available markers of the oral-aboral axis allow this issue to be settled. When equatorial halves, in which animal and vegetal hemispheres are separated, are allowed to develop, the animal half forms a ciliated hollow ball. The vegetal half, however, often forms a complete embryo. This result is not in accord with the double gradient model of animal and vegetal characteristics that has been used to interpret almost all defect, isolation and transplantation experiments using sea urchin embryos. The effects of agents used to animalize and vegetalize embryos are also due for re-examination. The classical animalizing agent, Zn2+, causes developmental arrest, not expression of animal characters. On the other hand, Li+, a vegetalizing agent, probably changes the determination of animal cells. The stability of these early determinative steps may be examined in dissociation-reaggregation experiments, but this technique has not been exploited extensively. The morphogenetic movements of primary mesenchyme are complex and involve a number of interactions. It is curious that primary mesenchyme is dispensable in skeleton formation since in embryos devoid of primary mesenchyme, the secondary mesenchyme cells will form skeletal elements. It is likely that during its differentiation the primary mesenchyme provides some of its own extracellular microenvironment in the form of collagen and proteoglycans. The detailed form of spicules made by primary mesenchyme is determined by cooperation between the epithelial body wall, the extracellular material and the inherent properties of primary mesenchyme cells. Gastrulation in sea urchins is a two-step process. The first invagination is a buckling, the mechanism of which is not understood. The secondary phase in which the archenteron elongates across the blastocoel is probably driven primarily by active cell repacking. The extracellular matrix is important for this repacking to occur, but the basis of the cellular-environmental interaction is not understood.(ABSTRACT TRUNCATED AT 400 WORDS)
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Abueladas, AbdEl-Rahman, and Emad Akawwi. "Ground-penetrating radar inspection of subsurface historical structures at the baptism (El-Maghtas) site, Jordan." Geoscientific Instrumentation, Methods and Data Systems 9, no. 2 (December 22, 2020): 491–97. http://dx.doi.org/10.5194/gi-9-491-2020.
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Abstract. The baptism (El-Maghtas) site is located to the north of the Dead Sea on the eastern bank of the Jordan River. Previous archeological excavations in the surrounding area have uncovered artifacts that include the location that was home to “John the Baptist”, who lived and preached in the early 1st Century AD and is known for baptizing Jesus. Archeological excavations have revealed walls, antiquities, and ancient water systems that include conduits, pools, and ancient pottery pipes. A ground-penetrating radar (GPR) survey was carried out at select locations along parallel profiles using a subsurface interface radar system (Geophysical Survey Systems Inc. SIRvoyer-20) with 400 MHz or 900 MHz mono-static shielded antennas in order to locate archeological materials at shallow depths. The GPR profiles revealed multiple subsurface anomalies across the study area. At the John the Baptist Church site a buried wall was detected along the profiles, and at the pool site the survey delineated several buried channels. GPR data also confirmed the extension of an ancient pottery pipe at the Elijah's Hill site through the production of a clear diffraction hyperbola anomaly related to the ancient pottery pipe that could be discriminated from the 2D profiles. The GPR data were displaced using 3D imaging to define the horizontal and vertical extent of the pipe.
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Trower, Shelley. "ON THE CLIFF EDGE OF ENGLAND: TOURISM AND IMPERIAL GOTHIC IN CORNWALL." Victorian Literature and Culture 40, no. 1 (March 2012): 199–214. http://dx.doi.org/10.1017/s1060150311000313.
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The final chapters of Bram Stoker's novel The Jewel of Seven Stars (1903) are set in a house on the “very verge” of a cliff in Cornwall, the peninsula located at the far south west of England. The narrator, Malcolm Ross, travels overnight from London to Cornwall, then describes his first sight of the house, and a little later the position of the dining-room, its walls hanging over the sea: We were all impressed by the house as it appeared in the bright moonlight. A great grey stone mansion of the Jacobean period; vast and spacious, standing high over the sea on the very verge of a high cliff. When we had swept round the curve of the avenue cut through the rock, and come out on the high plateau on which the house stood, the crash and murmur of waves breaking against rock far below us came with an invigorating breath of moist sea air . . .We had supper in the great dining-room on the south side, the walls of which actually hung over the sea. The murmur came up muffled, but it never ceased. As the little promontory stood well out into the sea, the northern side of the house was open; and the due north was in no way shut out by the great mass of rock, which, reared high above us, shut out the rest of the world. Far off across the bay we could see the trembling lights of the castle, and here and there along the shore the faint light of a fisher's window. For the rest the sea was a dark blue plain with here and there a flicker of light as the gleam of starlight fell on the slope of a swelling wave. (195–96; ch. 17) In this liminal place, there is a confusion of categories: the sea not only crosses the boundary into land (the sound of its “murmur” and its moistness in the air) but seems itself to become land (a “dark blue plain”). The actual land is in contrast invisible from the house, being shut out by a mass of rock that rears high above. From the far distant shore, on the other side of the bay, the lights vibrate across both land and sea, further collapsing the sense of a distinction between them: from the “trembling lights” of the castle to the intermittent “flicker of light” on the waves.
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Díaz, D., A. Maksymowicz, G. Vargas, E. Vera, E. Contreras-Reyes, and S. Rebolledo. "Exploring the shallow structure of the San Ramón thrust fault in Santiago, Chile (∼33.5° S), using active seismic and electric methods." Solid Earth Discussions 6, no. 1 (January 28, 2014): 339–75. http://dx.doi.org/10.5194/sed-6-339-2014.
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Abstract. The crustal-scale west-vergent San Ramón thrust fault system at the foot of the main Andean Cordillera in central Chile is a geologically active structure with Quaternary manifestations of complex surface rupture along fault segments in the eastern border of Santiago city. From the comparison of geophysical and geological observations, we assessed the subsurface structure pattern affecting sedimentary cover and rock-substratum topography across fault scarps, which is critic for evaluating structural modeling and associated seismic hazard along this kind of faults. We performed seismic profiles with an average length of 250 m, using an array of twenty-four geophones (GEODE), and 25 shots per profile, supporting high-resolution seismic tomography for interpreting impedance changes associated to deformed sedimentary cover. The recorded traveltime refractions and reflections were jointly inverted by using a 2-D tomographic approach, which resulted in variations across the scarp axis in both velocities and reflections interpreted as the sedimentary cover-rock substratum topography. Seismic anisotropy observed from tomographic profiles is consistent with sediment deformation triggered by west-vergent thrust tectonics along the fault. Electrical soundings crossing two fault scarps supported subsurface resistivity tomographic profiles, which revealed systematic differences between lower resistivity values in the hanging wall with respect to the footwall of the geological structure, clearly limited by well-defined east-dipping resistivity boundaries. The latter can be interpreted in terms of structurally driven fluid content-change between the hanging wall and the footwall of a permeability boundary associated with the San Ramón fault. The overall results are consistent with a west-vergent thrust structure dipping ∼55° E at subsurface levels in piedmont sediments, with local complexities being probably associated to fault surface rupture propagation, fault-splay and fault segment transfer zones.
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Odunitan-Wayas, Feyisayo, Kufre Okop, Robert Dover, Olufunke Alaba, Lisa Micklesfield, Thandi Puoane, Monica Uys, et al. "Food Purchasing Characteristics and Perceptions of Neighborhood Food Environment of South Africans Living in Low-, Middle- and High-Socioeconomic Neighborhoods." Sustainability 10, no. 12 (December 16, 2018): 4801. http://dx.doi.org/10.3390/su10124801.
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Using intercept surveys, we explored demographic and socioeconomic factors associated with food purchasing characteristics of supermarket shoppers and the perceptions of their neighborhood food environment in urban Cape Town. Shoppers (N = 422) aged ≥18 years, categorized by their residential socioeconomic areas (SEAs), participated in a survey after shopping in supermarkets located in different SEAs. A subpopulation, out-shoppers (persons shopping outside their residential SEA), and in-shoppers (persons residing and shopping in the same residential area) were also explored. Fruits and vegetables (F&V) were more likely to be perceived to be of poor quality and healthy food not too expensive by shoppers from low- (OR = 6.36, 95% CI = 2.69, 15.03, p < 0.0001), middle-SEAs (OR = 3.42, 95% CI = 1.45, 8.04, p < 0.001) compared to the high-SEA shoppers. Low SEA shoppers bought F&V less frequently than high- and middle-SEA shoppers. Purchase of sugar-sweetened beverages (SSBs) and snacks were frequent and similar across SEAs. Food quality was important to out-shoppers who were less likely to walk to shop, more likely to be employed and perceived the quality of F&V in their neighborhood to be poor. Food purchasing characteristics are influenced by SEAs, with lack of mobility and food choice key issues for low-SEA shoppers.
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Pownall, J. M., R. Hall, and I. M. Watkinson. "Extreme extension across Seram and Ambon, eastern Indonesia: Evidence for Banda slab rollback." Solid Earth Discussions 5, no. 1 (April 17, 2013): 525–607. http://dx.doi.org/10.5194/sed-5-525-2013.
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Abstract. The island of Seram, which lies in the northern part of the 180°-curved Banda Arc, has previously been interpreted as a fold-and-thrust belt formed during arc-continent collision, which incorporates ophiolites intruded by granites thought to have been produced by anatexis within a metamorphic "sole". However, new geological mapping and a re-examination of the field relations cause us to question this model. We instead propose that there is evidence for recent N–S extension that has caused the high-temperature exhumation of hot mantle peridotites, granites, and granulites (the "Kobipoto Complex") beneath low-angle lithospheric detachment faults. Greenschist- to lower-amphibolite facies metapelites and amphibolites of the Tehoru Formation, which comprise the hanging wall above the detachment faults, were overprinted by sillimanite-grade metamorphism, migmatisation and limited localised diatexis to form the Taunusa Complex. Highly aluminous metapelitic garnet + cordierite + sillimanite + spinel + corundum + quartz granulites exposed in the Kobipoto Mountains (central Seram) are intimately associated with the peridotites. Spinel + quartz inclusions in garnet, which indicate that peak metamorphic temperatures for the granulites likely approached 900 °C, confirm that peridotite was juxtaposed against the crust at typical lithospheric mantle temperatures and could not have been part of a cooled ophiolite. Some granulites experienced slight metatexis, but the majority underwent more advanced in situ anatexis to produce widespread granitic diatexites characterised by abundant cordierite and garnet xenocrysts and numerous restitic sillimanite + spinel "clots". These Mio-Pliocene "cordierite granites", which are present throughout Ambon, western Seram, and the Kobipoto Mountains in direct association with peridotites, demonstrate that the extreme extension required to have driven Kobipoto Complex exhumation must have occurred along much of the northern Banda Arc. In central Seram, smeared lenses of peridotites are incorporated with a major left-lateral strike-slip shear zone (the "Kawa Shear Zone"), demonstrating that strike-slip motions likely initiated shortly after the mantle had been partly exhumed by detachment faulting and that the main strike-slip faults may themselves be reactivated and steepened low-angle detachments. The Kobipoto Mountains represent a left-lateral pop-up structure that has facilitated the final stages of exhumation of the high-grade Kobipoto Complex through overlying Mesozoic sedimentary rocks. On Ambon, Quaternary "ambonites" (cordierite + garnet dacites) are evidently the volcanic equivalent of the cordierite granites as they also contain granulite-inherited xenoliths and xenocrysts. The geodynamic driver for mantle exhumation along the detachment faults and strike-slip faulting in central Seram is very likely the same – we interpret the extreme extension to be the result of eastward slab rollback into the Banda Embayment as outlined by the latest plate reconstructions for Banda Arc evolution.
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Leary, P. N., and D. S. Wray. "The Foraminiferal assemblages across three middle Turonian marl bands and a note on their genesis." Journal of Micropalaeontology 8, no. 2 (December 1, 1989): 143–48. http://dx.doi.org/10.1144/jm.8.2.143.
Full textAbstract:
Abstract. the changes in the Foraminiferal assemblage across three Middle Turonian marl bands show a consistent pattern, with (a) very similar gross assemblage characteristics from the white chalk below and above the marls containing an approximately 60:40% planktonic:benthonic ratio, greater than 50% non-keeled morphotypes (within the planktonic assemblage) and with infaunal and epifaunal groups well represented but (b) from within the marls the assemblage is dominated by benthonics (30:70% p:b ratio), less than 20% non-keeled morphotypes (within the planktonic assemblage) and a benthonic assemblage dominated by the infaunal groups. Although there is evidence of some dissolution within the marls, with the pitting of the thinner test walls, we propose the changes in the assemblage are not due to large scale post mortem diagenetic process. But are most likely due to environmental changes within the chalk sea, possibly caused by the ephemeral introduction into the surface waters of volcanic ash.
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Winsnes, Selena Axelrod. "There Is a House on Castle Drive: The Story of Wulff Joseph Wulff." History in Africa 27 (January 2000): 443–48. http://dx.doi.org/10.2307/3172125.
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You are in Osu, Accra. As you walk along Castle Drive toward Christiansborg Castle, there is row of four houses on your left and a large open field on your right. The field, with the grass carefully tended, is the locus of the old Danish cemetery, where the gravestones that remained have been mounted into a low wall built on the sea side of the field. Across the street, one of the houses, the second one from your starting point, has a stone name plate over the main door bearing the inscription: FREDERICHS MINDE 1840 W.I.WULFF. Scandinavians who have visited Ghana know about this house. They know that it was built by a Danish civil servant who had worked for the Danish Board of Trade, that he had established a family there, and they may know that he died of illness there at the age of thirty-three. They also know that by simply going to the door and knocking they will be welcomed and permitted to look around.The residents of the house—and indeed it is a residence—who so graciously receive unexpected and unannounced visitors, are at present members of the Wulff-Cochrane family. When I was last there it was Mr. and Mrs. Leslie Wulff-Cochrane who opened the doors to me and my three friends. We were shown around the house, treated to the fine view of the ocean from the living room, and then taken down into the basement to see the singular element of the house, the grave of Wulff J. Wulff.
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Bercher, Mark, Jim Wahl, Bruce E. Vogel, Charles Lu, Edward M. Hedgecock, David H. Hall, and John D. Plenefisch. "mua-3, a gene required for mechanical tissue integrity in Caenorhabditis elegans, encodes a novel transmembrane protein of epithelial attachment complexes." Journal of Cell Biology 154, no. 2 (July 23, 2001): 415–26. http://dx.doi.org/10.1083/jcb.200103035.
Full textAbstract:
Normal locomotion of the nematode Caenorhabditis elegans requires transmission of contractile force through a series of mechanical linkages from the myofibrillar lattice of the body wall muscles, across an intervening extracellular matrix and epithelium (the hypodermis) to the cuticle. Mutations in mua-3 cause a separation of the hypodermis from the cuticle, suggesting this gene is required for maintaining hypodermal–cuticle attachment as the animal grows in size postembryonically. mua-3 encodes a predicted 3,767 amino acid protein with a large extracellular domain, a single transmembrane helix, and a smaller cytoplasmic domain. The extracellular domain contains four distinct protein modules: 5 low density lipoprotein type A, 52 epidermal growth factor, 1 von Willebrand factor A, and 2 sea urchin-enterokinase-agrin modules. MUA-3 localizes to the hypodermal hemidesmosomes and to other sites of mechanically robust transepithelial attachments, including the rectum, vulva, mechanosensory neurons, and excretory duct/pore. In addition, it is shown that MUA-3 colocalizes with cytoplasmic intermediate filaments (IFs) at these sites. Thus, MUA-3 appears to be a protein that links the IF cytoskeleton of nematode epithelia to the cuticle at sites of mechanical stress.
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SIDDIQUI, M. H. KAMRAN, and MARK R. LOEWEN. "Characteristics of the wind drift layer and microscale breaking waves." Journal of Fluid Mechanics 573 (February 2007): 417–56. http://dx.doi.org/10.1017/s0022112006003892.
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An experimental study, investigating the mean flow and turbulence in the wind drift layer formed beneath short wind waves was conducted. The degree to which these flows resemble the flows that occur in boundary layers adjacent to solid walls (i.e. wall-layers) was examined. Simultaneous DPIV (digital particle image velocimetry) and infrared imagery were used to investigate these near-surface flows at a fetch of 5.5 m and wind speeds from 4.5 to 11 m s−1. These conditions produced short steep waves with dominant wavelengths from 6 cm to 18 cm. The mean velocity profiles in the wind drift layer were found to be logarithmic and the flow was hydrodynamically smooth at all wind speeds. The rate of dissipation of turbulent kinetic energy was determined to be significantly greater in magnitude than would occur in a comparable wall-layer. Microscale breaking waves were detected using the DPIV data and the characteristics of breaking and non-breaking waves were compared. The percentage of microscale breaking waves increased abruptly from 11% to 80% as the wind speed increased from 4.5 to 7.4 m s− and then gradually increased to 90% as the wind speed increased to 11 m s−. At a depth of 1 mm, the rate of dissipation was 1.7 to 3.2 times greater beneath microscale breaking waves compared to non-breaking waves. In the crest–trough region beneath microscale breaking waves, 40% to 50% of the dissipation was associated with wave breaking. These results demonstrated that the enhanced near-surface turbulence in the wind drift layer was the result of microscale wave breaking. It was determined that the rate of dissipation of turbulent kinetic energy due to wave breaking is a function of depth, friction velocity, wave height and phase speed as proposed by Terray et al. (1996). Vertical profiles of the rate of dissipation showed that beneath microscale breaking waves there were two distinct layers. Immediately beneath the surface, the dissipation decayed as ζ−0.7 and below this in the second layer it decayed as ζ−2. The enhanced turbulence associated with microscale wave breaking was found to extend to a depth of approximately one significant wave height. The only similarity between the flows in these wind drift layers and wall-layers is that in both cases the mean velocity profiles are logarithmic. The fact that microscale breaking waves were responsible for 40%–50% of the near-surface turbulence supports the premise that microscale breaking waves play a significant role in enhancing the transfer of gas and heat across the air–sea interface.
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Li, Liang, Matthew Thomas Wayland, Hui-Xia Chen, and Yue Yang. "Remarkable morphological variation in the proboscis of Neorhadinorhynchus nudus (Harada, 1938) (Acanthocephala: Echinorhynchida)." Parasitology 146, no. 3 (September 27, 2018): 348–55. http://dx.doi.org/10.1017/s003118201800166x.
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AbstractThe acanthocephalans are characterized by a retractible proboscis, armed with rows of recurved hooks, which serves as the primary organ for attachment of the adult worm to the intestinal wall of the vertebrate definitive host. Whilst there is a considerable variation in the size, shape and armature of the proboscis across the phylum, intraspecific variation is generally regarded to be minimal. Consequently, subtle differences in proboscis morphology are often used to delimit congeneric species. In this study, striking variability in proboscis morphology was observed among individuals of Neorhadinorhynchus nudus (Harada, 1938) collected from the frigate tuna Auxis thazard Lacépède (Perciformes: Scombridae) in the South China Sea. Based on the length of the proboscis, and number of hooks per longitudinal row, these specimens of N. nudus were readily grouped into three distinct morphotypes, which might be considered separate taxa under the morphospecies concept. However, analysis of nuclear and mitochondrial DNA sequences revealed a level of nucleotide divergence typical of an intraspecific comparison. Moreover, the three morphotypes do not represent three separate genetic lineages. The surprising, and previously undocumented level of intraspecific variation in proboscis morphology found in the present study, underscores the need to use molecular markers for delimiting acanthocephalan species.
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White, William A. "More on Deep Glacial Erosion by Continental Ice Sheets and Their Tongues of Distributary Ice." Quaternary Research 30, no. 2 (September 1988): 137–50. http://dx.doi.org/10.1016/0033-5894(88)90019-1.
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High latitude intracontinental seaways occupy great troughs carved by broad tongues of inland ice as it debouched to deep marine water. Such troughs occur in glaciated coasts, but not in stable, nonglaciated ones. Where ice flowed along the walls of troughs whose adjacent uplands held local glaciers, the walls simulate alpine troughs with faceted spurs and submarine hanging tributary valleys. Where uplands were not glaciated, trough walls are unbreached. Where ice flowed across them, coasts are digitate in low relief. In the northeastern sector of the Laurentide Ice Sheet, large glacial grooves converge toward the Gulf of Boothia-Prince Regent Inlet-Lancaster Sound avenue of egress to open sea, suggesting that it was an exit for inland ice which shaped it to its present form. The subduction Pacific coast of the Americas is mostly harborless in nonglaciated latitudes, but in southern Chile and British Columbia it is dissected. A circular gravity high 2800 km across is concentric with the area covered by the Laurentide Ice Sheet. Abyssal glacial silts are voluminous enough to account for an average of 100–150 m of erosion over the area covered by the Laurentide Ice Sheet.
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Bailey, Liam D., Bruno J. Ens, Christiaan Both, Dik Heg, Kees Oosterbeek, and Martijn van de Pol. "No phenotypic plasticity in nest-site selection in response to extreme flooding events." Philosophical Transactions of the Royal Society B: Biological Sciences 372, no. 1723 (May 8, 2017): 20160139. http://dx.doi.org/10.1098/rstb.2016.0139.
Full textAbstract:
Phenotypic plasticity is a crucial mechanism for responding to changes in climatic means, yet we know little about its role in responding to extreme climatic events (ECEs). ECEs may lack the reliable cues necessary for phenotypic plasticity to evolve; however, this has not been empirically tested. We investigated whether behavioural plasticity in nest-site selection allows a long-lived shorebird ( Haematopus ostralegus ) to respond to flooding. We collected longitudinal nest elevation data on individuals over two decades, during which time flooding events have become increasingly frequent. We found no evidence that individuals learn from flooding experiences, showing nest elevation change consistent with random nest-site selection. There was also no evidence of phenotypic plasticity in response to potential environmental cues (lunar nodal cycle and water height). A small number of individuals, those nesting near an artificial sea wall, did show an increase in nest elevation over time; however, there is no conclusive evidence this occurred in response to ECEs. Our study population showed no behavioural plasticity in response to changing ECE patterns. More research is needed to determine whether this pattern is consistent across species and types of ECEs. If so, ECEs may pose a major challenge to the resilience of wild populations. This article is part of the themed issue ‘Behavioural, ecological and evolutionary responses to extreme climatic events’.
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HOLLIDAY, CHARLES W., DAVID B. ROYE, and ROBERT D. ROER. "Salinity-induced Changes in Branchial Na+/K+- ATPase Activity and Transepithelial Potential Difference in the Brine Shrimp Artemia Sauna." Journal of Experimental Biology 151, no. 1 (July 1, 1990): 279–96. http://dx.doi.org/10.1242/jeb.151.1.279.
Full textAbstract:
Silver staining of the adult brine shrimp, Artemia salina, revealed that only the metepipodites of the phyllopodia were significantly permeable to chloride and/or silver ions. The metepipodites stained in a reticulated pattern, possibly indicating areas in the cuticle over cells specialized for chloride secretion. Crude homogenates of metepipodites had very high Na+/K+-ATPase enzyme specific activity (ESA) which increased in proportion to the salinity of the external medium and, thus, in proportion to the need for outward salt transport in these strongly hypoosmoregulating animals. Metepipodite ESA as a percentage of whole-body ESA increased from 7.6% in 50% sea water (SW) to 25.0% in 400%SW. Gut and maxillary gland also had high Na+/K+-ATPase ESAs, implicating these organs in osmoregulatory processes as well. The time courses of increases in phyllopodial and gut ESAs in brine shrimps transferred from 100% SW to 400 % SW are consistent with the induction of new Na+/K+-ATPase; 4–7 days was required for significant increases to occur. Haemolymph ion analyses and transepithelial potential differences, measured in brine shrimp acclimated in all the SW media, indicate that chloride is actively transported out of the brine shrimp while sodium is very close to electrochemical equilibrium across the body wall. Thus, the metepipodites of the brine shrimp appear to possess cells with many functional similarities to the teleost branchial chloride cells.
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Sequeira, A. M. M., J. P. Rodríguez, V. M. Eguíluz, R. Harcourt, M. Hindell, D. W. Sims, C. M. Duarte, et al. "Convergence of marine megafauna movement patterns in coastal and open oceans." Proceedings of the National Academy of Sciences 115, no. 12 (February 26, 2018): 3072–77. http://dx.doi.org/10.1073/pnas.1716137115.
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The extent of increasing anthropogenic impacts on large marine vertebrates partly depends on the animals’ movement patterns. Effective conservation requires identification of the key drivers of movement including intrinsic properties and extrinsic constraints associated with the dynamic nature of the environments the animals inhabit. However, the relative importance of intrinsic versus extrinsic factors remains elusive. We analyze a global dataset of ∼2.8 million locations from >2,600 tracked individuals across 50 marine vertebrates evolutionarily separated by millions of years and using different locomotion modes (fly, swim, walk/paddle). Strikingly, movement patterns show a remarkable convergence, being strongly conserved across species and independent of body length and mass, despite these traits ranging over 10 orders of magnitude among the species studied. This represents a fundamental difference between marine and terrestrial vertebrates not previously identified, likely linked to the reduced costs of locomotion in water. Movement patterns were primarily explained by the interaction between species-specific traits and the habitat(s) they move through, resulting in complex movement patterns when moving close to coasts compared with more predictable patterns when moving in open oceans. This distinct difference may be associated with greater complexity within coastal microhabitats, highlighting a critical role of preferred habitat in shaping marine vertebrate global movements. Efforts to develop understanding of the characteristics of vertebrate movement should consider the habitat(s) through which they move to identify how movement patterns will alter with forecasted severe ocean changes, such as reduced Arctic sea ice cover, sea level rise, and declining oxygen content.
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Kida, Shinichiro. "The Impact of Open Oceanic Processes on the Antarctic Bottom Water Outflows." Journal of Physical Oceanography 41, no. 10 (October 1, 2011): 1941–57. http://dx.doi.org/10.1175/2011jpo4571.1.
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Abstract The impact of open oceanic processes on the Antarctic Bottom Water (AABW) outflows is investigated using a numerical model with a focus on outflows that occur through deep channels. A major branch of the AABW outflow is known to occur as an overflow from the Filchner Depression to the Weddell Sea through a deep channel a few hundred kilometers wide and a sill roughly 500 m deep. When this overflow enters the Weddell Sea, it encounters the Antarctic Slope Front (ASF) at the shelf break, a density front commonly found along the Antarctic continental shelf break. The presence of an AABW outflow and the ASF create a v-shaped isopycnal structure across the shelf break, indicating an interaction between the overflow and oceanic processes. Model experiments show the overflow transport to increase significantly when an oceanic wind stress increases the depth of the ASF. This enhancement of overflow transport occurs because the channel walls allow a pressure gradient in the along-slope direction to exist and the overflow transport is geostrophically controlled with its ambient oceanic water at the shelf break. Because the ASF is associated with a lighter water mass that reaches the depth close to that of the channel, an increase in its depth increases the density gradient across the shelf break and therefore the geostrophic overflow transport. The enhancement of overflow transport is also likely to result in a lighter overflow water mass, although such an adjustment of density likely occurs on a much longer time scale than the adjustment of transport.
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Woutersen, Amber, Phillip E. Jardine, Raul Giovanni Bogotá-Angel, Hong-Xiang Zhang, Daniele Silvestro, Alexandre Antonelli, Elena Gogna, et al. "A novel approach to study the morphology and chemistry of pollen in a phylogenetic context, applied to the halophytic taxon Nitraria L.(Nitrariaceae)." PeerJ 6 (July 19, 2018): e5055. http://dx.doi.org/10.7717/peerj.5055.
Full textAbstract:
Nitraria is a halophytic taxon (i.e., adapted to saline environments) that belongs to the plant family Nitrariaceae and is distributed from the Mediterranean, across Asia into the south-eastern tip of Australia. This taxon is thought to have originated in Asia during the Paleogene (66–23 Ma), alongside the proto-Paratethys epicontinental sea. The evolutionary history of Nitraria might hold important clues on the links between climatic and biotic evolution but limited taxonomic documentation of this taxon has thus far hindered this line of research. Here we investigate if the pollen morphology and the chemical composition of the pollen wall are informative of the evolutionary history of Nitraria and could explain if origination along the proto-Paratethys and dispersal to the Tibetan Plateau was simultaneous or a secondary process. To answer these questions, we applied a novel approach consisting of a combination of Fourier Transform Infrared spectroscopy (FTIR), to determine the chemical composition of the pollen wall, and pollen morphological analyses using Light Microscopy (LM) and Scanning Electron Microscopy (SEM). We analysed our data using ordinations (principal components analysis and non-metric multidimensional scaling), and directly mapped it on the Nitrariaceae phylogeny to produce a phylomorphospace and a phylochemospace. Our LM, SEM and FTIR analyses show clear morphological and chemical differences between the sister groups Peganum and Nitraria. Differences in the morphological and chemical characteristics of highland species (Nitraria schoberi, N. sphaerocarpa, N. sibirica and N. tangutorum) and lowland species (Nitraria billardierei and N. retusa) are very subtle, with phylogenetic history appearing to be a more important control on Nitraria pollen than local environmental conditions. Our approach shows a compelling consistency between the chemical and morphological characteristics of the eight studied Nitrariaceae species, and these traits are in agreement with the phylogenetic tree. Taken together, this demonstrates how novel methods for studying fossil pollen can facilitate the evolutionary investigation of living and extinct taxa, and the environments they represent.
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Al-Halbouni, Djamil, Eoghan P. Holohan, Abbas Taheri, Robert A. Watson, Ulrich Polom, Martin P. J. Schöpfer, Sacha Emam, and Torsten Dahm. "Distinct element geomechanical modelling of the formation of sinkhole clusters within large-scale karstic depressions." Solid Earth 10, no. 4 (July 29, 2019): 1219–41. http://dx.doi.org/10.5194/se-10-1219-2019.
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Abstract. The 2-D distinct element method (DEM) code (PFC2D_V5) is used here to simulate the evolution of subsidence-related karst landforms, such as single and clustered sinkholes, and associated larger-scale depressions. Subsurface material in the DEM model is removed progressively to produce an array of cavities; this simulates a network of subsurface groundwater conduits growing by chemical/mechanical erosion. The growth of the cavity array is coupled mechanically to the gravitationally loaded surroundings, such that cavities can grow also in part by material failure at their margins, which in the limit can produce individual collapse sinkholes. Two end-member growth scenarios of the cavity array and their impact on surface subsidence were examined in the models: (1) cavity growth at the same depth level and growth rate; (2) cavity growth at progressively deepening levels with varying growth rates. These growth scenarios are characterised by differing stress patterns across the cavity array and its overburden, which are in turn an important factor for the formation of sinkholes and uvala-like depressions. For growth scenario (1), a stable compression arch is established around the entire cavity array, hindering sinkhole collapse into individual cavities and favouring block-wise, relatively even subsidence across the whole cavity array. In contrast, for growth scenario (2), the stress system is more heterogeneous, such that local stress concentrations exist around individual cavities, leading to stress interactions and local wall/overburden fractures. Consequently, sinkhole collapses occur in individual cavities, which results in uneven, differential subsidence within a larger-scale depression. Depending on material properties of the cavity-hosting material and the overburden, the larger-scale depression forms either by sinkhole coalescence or by widespread subsidence linked geometrically to the entire cavity array. The results from models with growth scenario (2) are in close agreement with surface morphological and subsurface geophysical observations from an evaporite karst area on the eastern shore of the Dead Sea.
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GIAKOUMI, S., and G. D. KOKKORIS. "Effects of habitat and substrate complexity on shallow sublittoral fish assemblages in the Cyclades Archipelago, North-eastern Mediterranean Sea." Mediterranean Marine Science 14, no. 1 (February 21, 2013): 58. http://dx.doi.org/10.12681/mms.318.
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This is the first study to explore fish community structure and its relations to habitat and topographic complexity in the shallow coastal waters of the Cyclades Archipelago, North-eastern Mediterranean Sea. In situ visual surveys were carried out at 233 sampling sites in 26 islands of the Cyclades Archipelago. Fish community parameters and biomass were estimated across seven substrate types: sand, seagrass, vertical walls, boulders, horizontal/subhorizontal continuous rock, rocky substrate with patches of sand, and rocky substrate with patches of sand and Posidonia oceanica. Topographic complexity and percentage of algal cover were estimated on hard substrate. Substrate type was found to be a determining factor affecting the structure and composition of fish assemblages. Species number, abundance and biomass were significantly lower in sandy areas and always higher on hard substrates, with seagrass habitats presenting intermediate values. Topographic complexity in rocky bottoms did not seem to affect species richness, density or biomass. This study provides a baseline for future evaluation of changes produced by potential management actions such as the creation of marine protected areas in the study region.
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McNeil, David H., and Lisa A. Neville. "On a grain of sand – a microhabitat for the opportunistic agglutinated foraminifera <i>Hemisphaerammina apta</i> n. sp., from the early Eocene Arctic Ocean." Journal of Micropalaeontology 37, no. 1 (February 8, 2018): 295–303. http://dx.doi.org/10.5194/jm-37-295-2018.
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Abstract. Hemisphaerammina apta n. sp. is an attached monothalamous agglutinated foraminifera discovered in shelf sediments of the early Eocene Arctic Ocean. It is a simple yet distinctive component of the endemic agglutinated foraminiferal assemblage that colonized the Arctic Ocean after the microfaunal turnover caused by the Paleocene–Eocene Thermal Maximum. Associated foraminifera are characterized by a high percentage of monothalamous species (up to 60 %) and are entirely agglutinated indicating a brackish (mesohaline) early Eocene Arctic Ocean. Hemisphaerammina apta occurs exclusively as individuals attached to fine detrital grains (0.2 to 1.8 mm) of sediment. It is a small species (0.06 to 0.2 mm in diameter), fine-grained, with a low hemispherical profile, no floor across the attachment area, no substantive marginal flange, no internal structures, and no aperture. Lacking an aperture, it apparently propagated and fed through minute (micrometre-sized) interstitial pores in the test wall. Attachment surfaces vary from concave to convex and rough to smooth. Grains for attachment are diverse in shape and type but are predominantly of quartz and chert. The presence of H. apta in the early Eocene was an opportunistic response to an environment with an active hydrological system (storm events). Attachment to grains of sand would provide a more stable base on a sea floor winnowed by storm-generated currents. Active transport is indicated by the relative abundance of reworked foraminifera mixed with in situ species. Contemporaneous reworking and colonization by H. apta is suggested by its attachment to a reworked specimen of Cretaceous foraminifera.
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Thomas, Leif N., and Callum J. Shakespeare. "A New Mechanism for Mode Water Formation involving Cabbeling and Frontogenetic Strain at Thermohaline Fronts." Journal of Physical Oceanography 45, no. 9 (September 2015): 2444–56. http://dx.doi.org/10.1175/jpo-d-15-0007.1.
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AbstractA simple analytical model is used to elucidate a potential mechanism for steady-state mode water formation at a thermohaline front that involves frontogenesis, submesoscale lateral mixing, and cabbeling. This mechanism is motivated in part by recent observations of an extremely sharp, density-compensated front at the North Wall of the Gulf Stream. Here, the intergyre, along-isopycnal, salinity–temperature difference is compressed into a span of a few kilometers, making the flow susceptible to cabbeling. The sharpness of the front is caused by frontogenetic strain, which is presumably balanced by submesoscale lateral mixing processes. The balance is studied with the simple model, and a scaling is derived for the amount of water mass transformation resulting from the ensuing cabbeling. The transformation scales with the strain rate, equilibrated width of the front, and the square of the isopycnal temperature contrast across the front. At the major ocean fronts where mode waters are found, this isopycnal temperature contrast decreases with increasing density near the isopycnal layers where mode waters reside. This implies that cabbeling should result in a convergent diapycnal mass flux into mode water density classes. The scaling for the transformation suggests that at these fronts the process could generate 0.01–1 Sverdrups (Sv; 1 Sv ≡ 106 m3 s−1) of mode water. These formation rates, while smaller than mode water formation by air–sea fluxes, should be independent of season and thus could fill select isopycnal layers continuously and play an important role in the dynamics of mode waters on interannual time scales.
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Reali-Forster, Chiara, Theodor Kolobow, Matteo Giacomini, Tomayoshi Hayashi, Koji Horiba, and Victor J. Ferrans. "New Ultrathin-walled Endotracheal Tube with a Novel Laryngeal Seal Design." Anesthesiology 84, no. 1 (January 1, 1996): 162–72. http://dx.doi.org/10.1097/00000542-199601000-00019.
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Background A new endotracheal tube (ETT) was fabricated and tested in sheep. It had no tracheal cuff; airway seal was achieved at the level of the glottis through a no-pressure seal made of "gills"; the laryngeal portion was oval-shaped; and the wall thickness was reduced to 0.2 mm. Methods Sheep were tracheally intubated either with a standard tube or with the new tube, and their lungs were mechanically ventilated for 1 or 3 days. Air leak was recorded at different peak inspiratory pressures (PIPs). Liquid seepage into the trachea was assessed using an indicator dye. Tracheolaryngeal lesions were scored grossly and histologically. Results There was no air leak up to 40 cmH2O of PIP, in either group, in short- and long-term studies. Methylene blue leaked across the cuff in two sheep with standard ETTs. No dye leaked across the gills with the new ETTs. In the new ETT group, the trachea appeared better preserved, grossly and histologically, than in the standard ETT group at both 1 and 3 days (P < 0.05). At day 1, the larynx and vocal cords appeared grossly less injured in the new ETT group (P < 0.05), whereas there was no difference at day 3. Histology did not show significant difference on vocal cords, epiglottis, and larynx between the two groups at any time. Conclusions The novel, no-pressure seal design of the new ETT is highly effective in preventing air leak and aspiration. It causes no significant tracheal injury.
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Beaujean, Pierre-Philippe J., and Matthew D. Staska. "High-Frequency Underwater Acoustic Propagation in a Port Modeled as a Three-Dimensional Duct Closed at One End Using the Method of Images." Advances in Acoustics and Vibration 2012 (June 3, 2012): 1–15. http://dx.doi.org/10.1155/2012/929174.
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A computer-efficient model for underwater acoustic propagation in a shallow, three-dimensional rectangular duct closed at one end has been developed using the method of images. The duct simulates a turning basin located in a port, surrounded with concrete walls, and filled with sea water. The channel bottom is composed of silt. The modeled impulse response is compared with the impulse response measured between 15 kHz and 33 kHz. Despite small sensor-position inaccuracies and an approximated duct geometry, the impulse response can be modeled with a relative echo magnitude error of 1.62 dB at worst and a relative echo location error varying between 0% and 4% when averaged across multiple measurements and sensor locations. This is a sufficient level of accuracy for the simulation of an acoustic communication system operating in the same frequency band and in shallow waters, as time fluctuations in echo magnitude commonly reach 10 dB in this type of environment.
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Pernthaler, Jakob, Annelie Pernthaler, and Rudolf Amann. "Automated Enumeration of Groups of Marine Picoplankton after Fluorescence In Situ Hybridization." Applied and Environmental Microbiology 69, no. 5 (May 2003): 2631–37. http://dx.doi.org/10.1128/aem.69.5.2631-2637.2003.
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ABSTRACT We describe here an automated system for the counting of multiple samples of double-stained microbial cells on sections of membrane filters. The application integrates an epifluorescence microscope equipped with motorized z-axis drive, shutters, and filter wheels with a scanning stage, a digital camera, and image analysis software. The relative abundances of specific microbial taxa are quantified in samples of marine picoplankton, as detected by fluorescence in situ hybridization (FISH) and catalyzed reporter deposition. Pairs of microscopic images are automatically acquired from numerous positions at two wavelengths, and microbial cells with both general DNA and FISH staining are counted after object edge detection and signal-to-background ratio thresholding. Microscopic fields that are inappropriate for cell counting are automatically excluded prior to measurements. Two nested walk paths guide the device across a series of triangular preparations until a user-defined number of total cells has been analyzed per sample. A backup autofocusing routine at incident light allows automated refocusing between individual samples and can reestablish the focal plane after fatal focusing errors at epifluorescence illumination. The system was calibrated to produce relative abundances of FISH-stained cells in North Sea samples that were comparable to results obtained by manual evaluation. Up to 28 preparations could be analyzed within 4 h without operator interference. The device was subsequently applied for the counting of different microbial populations in incubation series of North Sea waters. Automated digital microscopy greatly facilitates the processing of numerous FISH-stained samples and might thus open new perspectives for bacterioplankton population ecology.
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MENDELSOHN, ROBERT. "THE ECONOMICS OF ADAPTATION TO CLIMATE CHANGE IN DEVELOPING COUNTRIES." Climate Change Economics 03, no. 02 (May 2012): 1250006. http://dx.doi.org/10.1142/s2010007812500066.
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Adaptations are changes in behavior and capital motivated by climate change. Economic theory suggests that adaptations are efficient (desirable) only if their benefit exceeds their cost. Private adaptations are likely to be efficient because the benefits and cost accrue to the decision maker. With some important exceptions, private adaptation is likely to be done efficiently by markets. Public adaptations, however, benefit many people. Markets are not likely to make efficient public adaptations because they cannot coordinate payments from multiple consumers. Governments need to be responsible for public adaptations. However, government must think carefully about being efficient. Empirically, little is known about what precise changes in behavior are efficient, where such changes should take place and when they should take place. The empirical literature has largely focused on how actors have adapted to the current range of climates across the earth. From these studies, researchers are extrapolating what changes would make sense in the future as climate changes. The results suggest that adaptations are local in nature and therefore look like patchwork adjustments across space. They depend on the current local climate, how it changes and the various local conditions. Although public adaptations in health and conservation look promising, there are virtually no economic analyses of their potential. Overall, adaptation can be very effective at reducing damages, for example, by building sea walls to protect from inundation, and seizing new opportunities, for example, by growing in crops in places that were previously too cold. Research must now focus on making the practical steps that turn that potential into reality.
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Keep, M., L. Beck, and P. Bekkers. "COMPLEX MODIFIED THRUST SYSTEMS ALONG THE SOUTHERN MARGIN OF EAST TIMOR." APPEA Journal 45, no. 1 (2005): 297. http://dx.doi.org/10.1071/aj04025.
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Seismic structural interpretation of data across three basins along the southern coast of East Timor (the Suai, Beaco and Aliambata basins) reveals a complex deformation history dominated by intense thrust deformation within the thick (>3 km) Plio-Pleistocene sequence.Our interpreted deformation sequence of the clay-dominated rocks includes a series of south-directed, low-angle thrusts creating extensive thrust piles, and in places, antiformal stacks. These thickened piles exhibit later modification by crestal collapse. Rapid thickening destabilised the growing thrust packages, and caused regional-scale slumping of material into the Timor Trough to the south. The slumping disrupted thrust fronts and caused significant offset at the sea floor. Finally, shale injection and diapirism along the slump faults re-elevated some of the hanging-walls of the slumps.Oil and gas seeps, which occur mainly in southern East Timor, follow structural trends parallel to those offshore. Although sourced from proposed Triassic source rocks, uplift, exposure and subsequent leakage from these seeps probably occurred within the last 2 Ma, and possibly even later, co-eval with Plio-Pleistocene deformation. The proximity of oil seeps to fold and thrust deformation raises the possibility that additional Triassic or other Mesozoic section may occur at various structural levels within the deformed sedimentary wedge.
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Koen, E. L., J. Bowman, and P. J. Wilson. "Isolation of peripheral populations of Canada lynx (Lynx canadensis)." Canadian Journal of Zoology 93, no. 7 (July 2015): 521–30. http://dx.doi.org/10.1139/cjz-2014-0227.
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Landscape barriers to gene flow, such as rivers, can affect animal populations by limiting the potential for rescue of these isolated populations. We tested the riverine barrier hypothesis, predicting that the St. Lawrence River in eastern Canada would cause genetic divergence of Canada lynx (Lynx canadensis Kerr, 1792) populations by restricting dispersal and gene flow. We sampled 558 lynx from eastern Canada and genotyped these at 14 microsatellite loci. We found three genetic clusters, defined by the St. Lawrence River and the Strait of Belle Isle, a waterway separating Newfoundland from mainland Canada. However, these waterways were not absolute barriers, as we found 24 individuals that appeared to have crossed them. Peripheral populations of lynx are threatened in parts of Canada and the USA, and it is thought that these populations are maintained by immigration from the core. Our findings suggest that in eastern North America, rescue might be less likely because the St. Lawrence River restricts dispersal. We found that ice cover was often sufficient to allow lynx to walk across the ice in winter. If lynx used ice bridges in winter, then climate warming could cause a reduction in the extent and longevity of river and sea ice, further isolating these peripheral lynx populations.
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Leong, Russell. "Friendship Across the Sea." Amerasia Journal 28, no. 3 (January 2002): iv—xl. http://dx.doi.org/10.17953/amer.28.3.q57662p715g147g3.
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Schwartz, Donald, and South Carolina Educational Television. "Family across the Sea." History Teacher 25, no. 4 (August 1992): 523. http://dx.doi.org/10.2307/494358.
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Lack, David. "MIGRATION ACROSS THE SEA." Ibis 101, no. 3-4 (April 3, 2008): 374–99. http://dx.doi.org/10.1111/j.1474-919x.1959.tb02395.x.
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Nwachukwu-Agbada, J. O. J., and Idzia Ahmad. "A Shout across the Wall." World Literature Today 63, no. 4 (1989): 728. http://dx.doi.org/10.2307/40145729.
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Pioline, Boris. "Four ways across the wall." Journal of Physics: Conference Series 346 (February 9, 2012): 012017. http://dx.doi.org/10.1088/1742-6596/346/1/012017.
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Alt, Susan M., and Timothy R. Pauketat. "WHY WALL TRENCHES?" Southeastern Archaeology 30, no. 1 (June 2011): 108–22. http://dx.doi.org/10.1179/sea.2011.30.1.008.
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Davis, Jr., Albert B. "HISTORY OF THE GALVESTON SEA WALL." Coastal Engineering Proceedings 1, no. 2 (January 1, 2000): 24. http://dx.doi.org/10.9753/icce.v2.24.
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Galveston Island, one of the long, narrow barrier beaches that fringe the Gulf Coast of Texas, is a low, sandy formation about 28 miles long and from -g to 3 miles wide. In its natural state the Gulf shore was bordered by an area of sand dunes rising to heights of 12 to 15 feet above the natural surface of the island. The availability of deep water along the bay side of the island led to the early development of the city of Galveston on the east end of the island. In its early days the city was protected from hurricane tides by the sand dunes along the Gulf front. The rapid development of the city in the latter part of the 19th century, especially its increasing importance as a summer resort, lead to the removal of the sand dunes along the beach front for fill and to permit easy access to the beach. Without the dunes the city was unprotected from the fury of the hurricanes. The danger to the city was realized by a number of persons, and several plans for storm protection had been developed; however, because of financing difficulties and general public apathy none of these plans was carried out. Figure one shows a map of Galveston Island with development as it was in 1900.
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Macintyre, Stuart. "Laslett, Colliers Across the Sea." Scottish Historical Review 80, no. 2 (October 2001): 291–93. http://dx.doi.org/10.3366/shr.2001.80.2.291.
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Farmer, David M., Laurence Armi, and Andrew T. Young. "Mirages across the Salish Sea." Weather 69, no. 8 (July 28, 2014): 215–20. http://dx.doi.org/10.1002/wea.2283.
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