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Dense Overflow Into A Large Silled Embayment: Tidal Modulation, Fronts And Basin Modes, M. White, Alex E. Hay Jan 1994

Dense Overflow Into A Large Silled Embayment: Tidal Modulation, Fronts And Basin Modes, M. White, Alex E. Hay

Journal of Marine Research

A dense bottom overflow into a 100-km scale silled embayment has been observed for a 70-day period using a coherent array of current meters and thermistor chains. As the internal Rossby radius is less than the width of the bay, the overflow is controlled by rotational dynamics. The flow is strongly modulated by the tide at diurnal, semi-diurnal and fortnightly periods. This causes a series of cold temperature fronts, associated with separate overflow events, to pass through the mooring array. The overflow is also modulated at periods of 2–3 days. This appears to be associated with the interaction of the …

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The Recruitment Patterns Of An Estuarine Copepod: A Biological-Physical Model, Sanjay Gupta, Darcy J. Lonsdale, Dong-Ping Wang Jan 1994

The Recruitment Patterns Of An Estuarine Copepod: A Biological-Physical Model, Sanjay Gupta, Darcy J. Lonsdale, Dong-Ping Wang

Journal of Marine Research

A biological-physical model was developed to study the population growth of Coullana canadensis (Willey), a meroplanktonic copepod, in the Saco River estuary, Maine. The biological processes were derived from extensive laboratory and field data, and the physical processes were based on a comprehensive estuarine hydrodynamic model. The study found that the physical environment significantly altered the seasonal pattern of population growth from that predicted from the biological model. Nauplii were lost from the estuary due to flushing in spring and early summer, and thus, the timing of the peak in copepod recruitment was delayed until late summer. A …

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Phytoplankton Dynamics Associated With A Geostrophic Front: Ecological And Biogeochemical Implications, Hervé Claustre, Philippe Kerhervé, Jean Claude Marty, Louis Prieur, Christianne Videau, Jean-Henri Hecq Jan 1994

Phytoplankton Dynamics Associated With A Geostrophic Front: Ecological And Biogeochemical Implications, Hervé Claustre, Philippe Kerhervé, Jean Claude Marty, Louis Prieur, Christianne Videau, Jean-Henri Hecq

Journal of Marine Research

Using phytoplankton pigments as biomarkers, we investigated the relationship between the physical forcing and the resulting biological, ecological and biogeochemical properties of the geostrophic front of the Eastern Alboran Sea. (1) Typical frontal sites present biomass levels averaging 60 mg chl a m−2 (up to 100 mg m−2), whereas the adjacent zones (typical Atlantic and Mediterranean) are characterized by an average integrated chlorophyll biomass of 20 mg chl a m−2. (2) The phytoplankton biomass at front is diatom-dominated and differs markedly from the adjacent zones (typical Atlantic and Mediterranean), flagellate- and cyanobacteria-dominated. Therefore, high biomasses …

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Species Assemblages Of Leptocephali In The Subtropical Convergence Zone Of The Sargasso Sea, Michael J. Miller, James D. Mccleave Jan 1994

Species Assemblages Of Leptocephali In The Subtropical Convergence Zone Of The Sargasso Sea, Michael J. Miller, James D. Mccleave

Journal of Marine Research

Species assemblages of leptocephali are described in relation to density in the Subtropical Convergence Zone (STCZ) of the Sargasso Sea. Seven transects across fronts were made during four cruises in the late winter or early spring of 1983, 1985 and 1989. About 50 species from 13 families of eels were collected at 66 stations, but fewer than 10 species were abundant in all transects. Four oceanic species, two Anguilla species and Conger oceanicus appeared to be spawning in the STCZ. Leptocephali of most species whose adults inhabit the continental shelf were consistently large in size and were more abundant at …

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Parameter Space Exploration Of An Ocean General Circulation Model Using An Isopycnal Mixing Parameterization, William A. Gough, William J. Welch Jan 1994

Parameter Space Exploration Of An Ocean General Circulation Model Using An Isopycnal Mixing Parameterization, William A. Gough, William J. Welch

Journal of Marine Research

In this study we have employed statistical methods to efficiently design experiments and analyze output of an ocean general circulation model that uses an isopycnal mixing parameterization. Full ranges of seven inputs are explored using 51 numerical experiments. Fifteen of the cases fail to reach satisfactory equilibria. These are attributable to numerical limitations specific to the isopycnal model. Statistical approximating functions are evaluated using the remaining cases to determine the dependency of each of the six scalar outputs on the inputs. With the exception of one output, the approximating functions perform well. Known sensitivities, particularly the importance of diapycnal (vertical) …

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Generalized Two-Layer Models Of Ocean Circulation, Rick Salmon Jan 1994

Generalized Two-Layer Models Of Ocean Circulation, Rick Salmon

Journal of Marine Research

The assumption that surfaces of constant temperature and potential vorticity coincide leads to an exact, time-dependent reduction of the ideal thermocline equations in an ocean basin of arbitrary shape. After modifications to include forcing, dissipation, and the presence of the equator, these reduced equations form the basis for numerical models that are both more realistic and easier to solve than the conventional two-layer model.

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A Proposed Flux Constraint For Salt Fingers In Shear, Eric Kunze Jan 1994

A Proposed Flux Constraint For Salt Fingers In Shear, Eric Kunze

Journal of Marine Research

Towed ocean microstructure observations reveal that the temperature Cox number depends inversely on interface temperature-gradient Tz in the fingering-favorable thermohaline staircase east of Barbados. This implies fluxes independent of interface gradients. These conclusions are contrary to theoretical expectations from a finger Froude number stability criterion, |Δw|/N < 1.0: (i) Cox numbers independent of temperature gradient, and (ii) fluxes varying linearly with temperature gradient. We propose a hybrid wave/finger Froude number stability criterion, |(uz − wx)(wy − vz)|N2 ≤ 1.0 which reduces to Uz|Vw|/N2 ≤ 1.0 for salt sheets (δ/δx = 0, | Δw| = wy) aligned with background (internal-wave) shear Uz. …

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Calcium Carbonate Dissolution Rates In Hydrothermal Vent Fields Of The Guaymas Basin, Richard A. Lutz, Michael J. Kennish, Alan S. Pooley, Lowell W. Fritz Jan 1994

Calcium Carbonate Dissolution Rates In Hydrothermal Vent Fields Of The Guaymas Basin, Richard A. Lutz, Michael J. Kennish, Alan S. Pooley, Lowell W. Fritz

Journal of Marine Research

Analysis of bivalve shell fragments that were embedded in epoxy blocks, mounted on titanium stakes, and deployed by DSRV Alvin at 5 sites in the Southern Trough of the Guaymas Basin (27°00′N, 111°24.55′W; depth 2012 m) indicates significant variation of calcium carbonate dissolution in in situ exposures of more than 900 days. Arrays of shell fragments of six bivalve species (i.e., Bathymodiolus thermophilus, Calyptogena magnifica, Calyptogena sp., Corbicula fluminea, Crassostrea virginica and Mytilus edulis) were positioned −17 cm, −7 cm and −2.5 cm below the sediment-water interface and 2.5 cm, 7 cm and 17 cm above the sediment-water interface …

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Currents Under Land-Fast Ice In The Canadian Arctic Archipelago Part 2: Vertical Mixing, R. F. Marsden, R. G. Ingram, L. Legendre Jan 1994

Currents Under Land-Fast Ice In The Canadian Arctic Archipelago Part 2: Vertical Mixing, R. F. Marsden, R. G. Ingram, L. Legendre

Journal of Marine Research

During an acoustic Doppler current profiler (ADCP) study of the velocity field under land-fast ice, coincident CTD casts showed three instances of pronounced instability in the water column, immediately above and below the pycnocline. In this paper we demonstrate that the density inversions are associated with the passage of high frequency linear internal waves and finite amplitude waves. Contours of ADCP acoustic return intensity display pronounced vertical eddy-like features which may indicate overturning. A Richardson number calculation showed that even the most highly stratified portion of the pycnocline had sufficient vertical velocity shear to promote dynamic instability. Finally, we calculate …

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Currents Under Land-Fast Ice In The Canadian Arctic Archipelago Part 1: Vertical Velocities, R. F. Marsden, R. Paquet, R. G. Ingram Jan 1994

Currents Under Land-Fast Ice In The Canadian Arctic Archipelago Part 1: Vertical Velocities, R. F. Marsden, R. Paquet, R. G. Ingram

Journal of Marine Research

A 614 kHz acoustic Doppler current profiler was deployed through land-fast ice in Resolute Passage, in the Canadian Archipelago for 30 days in April and May 1992. It was demonstrated that in the mean, at tidal and at high frequencies the instrument was stable and aligned within 0.5° of vertical, permitting unambiguous measurement of the horizontal, and more importantly, the vertical velocity structure. The flow was dominated by tidal and high frequency (15 min period) oscillations. The K1 and M2 tidal currents were both approximately 10.0 cm s−1, oriented along-channel. The K1 component was constant …

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Individual Physiological Responses To Environmental Hypoxia And Organic Enrichment: Implications For Early Soft-Bottom Community Succession, Thomas L. Forbes, Valery E. Forbes, Michael H. Depledge Jan 1994

Individual Physiological Responses To Environmental Hypoxia And Organic Enrichment: Implications For Early Soft-Bottom Community Succession, Thomas L. Forbes, Valery E. Forbes, Michael H. Depledge

Journal of Marine Research

Infaunal inhabitants of coastal marine sediments occupy environments along a continuum from extremely food-rich, low-oxygen regions to food-poor habitats with relatively high levels of available oxygen. In organic-rich sediments, efficient utilization of available organic matter by deposit-feeding macrofauna may often be limited by the supply of oxygen. Specific feeding rate, growth, and production efficiency were measured on single individuals of the polychaete Capitella species 1 to determine whether previously measured declines in growth rates in response to hypoxia were due to decreased feeding, decreased conversion efficiency, or both. Under otherwise constant conditions, feeding rate was determined by the nitrogen content …

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Technological Change And Technology Strategy, Robert E. Evenson, Larry E. Westphal Jan 1994

Technological Change And Technology Strategy, Robert E. Evenson, Larry E. Westphal

Discussion Papers

No abstract provided.

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Demand For Children In Low Income Countries, T. Paul Schultz Jan 1994

Demand For Children In Low Income Countries, T. Paul Schultz

Discussion Papers

No abstract provided.

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Racial Differences In Bone Turnover Rate And Hyperparathyroidism In Hemodialysis Patients, Wendy Wei-Yue Lou Jan 1994

Racial Differences In Bone Turnover Rate And Hyperparathyroidism In Hemodialysis Patients, Wendy Wei-Yue Lou

Yale Medicine Thesis Digital Library

No abstract provided.

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Investigation Of The Mechanism Responsible For The Decreased Transcription Of The P53 Tumor Suppressor Gene In The Human Squamous Carcinoma Cell Line A253, Ho-Sheng Lin Jan 1994

Investigation Of The Mechanism Responsible For The Decreased Transcription Of The P53 Tumor Suppressor Gene In The Human Squamous Carcinoma Cell Line A253, Ho-Sheng Lin

Yale Medicine Thesis Digital Library

No abstract provided.

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Role Of Hypothalamic Neuropeptide Y In A Genetic Model Of Obesity : The Zucker Rat, Katherine E. Martin Jan 1994

Role Of Hypothalamic Neuropeptide Y In A Genetic Model Of Obesity : The Zucker Rat, Katherine E. Martin

Yale Medicine Thesis Digital Library

No abstract provided.

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Purification Of A Novel Mid-Region Fragment Of Parathyroid Hormone-Related Protein And Evidence Of Its Secretion By Three Different Cell Types, Katherine Elizabeth Dee Jan 1994

Purification Of A Novel Mid-Region Fragment Of Parathyroid Hormone-Related Protein And Evidence Of Its Secretion By Three Different Cell Types, Katherine Elizabeth Dee

Yale Medicine Thesis Digital Library

No abstract provided.

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Spatial And Temporal Distributions Of Sedimentary Chloropigments As Indicators Of Benthic Processes In Long Island Sound, Ming-Yi Sun, Robert C. Aller, Cindy Lee Jan 1994

Spatial And Temporal Distributions Of Sedimentary Chloropigments As Indicators Of Benthic Processes In Long Island Sound, Ming-Yi Sun, Robert C. Aller, Cindy Lee

Journal of Marine Research

Regular spatial and seasonal distribution patterns of sedimentary chloropigments occurred at 19 subtidal stations located in Long Island Sound (LIS) from MAY 1988 to APR 1989. Inventories of chloropigments were higher (2–10x) in western than central LIS, mirroring patterns of phytoplankton production in surface waters. Shallow water sediments (<25 m) received more chloropigments than deep stations (>25 m). Lateral resuspension and redistribution of particles, as shown by 234Th inventories, are partly responsible for these patterns. Seasonal variations of Chl-a inventories in LIS sediments follow the production pattern in the water column: higher values occur in spring and lower values in summer and fall. A time …

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Frictional Decay Of Abyssal Boundary Currents, Parker Maccready Jan 1994

Frictional Decay Of Abyssal Boundary Currents, Parker Maccready

Journal of Marine Research

A theory is presented to explain the observed longevity of abyssal boundary currents flowing along sloping topography. Typically such currents are many Rossby radii wide, and their energy is dominantly potential, residing in the broad upturn of isopycnals near the slope. The rate of decay of energy, on the other hand, is governed by the much smaller kinetic energy of the flow absorbed by the bottom boundary layer. The spin-down time is thus increased by a (possibly large) factor of PE/KE times that required to dissipate the kinetic energy alone. The ratio PE/KE is calculated from data on two sections …

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The Effect Of Current-Induced Stress Perturbation In A Coupled Atmosphere-Ocean Model, Lian Xie, Claes Rooth Jan 1994

The Effect Of Current-Induced Stress Perturbation In A Coupled Atmosphere-Ocean Model, Lian Xie, Claes Rooth

Journal of Marine Research

In the presence of surface currents, a stress perturbation at the air-sea interface is induced by the surface currents. It is directly correlated to the surface current pattern, and thus causes a feed-back effect in the sea-air system. This effect is studied for an equatorial sea-air system of the geometry of the equatorial Pacific Ocean by using a simple coupled atmosphere-ocean model. It is shown that the effect of the current-induced stress perturbation appears as a damping mechanism for the ocean circulation in general. However, in the presence of a zonally-asymmetric surface wind field, the stress perturbation associated with the …

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Aggregation And Sedimentation Processes During A Spring Phytoplankton Bloom: A Field Experiment To Test Coagulation Theory, Thomas Kiørboe, Claus Lundsgaard, Michael Olesen, Jørgen L. S. Hansen Jan 1994

Aggregation And Sedimentation Processes During A Spring Phytoplankton Bloom: A Field Experiment To Test Coagulation Theory, Thomas Kiørboe, Claus Lundsgaard, Michael Olesen, Jørgen L. S. Hansen

Journal of Marine Research

Spring diatom blooms in temperate waters are often terminated by aggregation of the cells into large flocs and subsequent mass sedimentation of the phytoplankton to the sea floor. The rate of aggregate formation by physical coagulation depends on the concentration of suspended particles, on the turbulent shear that makes particles collide, and on their stickiness (= probability of adhesion upon collision). During a mixed diatom bloom in a shallow Danish fjord, for 3 weeks we monitored the concentration and stickiness of suspended particles and the species composition of the phytoplankton at 2–3 d intervals and we estimated the turbulent shear …

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Internal Tidal Bores In The Nearshore: Warm-Water Fronts, Seaward Gravity Currents And The Onshore Transport Of Neustonic Larvae, Jesus Pineda Jan 1994

Internal Tidal Bores In The Nearshore: Warm-Water Fronts, Seaward Gravity Currents And The Onshore Transport Of Neustonic Larvae, Jesus Pineda

Journal of Marine Research

Nearshore temperature fluctuations are associated with energetic cross-shore two-way flows that influence the onshore transport of neustonic larvae. Water temperature near the surface and bottom at two nearshore stations off southern California (6 and 15 m water depth, respectively) can drop sharply and subsequently rise. Two or more consecutive drops and rises can occur at diurnal or semidiurnal periodicities. The temperature increases may be accompanied by energetic seaward bottom currents together with sharp-edged warm-water fronts. (Warm-water fronts are defined here as linear seasurface features dividing parcels of water of different temperature.) Shoreward-moving surface fronts divided bodies of water of different …

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Flow Along And Across The Aleutian Ridge, R. K. Reed, P. J. Stabeno Jan 1994

Flow Along And Across The Aleutian Ridge, R. K. Reed, P. J. Stabeno

Journal of Marine Research

During a synoptic hydrocast survey in September 1993 near the Aleutian Islands, net northward flow of Alaskan Stream water occurred through deep passes near 180 and 172W. This inflow (≈4 × 106 m3 s−1) was the source of the eastward flow in the Bering Sea north of the islands. The eastward flow, however, was weaker and more convoluted than the stream flow (≈7 × 106 m3 s−1, referred to 1000 db) south of the islands.

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Signatures Of Stirring And Mixing Near The Gulf Stream Front, G. L. Hitchcock, T. Rossby, J. L. Lillibridge Iii., E. J. Lessard, E. R. Levine, D. N. Connors, K. Y. Børsheim, M. Mork Jan 1994

Signatures Of Stirring And Mixing Near The Gulf Stream Front, G. L. Hitchcock, T. Rossby, J. L. Lillibridge Iii., E. J. Lessard, E. R. Levine, D. N. Connors, K. Y. Børsheim, M. Mork

Journal of Marine Research

In October, 1986 the surface waters adjacent to the Gulf Stream front were surveyed with an undulating profiler to describe the finescale structure of the mixed layer. The profiler was a Seasoar equipped with a CTD and fluorometer. The survey first defined the structure of a cyclonic eddy which resembled frontal eddies of the South Atlantic Bight in sea surface temperature imagery. The Seasoar transects revealed, however, that the cyclonic eddy lacked a cold dome typically seen in frontal eddies. Farther downstream the Seasoar defined the structure of streamers of Gulf Stream and Shelf water wrapped about the southern edge …

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Vortex Pair Model Of Langmuir Circulation, G. T. Csanady Jan 1994

Vortex Pair Model Of Langmuir Circulation, G. T. Csanady

Journal of Marine Research

Accumulating evidence shows spacing and length of surface convergences associated with Langmuir circulation to be random variables, their strength also variable, their lifetime limited. Analysis of several sets of quantitative observations reveals the probability distribution of windrow spacing to be lognormal. This suggests generation of surface convergences at random times and locations on the sea surface. Moving shear stress anomalies, under wind gusts or breaking long waves, are capable of generating surface convergence in their wakes, and are the type of random event likely responsible for the stochastic properties of windrows. The generation mechanism envisaged is a “forced” version of …

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Measurements Of Internal Wave Band Eddy Fluxes Above A Sloping Bottom, Hans Van Haren, Neil Oakey, Chris Garrett Jan 1994

Measurements Of Internal Wave Band Eddy Fluxes Above A Sloping Bottom, Hans Van Haren, Neil Oakey, Chris Garrett

Journal of Marine Research

The boundary layer near a sloping bottom may have a major influence on the ocean's interior density structure (due to “boundary mixing”) and on its circulation (because of the arrest of the Ekman layer by buoyancy forces). As a first attempt to measure eddy fluxes of momentum and buoyancy, in order to quantify the mixing in this region, we have carried out a 5-day pilot experiment on a sloping side of Emerald Basin on the Scotian Shelf. A moored upward-looking 1.2 MHz ADCP and a thermistor chain mounted along its vertical axis returned analyzable data between 8 and 17 m …

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Set-Down Computations Over An Arbitrarily Inclined Plane Bed, Ulf Torsten Ehrenmark Jan 1994

Set-Down Computations Over An Arbitrarily Inclined Plane Bed, Ulf Torsten Ehrenmark

Journal of Marine Research

A perturbation theory, for waves on a perfect fluid in a wedge-shaped domain, is used to derive integral expressions for set-down valid up to the breaker line for arbitrary wedge angles α. Computations are carried out for a set α = π/2N, (N = 2,3,…,7,15) using a generalized Simpson quadrature and these confirm that existing theory underestimates the set-down by a factor which increases with the wedge angle. Curve fitting techniques are used to deduce a modification of the formula given by Longuet-Higgins and Stewart (1963) which can be universally implemented to estimate set-down just seaward of …

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A Modelling Study Of Discontinuous Biological Irrigation, Bernard P. Boudreau, Roberta L. Marinelli Jan 1994

A Modelling Study Of Discontinuous Biological Irrigation, Bernard P. Boudreau, Roberta L. Marinelli

Journal of Marine Research

Irrigation of infaunal dwellings can lead to significant alteration of solute distributions in sediments. As a result, sediment-seawater fluxes of nutrients and dissolved carbon are greatly enhanced, and the biology of benthic communities is affected. The most realistic mathematical representation of irrigation and its effect on sediment geochemistry is Aller's (1980) cylinder model. One critical assumption of this model is that burrows are irrigated continually, and that burrow water solute concentrations are identical to overlying water concentrations at all times. However, the vast majority of infaunal tube- and burrow-dwelling organisms irrigate periodically, i.e. in an on/off cycle. During periodic irrigation, …

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Instability Waves In The Gulf Stream Front And Its Thermocline Layer, Sang-Ki Lee, G. T. Csanady Jan 1994

Instability Waves In The Gulf Stream Front And Its Thermocline Layer, Sang-Ki Lee, G. T. Csanady

Journal of Marine Research

We carried out linear instability calculations on a three layer Gulf Stream front model in an attempt to elucidate the interaction of the thermocline layer with surface slopewater shoreward of the front. The basic state is geostrophic balance and constant potential vorticity in the two active layers, but the perturbations are ageostrophic. We found the flow to be unstable to long wave perturbations, the wavelength of the most unstable wave to be of the order of 10 radii of deformation. The instability is mainly baroclinic, 75–85% of the energy supply to the growing perturbation coming from basic flow potential energy. …

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The Coupling Of Regional Cerebral Blood Flow To Neuronal Activity Is In Part Mediated By Nitric Oxide And Adenosine, Michael G. Kaiser Jan 1994

The Coupling Of Regional Cerebral Blood Flow To Neuronal Activity Is In Part Mediated By Nitric Oxide And Adenosine, Michael G. Kaiser

Yale Medicine Thesis Digital Library

No abstract provided.

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