Antibiotics are essential for control of bacterial diseases of plants, especially fire blight of pear and apple and bacterial spot of peach. Streptomycin is used in several countries; the use of oxytetracycline, oxolinic acid and gentamicin is limited to only a few countries. Springtime antibiotic sprays suppress pathogen growth on...
Declining abundance of Chinook Salmon Oncorhynchus tshawytscha across the Pacific Northwest is an issue of great concern ecologically, culturally, and economically. Growth during the first summer is vitally important for juvenile Chinook Salmon, as it influences not only life history decisions (to smolt or not to smolt) but also subsequent...
Ammonia (NH₃)-oxidizing bacteria (AOB) and thaumarchaea (AOA) co-occupy most soils, yet no short-term growth-independent method exists to determine their relative contributions to nitrification in situ. Microbial monooxygenases differ in their vulnerability to inactivation by aliphatic n-alkynes, and we found that NH₃ oxidation by the marine thaumarchaeon Nitrosopumilus maritimus was unaffected...
Expectations for technology proficiency in counseling and counselor education have increased; nevertheless, very little information is available in the counseling literature which describes how to effectively evaluate online resources from a design and utility standpoint. This study provides a model for such assessments, employing an affordable small scale usability study...
Despite its very low oral bioavailability and rapid elimination, multiple reports of unexpectedly high bisphenol A (BPA) concentrations in the serum of pregnant mothers or cord blood have raised questions about BPA exposures during pregnancy. Thirty healthy pregnant women recruited to the study were evaluated for total BPA exposure over...
BACKGROUND: Chronic kidney disease (CKD) and hyperuricemia often coexist and both conditions are increasing in prevalence in the U.S., although their shared role on cardiovascular risk remains highly debated.
STUDY DESIGN: Cross-sectional and longitudinal
SETTING AND PARTICIPANTS: Participants in the National Health and Nutrition Examination Survey (NHANES) from 1988 to...
Subtropical marine stratus clouds regulate coastal and global climate, but future trends in these clouds are uncertain. In coastal Southern California (CSCA), interannual variations in summer stratus cloud occurrence are spatially coherent across 24 airfields and dictated by positive relationships with stability above the marine boundary layer (MBL) and MBL...
Infrared radiometers, photographs, and a multispectral
scanner were used in a remote sensing study of the ocean off
Oregon during the summer of 1969. Upwelling appeared on
infrared temperature maps as a zone of cold water along the
coast and Columbia River water appeared as a warm water
"plume". Sharp...
Sixty-day simulations of flow on the Oregon continental shelf are performed using the Blumberg and Mellor sigma coordinate, primitive equation model. The model is two-dimensional (an across-shelf section) with high spatial resolution and realistic shelf topography. Forcing consists of surface heat flux, either hourly or low-pass filtered wind stress, and...
Time-dependent upwelling on the Oregon continental shelf is studied with a two-dimensional approximation, that is, spatial variations across-shelf and with depth, using the Blumberg–Mellor, finite-difference, stratified, primitive equation model. The time-dependent response of a coastal ocean at rest to constant, upwelling favorable, wind stress is examined. Topography and stratification representative...
Data from the SeaWinds scatterometer on the
QuikSCAT satellite are used to estimate upwelling around
Cabo Frio, Brazil, due to Ekman transport and Ekman
pumping. The region close to shore (up to 200 km from the
coast) is characterized by negative wind stress curl
(upwelling favorable) year-round, with maximum values...
High‐resolution three‐dimensional (3‐D) seismic reflection data acquired on the R/V Thomas G. Thompson in 2000 reveal a pair of bottom simulating reflections (BSRs) across a broad region of southern Hydrate Ridge, offshore Oregon. The primary BSR (BSRp) is a regionally extensive reflection that lies 120–150 m below seafloor and exhibits...
In flight through a wave cloud during SUCCESS on 2 May 1996, simultaneous forward- and aft- facing NOy inlets were used to infer the amount of condensed-phase NOy present on ice particles that were up to a few minutes old. Condensed-phased amounts were 25-75 pptv, or 10-20% of gas-phase NOy....
Uptake of [14C]glycine by various size fractions of natural plankton communities was measured to determine if phytoplankton can compete effectively with other members of the plankton community for the free amino acids in seawater. The simultaneous occurrence of glycine uptake, plant pigments, and photosynthetic activity in the same size fractions,...
The stable isotope 15N was used to measure nitrogen uptake in the coastal upwelling region off Oregon and Washington, USA, where nitrate concentrations in the surface water ranged from 0.7 to 49.1 μM. Nanoplankton biomass (1 to 10 pm) was relatively more abundant at low-nitrate stations, while netplankton biomass (10...
A variety of macromolecules labeled with FITC (fluorescein isothiocyanate), including
carbohydrates (dextran) and proteins (ferritin, casein, albumin, concavalin A), spanning a range of
molecular weights from 55 to 2000 kD, were actively ingested by marine heterotrophic flagellates at
substrate concentrations of 1 to 10 mg/L. The uptake capacity for the...
Raspberry and blackberry (Rubus sp.) plantings have a relatively low nutrient requirement compared with many other perennial fruit crops. Knowledge of annual accumulation of nutrients and periods of rapid uptake allows for better management of fertilization programs. Annual total nitrogen (N) accumulation in the aboveground plant ranged from 62 to...
In this work, we revisit the upscaling process of diffusive mass transfer of a solute undergoing a homogeneous reaction in porous media using the method of volume averaging. For linear reaction rate kinetics, the upscaled model exhibits a vis-à-vis correspondence with the mass transfer governing equation at the microscale. When...
Relative humidity (RH) measurements acquired in orographic wave cloud and cirrus environments are used to investigate the temperature‐dependent RH required to nucleate ice crystals in the upper troposphere, RHnuc(T). High ice‐supersaturations in clear air—conducive to the maintenance of aircraft contrails yet below RHnuc and therefore insufficient for cirrus formation—are not...
The response of the upper ocean to westerly wind forcing in the western equatorial Pacific was modeled by means of large-eddy simulation for the purpose of comparison with concurrent microstructure observations. The model was initialized using currents and hydrography measured during the Coupled Ocean–Atmosphere Response Experiment (COARE) and forced using...
A strong, isolated October storm generated 0.35–0.7 m s⁻¹ inertial frequency currents in the 40-m deep mixed layer of a 300 km×300 km region of the northeast Pacific Ocean. The authors describe the evolution of these currents and the background flow in which they evolve for nearly a month following...
Zonal and meridional Seasoar sections centered at 1°50’S, 156°06’E were repeated >30 times in three 20-day periods between November 13, 1992, and February 15, 1993. Both sections were 130 km long, and sampling depth was 0–280 m, with a vertical resolution of ~2 dbar (2 x 104 Pa) and a...
This paper provides a cross-layer analysis of uplink performance in femtocell networks. It characterizes the uplink physical
interference in femtocell networks and studies its impact on the delay and data loss rate of constant-bit-rate (CBR) traffic, as well
as on the maximum achievable femto-user throughput. Our work derives data-link layer...
Sporulation is an important strategy for certain bacterial species within the phylum Firmicutes to survive longer periods of time in adverse conditions. All spore-forming bacteria have two phases in their life; the vegetative form, where they can maintain all metabolic activities and replicate to increase numbers, and the spore form,...
Zebrafish are a powerful model organism to study disease. Like other animal models, Danio rerio colonies are at risk of pathogenic infection. Microsporidia, a group of intracellular fungus-like parasites, are one potential threat. Microsporidian spores germinate and spread causing pathological changes in the central nervous system, skeletal muscle, and other...
Imaging Ca²⁺ dynamics in living systems holds great
potential to advance neuroscience and cellular biology. G-GECO1.1
is an intensiometric fluorescent protein Ca²⁺-biosensor with a Thr-Tyr-Gly chromophore. The protonated chromophore emits green
upon photoexcitation via excited-state proton transfer (ESPT). Upon
Ca²⁺ binding, a significant population of the chromophores becomes
deprotonated. It...
Background: Recent mapping of eukaryotic transcriptomes and spliceomes using massively parallel RNA sequencing (RNA-seq) has revealed that the extent of alternative splicing has been considerably underestimated. Evidence also suggests that many pre-mRNAs undergo unproductive alternative splicing resulting in incorporation of in-frame premature termination codons (PTCs). The destinies and potential functions...
Despite nutrient-depleted conditions, coral reef waters harbor abundant and diverse microbes; as major agents of microbial mortality, viruses are likely to influence microbial processes in these ecosystems. However, little is known about marine viruses in these rapidly changing ecosystems. Herewe examined spatial and short-term temporal variability in marine viral abundance...
Purpose: We examined the prevalence and correlates of unmet assistance need with respect to activities of daily living (ADLs) and instrumental activities of daily living (IADLs) among older American Indians.
Design and Methods: Data for our analyses were collected in 2006–2008 as part of the Native Elder Care Study, a...
In 2012, heads of local law enforcement agencies in Benton County, Oregon, contacted researchers at Oregon State University to discuss a problem: a sharp rise in the amount of contact between police and suspects displaying symptoms of mental illness. This initial contact led to an ongoing collaborative examination of the...
Experiments conducted on the Oregon continental shelf in June 1979 indicate that the boundary layer
flow at the seafloor was hydrodynamically smooth. Fine-resolution velocity profiles are used to test the
assumption that the flow behaved like a universally similar, neutrally buoyant flow over a smooth wall.
The non-dimensional thickness of...
Suspended metallic carbon nanotubes (m-CNTs) exhibit a remarkably large transport gap that can exceed 100 meV. Both experiment and theory suggest that strong electron-electron interactions play a crucial role in generating this electronic structure. To further understand this strongly-interacting system, we have performed electronic measurements of suspended m-CNTs with known...
Disturbance events strongly affect the composition, structure, and function of forest ecosystems; however, existing US land management inventories were not designed to monitor disturbance. To begin addressing this gap, the North American Forest Dynamics (NAFD) project has examined a geographic sample of 50 Landsat satellite image time series to assess...
Across Western Europe, unions have increasingly engaged in staging general strikes against governments since 1980. This increase in general strikes is puzzling as it has occurred at the same time as economic strikes have been on the decline. We posit that theories developed to explain economic strikes hold little explanatory...
Microphysical and chemical aerosol measurements collected during DYCOMS‐II research flights in marine stratocumulus clouds near San Diego in 2001 were used to evaluate the partitioning of 18 organic and elemental components between droplet residuals and unactivated particles. Bulk submicron particle (between 0.2 and 1.3 μm dry diameter) and droplet residual...
The 2014 Working Group on California Earthquake Probabilities
(WGCEP14) present the time-independent component of the Uniform California
Earthquake Rupture Forecast, Version 3 (UCERF3), which provides authoritative
estimates of the magnitude, location, and time-averaged frequency of potentially
damaging earthquakes in California. The primary achievements have been to relax
fault segmentation and...
Current AASHTO-LRFD specifications use many disparate design provisions to establish live load demands in bridge decks. As an example, approximately 17% of Chapter 4 addresses the analysis of decks. One of the AASHTO-LRFD analysis methods for decks uses an orthotropic plate model. The present AASHTO-LRFD orthotropic plate model has a...
Ungulates exert a strong influence on the composition and diversity of vegetation communities. However, little is known about how ungulate browsing pressure interacts with episodic disturbances such as fire and stand thinning. We assessed shrub responses to variable browsing pressure by cattle and elk in fuels treated (mechanical removal of...
Gene regulatory networks are commonly used for modeling biological processes and revealing underlying molecular mechanisms. The reconstruction of gene regulatory networks from observational data is a challenging task, especially considering the large number of players (e.g. genes) involved and the small number of biological replicates available for analysis. Herein, we...
Following trends in higher education that emphasize quantitative analytical approaches to assess educational outcomes, academic libraries are increasingly attempting to quantify their impacts on student learning and demonstrate their value to the university’s educational mission. By applying learning analytics techniques to library use and instructional data, libraries have especially focused...
Following trends in higher education that emphasize quantitative analytical approaches to learn about educational outcomes, academic libraries are increasingly attempting to quantify their impacts on student learning and demonstrate their value to the university’s educational mission. By applying learning analytics techniques to library use and instructional data, libraries have especially...
A network of autonomous underwater hydrophones is used to monitor acoustic activity associated with Hunga Ha'apai-Hunga Tonga volcano during a period of 15 months. The data provide a continuous record spanning a surtseyan eruption (VEI 2) in March of 2009, which input ~10¹³ J of acoustic energy into the ocean...
Longleaf pine (Pinus palustris Mill.) forests are characterized by unusually high understory plant species diversity, but models describing understory ground cover biomass, and hence fuel load dynamics, are scarce for this fire-dependent ecosystem. Only coarse scale estimates, being restricted on accuracy and geographical extrapolation, are available. We analyzed the dynamics...
Piñon (Pinus spp.) and juniper (Juniperus spp.) trees are reduced to restore native vegetation and avoid severe fires where they have expanded into sagebrush (Artemisia tridentata Nutt.) communities. However, what phase of tree infilling should treatments target to retain desirable understory cover and avoid weed dominance? Prescribed fire and tree...
In the blink of an eye, unconscious bias was visible to me, an African American. A man saw my face as I walked into the store and unconsciously checked his wallet. On the street, a woman catches my eye a half block away and moves her purse from the handle...
Understanding the precise role of the immune system in cancer has been hindered by the complexity of the immune response and challenges in measuring immune cell types in health and disease in the context of large epidemiologic studies. In this review, we present the rationale to study immunity in cancer...
In environmental management, companies must respond to myriad needs and pressures from
stakeholders such as buyers, regulators, communities and NGOs. While researchers recognize
that these stakeholder entities have different saliency and influences over a focal firm, the
influences from multiple stakeholders are often aggregated as a single factor, overlooking
differences...
The relationship between livelihoods and forest use is one of the main challenges facing wildlife and habitat conservation in developing countries. Poor residents in forest-adjacent areas are typically perceived to be the main forest users, with use often deemed illegal. However, there is still a limited understanding of livelihood constraints...
This study investigated the informal science education (ISE) field to determine whether it currently functions as an effective community of practice. Research questions included: How do professionals describe and self-identify their practice, including what missions, goals and motivating factors influence their professional work? What challenges do they face and how...
Background: Statins substantially reduce cardiovascular disease risk and are generally well-tolerated, but many patients discontinue therapy. A better understanding of the characteristics of current and former statin users may be helpful for formulating strategies to improve long-term adherence.
Objective: The Understanding Statin Use in America and Gaps in Education (USAGE)...
Ecohydrological connectivity is a system level property that results from the linkages in the networks of water transport through ecosystems, by which feedbacks and other emergent system behaviours may be generated. We created a system dynamics model that represents primary ecohydrological networks to examine how connectivity between ecosystem components impacts...
This study reviews the experience of cooperation in five international river basins, focusing on the perceptions of risks and opportunities by country decision makers responding to a specific prospect of cooperation, and the effects of risk reduction and opportunity enhancement on the cooperation process. We explore the following five categories...
In a multilevel study to determine limits to underplanted conifer seedling growth, Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco), grand fir (Abies grandis (Dougl. ex D. Don) Lindl.), western redcedar (Thuja plicata Donn ex D. Don), and western hemlock (Tsuga heterophylla (Raf.) Sarg.) seedlings were planted beneath second-growth Douglas-fir stands that had...
Intracellular pH (pH(i)) imaging is of paramount importance for life sciences. In this work, we implement the ultrafast electronic and stimulated Raman spectroscopies to unravel the fluorescence mechanism of an excitation-ratiometric pH(i) indicator in basic aqueous solution. After photoexcitation of the pH(i) indicator HPTS, a hidden charge-transfer (CT) state following...
Multiple factors are known to influence student success in higher education. Barriers to postsecondary success for underrepresented STEM students are numerous and well documented. We detail an exploratory study of STEM faculty notions of successful students and the instructional practices they employ to cultivate student success. We use a conceptual...
Unconditioned responding (UCR) to a naturally aversive stimulus is associated with defensive responding to a conditioned threat cue (CS+) and a conditioned safety cue (CS-) in trauma-exposed individuals during fear acquisition. However, the relationships of UCR with defensive responding during extinction training, posttraumatic stress disorder (PTSD) symptom severity, and fearful...
Uncertainty relations provide constraints on how well the outcomes of incompatible measurements can be predicted, and as well as being fundamental to our understanding of quantum theory, they have practical applications such as for cryptography and witnessing entanglement. Here we shed new light on the entropic form of these relations,...
Continued stock declines in marine fisheries have resulted in a search for more risk-averse management approaches. In response, the Sustainable Fisheries Act of 1996 mandates habitat protection, bs catch reduction, and stock rebuilding. These changes emphasize precaution, and imply a shift in focus from maximizing yields to minimizing ecological impacts...
The methods for conducting reductionist ecological science are well known and widely used. In contrast, those used in the synthesis of ecological science (i.e., synthesis science) are still being developed, vary widely, and often lack the rigor of reductionist approaches. This is unfortunate because the synthesis of ecological parts into...
Whole ecosystem carbon dioxide (CO₂) exchange estimated with the eddy covariance (EC) technique has been central to studies on the responses of terrestrial ecosystems to disturbance and intra‐annual and interannual variations in climate, but challenges exist in understanding and reducing the uncertainty in estimates of net ecosystem exchange (NEE) of...
For 30 years, the pathogen Haplosporidium nelsoni (MSX) has been causing serious mortalities of eastern oysters Crassostrea virginica in the Delaware and Chesapeake bays. Its life cycle is largely unknown, and methods for control are wanting. Breeding of resistant eastern oyster strains, at this time, offers the best hope for...
Flux estimates show that upward mixing of the deep-water nitrate pool accounts for more than 85% of the total new nitrogen input to the euphotic zone of Crater Lake. Because measured primary productivity (360 mg C m-2 d-1) is 10–30 times higher than a level supported solely by the input...
Graphis robertusii Bárcenas-Peña, Herrera-Campos y Miranda es descrita por primera vez para la selva alta perennifolia de Los Tuxtlas, Veracruz. Es una especie conspicua caracterizada por lirelas erumpentes con margen talino lateral, labios no estriados blancos pruinosos, excípulo completamente carbonizado, himenio insperso, esporas transversalmente septadas y ácidos estíctico, salazínico y...
Ambient ultraviolet-B radiation can harm amphibian eggs, larvae and adults. However, some amphibians avoid UV-B radiation when given the opportunity. The strawberry poison dart frog, Oophaga pumilio, is diurnal and males vocalize throughout the day in light gaps under forest canopies that expose them to solar radiation. Previous studies have...
Eight spontaneous orocutaneous papillomas of adult, wild-caught brown bullheads Ictalurus
nebulosus and 4 anatomically matching control tissue samples were examined by electron
microscopy. Ultrastructural characteristics of normal and neoplastic Malpighian epithelial cells were
compared and neoplastic cells were described. Normal Malpighian epithelial cells of brown bullheads
were similar to those...
In this paper, we report a fiber-optic carbon dioxide (CO₂) near-infrared (IR) absorption sensor with only 8-cm sensing length that is coated with nanoporous metalorganic framework material Cu-BTC (BTC = benzene-1,3, 5-tricarboxylate). The multimode optical fiber was etched by hydrofluoric acid to remove the cladding and part of the core,...
Intraexciton transitions in semiconductor quantum wells are modulated by strong and tunable few-cycle terahertz pulses. Time-resolved terahertz-pump and optical-probe measurements demonstrate that the 1s heavy-hole and light-hole exciton resonances undergo large-amplitude spectral modulations when the terahertz radiation is tuned near the 1s–2p intraexciton transition. The strong nonlinear optical transients exhibit...
The U.S. Forest Service administers the world's largest forestry research organization. From its modest
beginning in 1876, some 30 years before the United States national forest system was established, the research
branch has devoted its effort to meet current and future information needs of the forestry community of the
United...
We provide the first evidence on the causal effect of border enforcement on the full spatial distribution of Mexican immigrants to the United States. We address the endogeneity of border enforcement with an instrumental variables strategy based on administrative delays in budgetary allocations for border security. We find that 1,000...
Of 14 transgenic poplar genotypes (Populus tremula × Populus alba) with antisense 4-coumarate:coenzyme A ligase that were grown in the field for 2 years, five that had substantial lignin reductions also had greatly reduced xylem-specific conductivity compared with that of control trees and those transgenic events with small reductions in...
A novel method of copper indium diselenide nanoparticle
(CuInSe₂ NP) synthesis using a two-step, continuous flow,
solar microreactor is reported here. This method allows for
exceedingly fast heating and short reaction times using only
radiative heat transfer from simulated, concentrated solar
radiation. Chalcopyrite and sphalerite CuInSe₂ phases have
both been...
The distributed-microstructure model for the flow of single phase
fluid in a partially fissured composite medium due to Douglas-Peszyńska-Showalter [12] is extended to a quasi-linear version. This model contains the
geometry of the local cells distributed throughout the medium, the flux exchange
across their intricate interface with the imbedded fissure...
Qualitative two-phase flow regime data are obtained from high-speed visualization of condensing flows of R-134a at mass fluxes from 75 to 150 kg m−2 s−1 and quality from 0.1 to 0.8 in square microchannels (DH = 0.84 mm) cooled from a single side. Superheated R-134a is distributed into multiple parallel microchannels and then partially condensed, using...
Understanding the genetic basis of pathogen susceptibility in various crop plants is crucial to increasing the stability of food, feed, and fuel production. Varietal differences in defence responses provide insights into the mechanisms of resistance and are a key resource for plant breeders. To explore the role of salicylic acid...
Heliotropium foliatum and Tournefortia humilis are transferred to Euploca Nutt. respectively as Euploca foliata comb. n. and Euploca humilis comb. n. A collection from Guyana has been recently identified as Euploca humistrata, a species previously considered a Brazilian endemic. A collection from French Guiana documents for the first time the...
Two myxozoan species were observed in the kidney of topsmelt, Atherinops affinis, during a survey of parasites of estuarine fishes in the Carpinteria Salt Marsh Reserve, California. Fish collected on 3 dates in 2012 and 2013 were sectioned and examined histologically. Large extrasporogonic stages occurred in the renal interstitium of...
Background: There is evidence that seasonal variation in depressive symptoms is common in the population. However, research is limited by a reliance on longterm retrospective methods. Methods: Seasonal patterns were tested in two samples of community participants recruited in separate prospective studies in the Midwestern (n = 556 males/females) and...
Marine sponges are vital components of benthic and coral reef ecosystems, providing shelter and nutrition for many organisms. In addition, sponges act as an essential carbon and nutrient link between the pelagic and benthic environment by filtering large quantities of seawater. Many sponge species harbor a diverse microbial community (including...
A pair of hydrographic sections, one north and one south of Cape Blanco at 42.9N, was sampled in five summers (1998–2000 and 2002–2003). The NH line at 44.6N lies about 130 km south of the Columbia River, and spans a relatively wide shelf off Newport, Oregon. The CR line at...
Cell lines were established from spleen and heart tissues of a juvenile white sturgeon Acipenser transmontanus and designated WSS-2 and WSH-1, respectively. Isoenzyme analyses of both lines confirmed their host of origin. Both lines were hypotetraploid and possessed micro- and macrochromosomes. The modal chromosome number for the WSS-2 line was...
Retreating glaciers and the periglacial areas they vacate for organismal colonization produce a harsh environment of extreme radiation, nutrient limitations, and temperature oscillations. They provide a model system for studying mechanisms that drive establishment and early assembly of communities. Here, we synthesize more than twenty years of research at the...
A physically based hydrology model is used to produce time series for the period 1916–2003 of evapotranspiration (ET), runoff, and soil moisture (SM) over the western United States from which long-term trends are evaluated. The results show that trends in ET in spring and summer are determined primarily by trends...
Chronic heavy alcohol consumption is a risk factor for cortical bone fractures in males. The increase in fracture
risk may be due, in part, to reduced bone quality. Intracortical (osteonal) bone remodeling is the principle
mechanism for maintaining cortical bone quality. However, it is not clear how alcohol abuse impacts...
Fluxes of sulphur dioxide to wheat were measured over two growing seasons. The deposition velocity, vg, depended primarily on affinities of surfaces for SO2 and varied from less than 0.1 to about 1.5cms−1. Stomata were an important sink, and diurnal changes in stomatal resistance accounted for most of the variation...
We present observations from deployments of a microstructure turbulence instrument
(the Towed Microstructure and Auxiliary Sensor Instrument) aboard a pumping profiling
vehicle (the Lamont Pumping SeaSoar) towed behind a research vessel at the New
England shelf break front in August 2002. From these we determined coincident fine-scale
vertical eddy diffusivity...
Turbulent mixing of salt is examined in a shallow salt wedge estuary with strong fluvial and tidal forcing. A numerical model of the Merrimack River estuary is used to quantify turbulent stress, shear production, and buoyancy flux. Little mixing occurs during flood tides despite strong velocities because bottom boundary layer...
Pacific Water flows across the shallow Chukchi Sea before reaching the Arctic Ocean, where it is a source of heat, freshwater, nutrients, and carbon. A substantial portion of Pacific Water is routed through Barrow Canyon, located in the northeast corner of the Chukchi. Barrow Canyon is a region of complex...
An experimental study was undertaken to better understand the turbulent flow characteristics
within a randomly packed porous bed. A relatively low aspect ratio bed
(bed width to spherical solid phase particle diameter of 4.67) with the fluid phase
refractive index matched to that of the solid phase was used to...
A 38-day, 5990-cast microstructure study on the equator performed
during the onset of the 1991-1993 El Nino shows the effect on small-scale activity
at 140°W of an equatorial Kelvin wave. By using two ships, data were taken
continuously from November 4 to December 12, 1991, near the National Oceanic
and...
An investigation of nocturnal intermittent turbulence during the Cooperative Atmosphere Surface Exchange Study in 1999 (CASES-99) revealed three turbulence regimes at each observation height: 1) regime 1, a weak turbulence regime when the wind speed is less than a threshold value; 2) regime 2, a strong turbulence regime when the...
Field observations of turbulence and sediment suspension in the nearshore wave bottom boundary layer obtained during the Duck94 field experiment on the North Caroline coast showed the generation of near-bed turbulence to be highly intermittent. The intermittent nature of the flow was examined by applying homogeneous isotropic turbulence laws over...
Turbulence quantities are analyzed from nine months of data collected on the floor of a valley where nocturnal cold pools are frequent. Often the speed of the vector-averaged wind over the night is less than 0.5 m s−1 (near-calm winds) with no preference for wind direction. The quantity of such...
A large-eddy simulation study was performed to characterize turbulence in sparse, row-oriented canopies. This was accomplished by simulating a set of heterogeneous row-oriented canopies with varying row vegetation density and spacing. To determine the effects of heterogeneity, results were compared to horizontally homogeneous canopies with an equivalent ‘effective’ leaf area...
Direct numerical simulations (DNS) of a shear layer with salt-fingering-favorable stratification have been performed for different Richardson numbers Ri and density ratios R[subscript]p. In the absence of shear (Ri = oo), the primary instability is square planform salt fingering, alternating cells of rising and sinking fluid. In the presence of...
Although the process of restratification of the ocean surface layer at the equator following nighttime convection is similar in many ways to the process at midlatitudes, there are important differences. A composite day calculated from 15 days of consistent conditions at 140°W on the equator was compared with midlatitude observations...
The importance of leads, sea ice motion, and frazil ice on the wintertime ocean
Boundary layer was examined by using a large-eddy simulation turbulence model coupled to a
thermodynamic slab ice model. Coupling was achieved through exchange coefficients that
accounted for the differing diffusion rates of heat and salinity. Frazil...
Motivated by the tendency of high-Prandtl-number fluids to form sharp density interfaces, the authors investigate the evolution of Holmboe waves in a stratified shear flow through direct numerical simulation. Like their better-known cousins, Kelvin–Helmholtz waves, Holmboe waves lead the flow to a turbulent state in which rapid irreversible mixing takes...
In the low Richardson number shear flow above the Pacific Equatorial Undercurrent, a single vertical microstructure profile intersected the overturning crest of a packet of high horizontal wavenumber waves. The observed dissipation rates within the overturning wave were so high that if they were representative of the volume-averaged rate, the...