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Tidal Resuspension And Deposition Of Particulate Matter In The Oyster Grounds, North Sea, Wim Van Raaphorst, Hans Malschaert, Hans Van Haren Jan 1998

Tidal Resuspension And Deposition Of Particulate Matter In The Oyster Grounds, North Sea, Wim Van Raaphorst, Hans Malschaert, Hans Van Haren

Journal of Marine Research

Moored current meters, fluorom eters and transmissometers were used in combination with sediment traps (aspect ratio >4) and shipborne sampling to determine fluxes of deposition and resuspension of total suspended matter (TSM) under tidal action in the 45 m deep Oyster Grounds, North Sea. Here, we present data from the mixed layer below the major thermocline at about 20 m above the bottom (mab) as obtained during a 14-day period of calm weather in July 1994. Around neap tide near-bottom current velocities remained smaller than 0.15 m s-1 and TSM was dominated by particles advected from a relatively turbid …

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Under-Ice Observations Of Water Column Temperature, Salinity And Spring Phytoplankton Dynamics: Eastern Bering Sea Shelf, P. J. Stabeno, J. D. Schumacher, R. F. Davis, J. M. Napp Jan 1998

Under-Ice Observations Of Water Column Temperature, Salinity And Spring Phytoplankton Dynamics: Eastern Bering Sea Shelf, P. J. Stabeno, J. D. Schumacher, R. F. Davis, J. M. Napp

Journal of Marine Research

The inundation of two moored platforms by sea ice in late winter and early spring of 1995 provided unique time series of water column temperature, salinity, estimated chlorophyll-a, and phytoplankton fluorescence under advancing and retreating sea ice. One platform was located at 72 m in the weakly advective middle shelf regime. Here, chlorophyll-a concentrations began increasing shortly after the arrival of the ice (arch) during the period of weak stratification and continued to increase while wind actively mixed the water column to >60 m. Changes in water column structure and properties resulted from an event of strong …

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Deep Water Properties, Velocities, And Dynamics Over Ocean Trenches, Gregory C. Johnson Jan 1998

Deep Water Properties, Velocities, And Dynamics Over Ocean Trenches, Gregory C. Johnson

Journal of Marine Research

Observations of water properties and deep currents over several trenches in the Pacific Ocean central basins give consistent evidence for recent ventilation of water below the trench sills and cyclonic sense of circulation over the trenches. A dynamical argument for this pattern is advanced. First, a review of previous analyses of hydrographic data shows that the trenches are well ventilated by dense bottom water, that within the trenches this bottom water generally spreads away from its source, and that a cyclonic sense of circulation is suggested over some trenches. Then, this cyclonic sense of circulation over the trenches is further …

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A Numerical Study Of Layer Formation Due To Fingers In Double-Diffusive Convection In A Vertically-Bounded Domain, Tamay M. Özgökmen, Oleg E. Esenkov, Donald B. Olson Jan 1998

A Numerical Study Of Layer Formation Due To Fingers In Double-Diffusive Convection In A Vertically-Bounded Domain, Tamay M. Özgökmen, Oleg E. Esenkov, Donald B. Olson

Journal of Marine Research

The evolution of fingers in a double-diffusive system is investigated using numerical integration of two-dimensional equations of motion for an incompressible, Boussinesq fluid. The computational domain is periodic in the horizontal direction and is closed with no-flux boundary conditions in the vertical direction. The main result of this study is the evolution of the system from initially linear profiles for both fast and slow diffusing components to a layered state characterized by a finger zone sandwiched between two mixed layers. The horizontal boundaries in this system play an important role in the development of the layered state. At the top …

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The Rectification Of Wind-Driven Flow Due To Its Instabilities, Caroline A. Katsman, Henk A. Dijkstra, Sybren S. Drijfhout Jan 1998

The Rectification Of Wind-Driven Flow Due To Its Instabilities, Caroline A. Katsman, Henk A. Dijkstra, Sybren S. Drijfhout

Journal of Marine Research

Within a quasi-geostrophic two-layer model of the wind-driven ocean circulation, an idealized symmetric double gyre flow is considered. When lateral friction is large enough, this flow is steady and characterized by a motionless lower layer. As friction is decreased, the flow undergoes a transition to time-dependence through a Hopf bifurcation, associated with a mixed barotropic/baroclinic instability. It is shown that the nonlinear self-interaction of this oscillatory unstable mode induces a nonzero time mean response in the lower layer. The origin of this deep flow is clarified through a weakly nonlinear analysis near critical conditions. It is explained how the perturbation …

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Process-Specific Cues For Recruitment In Sedimentary Environments: Geochemical Signals?, Sarah A. Woodin, Roberta L. Marinelli, Sara M. Lindsay Jan 1998

Process-Specific Cues For Recruitment In Sedimentary Environments: Geochemical Signals?, Sarah A. Woodin, Roberta L. Marinelli, Sara M. Lindsay

Journal of Marine Research

The most biologically and geochemically active marine sediments are characterized by steep chemical gradients within the top centimeters of sediment (Berner, 1980). A common feature of these environments is disruptions of surface sediments by both physical and biotic forces. Growth and mortality rates for new recruits are affected by many of these surface perturbations. At the same time, these disturbances also impose a discontinuity in concentration across the sediment-water interface, and accordingly, a change in surface chemistry. In this paper we present evidence that the cue used by juveniles to distinguish between recently disturbed and undisturbed surfaces may be disruption …

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Seabed Drag Coefficient Over Natural Beds Of Horse Mussels (Atrina Zelandica), Malcolm O. Green, Judi E. Hewitt, Simon F. Thrush Jan 1998

Seabed Drag Coefficient Over Natural Beds Of Horse Mussels (Atrina Zelandica), Malcolm O. Green, Judi E. Hewitt, Simon F. Thrush

Journal of Marine Research

Measurements of seabed drag coefficient, C100, were made under tidal currents at four sites in Mahurangi Harbour, New Zealand. At the first three sites the dominant roughness element was the pinnid bivalve, Atrina zelandica (horse mussel). At the fourth site, which was devoid of horse mussels but covered in cockle shells, patches of seaweed and crab burrows, C100 was smallest (0.0055), but still twice as large as the value typically applied to abiotic, flat, cohesionless seabeds (0.0025). The mean drag coefficient plus-or-minus standard error at the three sites with horse mussels was: 0.0082 ± 0.0010 (site 1); …

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Three-Dimensional Stirring Of Thermohaline Fronts, Patrice Klein, Anne-Marie Treguier, Bach Lien Hua Jan 1998

Three-Dimensional Stirring Of Thermohaline Fronts, Patrice Klein, Anne-Marie Treguier, Bach Lien Hua

Journal of Marine Research

This study investigates the stirring of the thermohaline anomalies in a fully turbulent quasigeostrophic stratified flow. Temperature and salinity fields are permanently forced at large scales and are related to density by a linear equation of state. We show, using some inherent properties of quasi-geostrophic turbulence, that the 3-D ageostrophic circulation is the key dynamical characteristic that governs the strength and the spatial distribution of small-scale thermohaline fronts that are strongly density compensated. The numerical simulations well illustrate the formation by the mesoscale eddy field of sharp thermohaline fronts that are mainly located in the saddle regions and around the …

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Temporal Variability And Composition Of Settling Particle Fluxes On The Barcelona Continental Margin (Northwestern Mediterranean), P. Puig, A. Palanques Jan 1998

Temporal Variability And Composition Of Settling Particle Fluxes On The Barcelona Continental Margin (Northwestern Mediterranean), P. Puig, A. Palanques

Journal of Marine Research

The results of a year-long sediment-trap experiment provide the first direct observations of sediment fluxes to the seafloor on the Barcelona continental margin. Time-series of vertical particle fluxes and major constituents (organic carbon, biogenic silica, calcium carbonate and aluminosilicates) were determined inside and in the vicinity of the Foix submarine canyon from May 1993 to April 1994. The spatial and temporal variability of bi-weekly total mass fluxes indicate significant high frequency variability related to physical and biological processes at this site. The Foix submarine canyon acts as an actual conduit for transport of sediment from the shelf to the slope, …

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Excretion Of Trace Elements By Marine Copepods And Their Bioavailability To Diatoms, Wen-Xiong Wang, Nicholas S. Fisher Jan 1998

Excretion Of Trace Elements By Marine Copepods And Their Bioavailability To Diatoms, Wen-Xiong Wang, Nicholas S. Fisher

Journal of Marine Research

We measured the physiological turnover rate (= excretion rate) of five trace elements (Ag, Cd, Co, Se and Zn) in the marine copepod Temora longicornis following feeding on radiolabeled diatoms. The turnover rate constants of trace elements in copepods were high (0.05 to 0.38 d-1) and were comparable to published values for N and P excretion. Ag, Cd and Co were excreted at higher rates than Se and Zn. Turnover rate constants of Ag, Cd, and Co also increased with increasing food concentration, whereas excretion of Se and Zn was not affected by food concentration. There was little …

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The Non-Wavelike Response Of A Continental Shelf To Wind, G. T. Csanady Jan 1998

The Non-Wavelike Response Of A Continental Shelf To Wind, G. T. Csanady

Journal of Marine Research

An overlooked aspect of continental shelf wave generation by wind is that a non-wavelike flow field may accompany the waves. To explore this possibility, we calculate the response of an inclined plane shelf to suddenly applied alongshore wind, affecting a finite portion of the coast. The calculations are based on the classical theory of continental shelf waves, supposing low frequency motions and invoking the boundary layer approximation (alongshore scales much longer than cross-shore ones). The results reveal non-wavelike circulations, with or without bottom friction, on a shelf of finite or unlimited width, unaffected by changing offshore boundary conditions. In the …

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Nonlinear Limits To Ocean Thermal Structure, N. P. Fofonoff Jan 1998

Nonlinear Limits To Ocean Thermal Structure, N. P. Fofonoff

Journal of Marine Research

The nonlinear volume changes associated with diffusion and mixing of different seawater types produce significant conversions of gravitational potential energy to kinetic energy to maintain and enhance mixing processes and to limit the magnitudes of temperature gradients that can persist in the ocean. Several examples are given to illustrate these critical temperature gradients beyond which conversion exceeds local energy consumption by mixing. The vertical temperature gradients in the Gulf Stream reduce downstream from Cape Hatteras to the critical limit found in the North Atlantic thermocline. The limiting gradients are also seen in surface thermoclines and in "staircase" structures. Although the …

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Linear Ocean Circulation Theory With Realistic Bathymetry, Rick Salmon Jan 1998

Linear Ocean Circulation Theory With Realistic Bathymetry, Rick Salmon

Journal of Marine Research

The linear equations governing stratified, wind-driven flow in an ocean of arbitrary shape may be combined into a single "advection-diffusion" equation for the pressure , in which the "flow" advecting  includes a delta-function contribution at the ocean bottom in the sense of southward "advection" of  along western continental slopes. This interpretation of the -equation helps to explain numerical solutions obtained with a finite-element model incorporating realistic North Atlantic bathymetry.

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On The Stability Of The Wind-Driven Circulation, P. Berloff, S. P. Meacham Jan 1998

On The Stability Of The Wind-Driven Circulation, P. Berloff, S. P. Meacham

Journal of Marine Research

This work examines the instabilities of steady circulations driven by stationary single-gyre wind forcing in closed rectangular basins with different aspect ratios. The stratified ocean is modeled with quasi-geostrophic 1.5-layer (equivalent-barotropic) and two-layer models. As friction is reduced, a stability threshold is encountered. In the vicinity of this threshold, unstable steady states and their unstable eigenmodes are determined. The structures of the eigenmodes and their associated energy conversion terms allow us to characterize the instabilities. In each case, the loss of stability is associated with an oscillatory instability. Several different instability mechanisms are observed. Which of these is responsible for …

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Observations Of Temporal Changes Of Tritium-3he Age In The Eastern North Atlantic Thermocline: Evidence For Changes In Ventilation, Paul E. Robbins, William J. Jenkins Jan 1998

Observations Of Temporal Changes Of Tritium-3he Age In The Eastern North Atlantic Thermocline: Evidence For Changes In Ventilation, Paul E. Robbins, William J. Jenkins

Journal of Marine Research

A compilation of fifteen years of tritium and 3He measurements is used to examine the ventilation of the eastern North Atlantic subtropical gyre with specific emphasis on the temporal character of the tracer age field. A multivariate regression analysis in the form of a spatiotemporal Taylor expansion is applied to observations interpolated onto isopycnal surfaces. The time-dependent component of the tracer age field is found to be statistically significant, explaining approximately 10% of the variance of the tracer age observations in the upper thermocline (σ = 26.5) and increasing to roughly 50% of the variance in the lower thermocline …

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Tidal Mixing And Cross-Frontal Particle Exchange Over A Finite Amplitude Asymmetric Bank: A Model Study With Application To Georges Bank, Changsheng Chen, Robert C. Beardsley Jan 1998

Tidal Mixing And Cross-Frontal Particle Exchange Over A Finite Amplitude Asymmetric Bank: A Model Study With Application To Georges Bank, Changsheng Chen, Robert C. Beardsley

Journal of Marine Research

Tidal mixing, internal wave bores, and cross-bank particle transport over a finite amplitude asymmetric bank are examined using a two-dimensional primitive equation ocean model with Mellor and Yamada (level 2.5) turbulent closure. Driven by the surface M2 tide, the model results show that tidal mixing exhibits temporal and spatial asymmetries on southern and northern flanks of the bank. It is strongest near the bottom around maximum on-bank tidal flow as a result of gravitational instability when denser water is advected upslope over lighter water. A sharp thermal depression occurs on the steep northern flank, which produces large current shear …

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Small Viscosity Behavior Of A Homogeneous, Quasi-Geostrophic, Ocean Circulation Mode, Robert B. Scott, David N. Straub Jan 1998

Small Viscosity Behavior Of A Homogeneous, Quasi-Geostrophic, Ocean Circulation Mode, Robert B. Scott, David N. Straub

Journal of Marine Research

Insensitivity to turbulent closure in the wind-driven nonlinear Stommel-Munk model is addressed theoretically and numerically. The QG energy equation is used to show that, with the assumption that the maximum velocities occur at inertial length scales or smaller, a Sverdrup interior is consistent with the small Rossby number assumption only when the frictional parameters exceed critical values. For frictional parameters smaller than these values, valid solutions must decrease the energy source. This is possible for non-Sverdrup solutions since the energy source is dependent on the solution. The steady-state behavior of the model was investigated via a pseudo-arclength continuation algorithm. Dependence …

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Larval Settlement In Turbulent Pipe Flows, James E. Eckman, David O. Duggins Jan 1998

Larval Settlement In Turbulent Pipe Flows, James E. Eckman, David O. Duggins

Journal of Marine Research

In two experiments, larval settlement was studied within a series of pipes, each containing steady, turbulent, flowing seawater. The study was designed to determine effects of flow (speed, turbulence intensity and wall shear stress) and surface orientation on rates of settlement of larvae of various taxa, and to relate variability in patterns of settlement among orientations and flows to the concomitant variability expected in rates of larval supply or delivery to the pipe walls. Patterns of settlement of all five taxa (the barnacle Balanus spp., the mussel Mytilus trossulus, the serpulid polychaete Pseudochitinopoma occidentalis, the cyclostome bryozoan Tubulipora sp., …

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Cloning, Sequencing And Partial Characterization Of The 5' Flanking Region Of The Mouse Neutrophil Collagenase Gene : Conservation With The Human Neutrophil Collagenase Regulatory Region, Marcoli Cyrille Jan 1998

Cloning, Sequencing And Partial Characterization Of The 5' Flanking Region Of The Mouse Neutrophil Collagenase Gene : Conservation With The Human Neutrophil Collagenase Regulatory Region, Marcoli Cyrille

Yale Medicine Thesis Digital Library

No abstract provided.

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Power And Mysticism In The Introduction Of Anesthesia In Nineteenth Century America, Naomi Strachan Donnelley Jan 1998

Power And Mysticism In The Introduction Of Anesthesia In Nineteenth Century America, Naomi Strachan Donnelley

Yale Medicine Thesis Digital Library

No abstract provided.

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United States Department Of Housing And Urban Development Consolidated Report, United States: Department Of Housing And Urban Development (Hud) Jan 1998

United States Department Of Housing And Urban Development Consolidated Report, United States: Department Of Housing And Urban Development (Hud)

Documents

No abstract provided.

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The Longterm Neuropsychological Effects Of Single-Suture Craniosynostosis On Child Development, Sheela Natesh Magge Jan 1998

The Longterm Neuropsychological Effects Of Single-Suture Craniosynostosis On Child Development, Sheela Natesh Magge

Yale Medicine Thesis Digital Library

No abstract provided.

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Urinary Catecholamines And Cortisol In Attention Deficity/Hyperactivity Disorder, Marcia Dover Jan 1998

Urinary Catecholamines And Cortisol In Attention Deficity/Hyperactivity Disorder, Marcia Dover

Yale Medicine Thesis Digital Library

No abstract provided.

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Smoking Behavior And Health Beliefs In Adolescents With Asthma, Amy Elizabeth Taylor Jan 1998

Smoking Behavior And Health Beliefs In Adolescents With Asthma, Amy Elizabeth Taylor

Yale Medicine Thesis Digital Library

No abstract provided.

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A Critical Analysis Of The Spectral Filtered, Signal-Averaged Electrocardiogram, Naomi Freya Botkin Jan 1998

A Critical Analysis Of The Spectral Filtered, Signal-Averaged Electrocardiogram, Naomi Freya Botkin

Yale Medicine Thesis Digital Library

No abstract provided.

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An Analysis Of Issues Surrounding Disclosure Of The Diagnosis Of Human Immunodeficiency Virus Infection To Children, Reshma Ravi Chugani Jan 1998

An Analysis Of Issues Surrounding Disclosure Of The Diagnosis Of Human Immunodeficiency Virus Infection To Children, Reshma Ravi Chugani

Yale Medicine Thesis Digital Library

No abstract provided.

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Bedside Doppler Identification Of Lower-Extremity Deep-Vein Thrombosis, Gregory Stephen Raskin Jan 1998

Bedside Doppler Identification Of Lower-Extremity Deep-Vein Thrombosis, Gregory Stephen Raskin

Yale Medicine Thesis Digital Library

No abstract provided.

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Postnatal Development Of Olfactory Receptor Cell Axonal Arbors, Jason R. Klenoff Jan 1998

Postnatal Development Of Olfactory Receptor Cell Axonal Arbors, Jason R. Klenoff

Yale Medicine Thesis Digital Library

No abstract provided.

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Neurochemical And Behavioral Tolerance To Cocaine Following Treatment With Cocaine Analogs, Tobias Tong-Po Lee Jan 1998

Neurochemical And Behavioral Tolerance To Cocaine Following Treatment With Cocaine Analogs, Tobias Tong-Po Lee

Yale Medicine Thesis Digital Library

No abstract provided.

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Modulation Of Atp-Sensitive Potassium Channel Activity By Atp-Binding Cassette Transporters : A Model For Channel Regulation, Tong-Yi Yao Jan 1998

Modulation Of Atp-Sensitive Potassium Channel Activity By Atp-Binding Cassette Transporters : A Model For Channel Regulation, Tong-Yi Yao

Yale Medicine Thesis Digital Library

No abstract provided.

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