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2002

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Articles 121 - 145 of 145

Full-Text Articles in Oceanography and Atmospheric Sciences and Meteorology

Hydrographic Conditions Off Northern Chile During The 1996-1998 La Niña And El Niño Events, Jose Luis Blanco, Mary-Elena Carr, Andrew C. Thomas, P. Ted Strub Jan 2002

Hydrographic Conditions Off Northern Chile During The 1996-1998 La Niña And El Niño Events, Jose Luis Blanco, Mary-Elena Carr, Andrew C. Thomas, P. Ted Strub

CCPO Publications

The evolution of oceanographic conditions in the upwelling region off northern Chile (18°-24°S) between 1996 and 1998 (including the 1997-1998 El Niño) is presented using hydrographic measurements acquired on quarterly cruises of the Chilean Fisheries Institute, with sea surface temperature (SST), sea level, and wind speeds from Arica (18.5°S), Iquique (20.5°S), and Antofagasta (23.5°S) and a time series of vertical temperature profiles off Iquique. Spatial patterns of sea surface temperature and salinity from May 1996 to March 1997 followed a normal seasonal progression, though conditions were anomalously cool and fresh. Starting in March 1997, positive anomalies in sea level and …

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Estimating The Mean Ocean-Bay Exchange Rate Of The Chesapeake Bay, Jay A. Austin Jan 2002

Estimating The Mean Ocean-Bay Exchange Rate Of The Chesapeake Bay, Jay A. Austin

CCPO Publications

A model of the salt balance in the Chesapeake Bay is discussed, which takes into account only time-dependent riverine input and mean ocean-bay exchange. Estimates of (spatial) mean bay salinity are made using two different data sources: a 16 year record of surveys taken by the Environmental Protection Agency's Chesapeake Bay Program, and a 10 year record of hydrographic sections taken in the lower bay by the Center for Coastal Physical Oceanography at Old Dominion University. Using United States Geological Survey river flow data to force the model, both data sets are consistent with this simple model and both imply …

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The Northeast Pacific Globec Program: Coastal Gulf Of Alaska, Thomas J. Weingartner, Kenneth Coyle, Bruce Finney, Russell Hopcroft, Terry Whitledge, Richard Brodeur, Michael Dagg, Edward Farley, Dale Haidvogel, Thomas Royer Jan 2002

The Northeast Pacific Globec Program: Coastal Gulf Of Alaska, Thomas J. Weingartner, Kenneth Coyle, Bruce Finney, Russell Hopcroft, Terry Whitledge, Richard Brodeur, Michael Dagg, Edward Farley, Dale Haidvogel, Thomas Royer

CCPO Publications

(First Paragraph) The Gulf of Alaska (GOA) continental shelf encompasses approximately 370,000 km2, or about 13% of the U.S. continental shell and supports a rich and diverse marine ecosystem including some of the largest commercial fisheries in the U.S. Exclusive Economic Zone. Of particular economic importance is the salmon fishery, which was worth on the order of $170 million (landed value) in 2000 accrued from a catch of over 100 million fish. However, there is considerable variability on both interannual and longer time scales in harvest and recruitment success to this and other GOA fisheries. Of recent interest …

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Sedimentation Rates And Metal Retention In An Urban Louisiana Swamp, Renee Lynn Sanders Jan 2002

Sedimentation Rates And Metal Retention In An Urban Louisiana Swamp, Renee Lynn Sanders

LSU Master's Theses

Naturally vegetated areas converted to urban uses increases impervious surfaces in a watershed with corresponding increases in nutrient, sediment, and metal loadings to downstream ecosystems. Wetlands mitigate detrimental impacts by transforming or retaining pollutants. Current and historic sedimentation and metal retention rates were measured in an urban, depressional wetland in Baton Rouge, Louisiana to evaluate landscape position and watershed development on these processes. Sedimentation disks, feldspar marker horizons, and Cs137 analyses were used in three distinct landscape positions. Inflow channels had the highest elevation and water velocity while the interior was located in the lowest elevations with the longest hydroperiod. …

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The Effects Of Fall Coldfront Passages On The Nekton Community In A Tidal Creek In Port Fourchon, La, As Monitored By Hydroacoustics, David J. Harmon Jan 2002

The Effects Of Fall Coldfront Passages On The Nekton Community In A Tidal Creek In Port Fourchon, La, As Monitored By Hydroacoustics, David J. Harmon

LSU Master's Theses

Split-beam hydroacoustic sampling with two, 420 KHz, 2x6 degree elliptical transducers was evaluated as a tool to quantify nekton movements in a Louisiana estuary. I measured the effects of atmospheric cold front passages on nekton in a tidal creek in Port Fourchon, LA during the fall of 2000. Six “fronts” were sampled between October 6 and December 18, 2000. Nekton density ranged from 0 to 24.4 fish/m3 with an overall mean of 2.44 fish/m3. Net samples were taken to supplement the acoustic data with species composition data. Species composition changed from October to December. A higher number …

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Wintertime Shoreward Near-Surface Currents South Of Cape Hatteras, Dana K. Savidge Jan 2002

Wintertime Shoreward Near-Surface Currents South Of Cape Hatteras, Dana K. Savidge

CCPO Publications

[1] Cross-isobath flow on continental shelves is of interest for a variety of reasons. Near Cape Hatteras, North Carolina, the transport of larval organisms, pollutants, and oceanic carbon budget constituents to and from the adjacent Albemarle and Pamlico Sounds may depend critically on cross-isobath currents. Shoreward currents in the near-surface waters south of Cape Hatteras are documented herein, on the basis of continuous 2-year time series, encompassing all or part of three consecutive winters. Energetic shoreward currents exist similar to30% of the time from midfall through late spring. These currents are evident over the 20 and 35 m isobaths along …

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Response Of Anchovy (Engaulis Ringens) Off Northern Chile To The 1997-1999 El Niño-La Niña Sequence, José L. Blanco, Patricio Barria, Jorge Castillo, Larry P. Atkinson Jan 2002

Response Of Anchovy (Engaulis Ringens) Off Northern Chile To The 1997-1999 El Niño-La Niña Sequence, José L. Blanco, Patricio Barria, Jorge Castillo, Larry P. Atkinson

CCPO Publications

No abstract provided.

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Algal Blooms Reduce The Uptake Of Toxic Methylmercury In Freshwater Food Webs, Paul C. Pickhardt, Carol L. Folt, Celia Y. Chen, Bjoern Klaue, Joel D. Blum Jan 2002

Algal Blooms Reduce The Uptake Of Toxic Methylmercury In Freshwater Food Webs, Paul C. Pickhardt, Carol L. Folt, Celia Y. Chen, Bjoern Klaue, Joel D. Blum

Dartmouth Scholarship

Mercury accumulation in fish is a global public health concern, because fish are the primary source of toxic methylmercury to humans. Fish from all lakes do not pose the same level of risk to consumers. One of the most intriguing patterns is that potentially dangerous mercury concentrations can be found in fish from clear, oligotrophic lakes whereas fish from greener, eutrophic lakes often carry less mercury. In this study, we experimentally tested the hypothesis that increasing algal biomass reduces mercury accumulation at higher trophic levels through the dilution of mercury in consumed algal cells. Under bloom dilution, as algal biomass …

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Hydrodynamics And Freshwater Diversion Within Barataria Basin, Dongho Park Jan 2002

Hydrodynamics And Freshwater Diversion Within Barataria Basin, Dongho Park

LSU Doctoral Dissertations

In order to understand the physical processes in the Barataria estuary, a previously developed two-dimensional, depth-integrated hydrodynamic model is applied to simulate estuarine processes. The equations for conservation of mass and momentum predict specific physical processes when forced by tidal and salinity variations at the open boundaries, wind forcing patterns, precipitation and evaporation over the model domain, and freshwater runoff as point sources. This study is focused on examining the impact of freshwater dispersion from the freshwater sources. Thus, a hydrologic model was developed to estimate runoff. Furthermore grid size was reduced, a new advective code added, and baroclinic effects …

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Scientific And Management Perspectives In Wetland Groundwater Hydrology, Lorna Veronica Inniss Jan 2002

Scientific And Management Perspectives In Wetland Groundwater Hydrology, Lorna Veronica Inniss

LSU Doctoral Dissertations

Wetland groundwater hydrology was investigated at different spatial scales to assess the usefulness of the information to coastal managers. Specific objectives were to: (1) review studies related to coastal groundwater discharge, evaluating techniques and identifying controls; (2) understand regional trends in groundwater flow along the U.S. East and Gulf coasts; (3) evaluate the applicability of naturally occurring radioisotopes as indicators of groundwater in a shallow deltaic system; and (4) evaluate groundwater-surface water exchange within Barataria Basin, Louisiana. Results of the review confirmed discharge estimates vary over several orders of magnitude, due to differences in precipitation and tidal prisms. In addition, …

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Distribution Of The Euryhaline Squid Lolliguncula Brevis In Chesapeake Bay: Effects Of Selected Abiotic Factors, I. K. Bartol, R. Mann, M. Vecchione Jan 2002

Distribution Of The Euryhaline Squid Lolliguncula Brevis In Chesapeake Bay: Effects Of Selected Abiotic Factors, I. K. Bartol, R. Mann, M. Vecchione

Biological Sciences Faculty Publications

The majority of cephalopods are thought to have limitations arising from physiology and locomotion that exclude them from shallow, highly variable, euryhaline environments. The brief squid Lolliguncula brevis may be a notable exception because it tolerates low salinities, withstands a wide range of environmental conditions, and swims readily in shallow water. Little is known about the distribution of L. brevis in Chesapeake Bay, a diverse and highly variable estuary. Therefore, a survey of L. brevis was conducted in the Virginia portion of Chesapeake Bay from 1993 to 1997 using a 9.1 m otter trawl, and the effects of selected factors …

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Evaluation Of Nile Tilapia Pond Management Strategies In Egypt, Bartholomew W. Green, Zenab El Nagdy, Hussein Hebicha Jan 2002

Evaluation Of Nile Tilapia Pond Management Strategies In Egypt, Bartholomew W. Green, Zenab El Nagdy, Hussein Hebicha

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

Five pond management strategies for Nile tilapia (Oreochromis niloticus L.) production were evaluated in 0.1-ha earthen ponds in Egypt during a 145-day production cycle. Pond management strategies developed by the Pond Dynamics/Aquaculture Collaborative Research Support Program (PD/A CRSP) were compared to a traditional and to a modified Egyptian pond management strategy. Young-of-year Nile (mixed-sex or sex-reversed) tilapia were stocked into ponds at 20,000 fish ha-1. Sex-reversed tilapia were stocked into chemical fertilization, organic fertilization plus formulated feed, and feed only treatment ponds, while mixed-sex tilapia were stocked into organic fertilization plus formulated feed, and chemical plus organic …

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A Procedural Evaluation Of An Analytic-Deliberative Process: The Columbia River Comprehensive Impact Assessment, Aimee Guglielmo Kinney, Thomas M. Leschine Jan 2002

A Procedural Evaluation Of An Analytic-Deliberative Process: The Columbia River Comprehensive Impact Assessment, Aimee Guglielmo Kinney, Thomas M. Leschine

United States Army Corps of Engineers, Omaha District

The U.S. Department of Energy's Columbia River Comprehensive Impact Assessment (CRCIA) was an ambitious attempt to direct its cleanup of the Hanford Nuclear Reservation toward the most significant risks to the Columbia River resulting from past plutonium production. DOE's approach was uncommonly open, including tribal, regulatory agency, and other Hanford interest group representatives on the board that was to develop the assessment approach. The CRCIA process had attributes of the ``analytic-deliberative'' process for risk assessment recommended by the National Research Council. Nevertheless, differences between the DOE and other participants over what was meant by the term ``comprehensive'' in the group's …

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Derivation Of A Tasselled Cap Transformation Based On Landsat 7 At-Satellite Reflectance, C. Huang, Wylie L. Yang, Collin Homer, G. Zylstra Jan 2002

Derivation Of A Tasselled Cap Transformation Based On Landsat 7 At-Satellite Reflectance, C. Huang, Wylie L. Yang, Collin Homer, G. Zylstra

United States Geological Survey: Staff Publications

A new tasselled cap transformation based on Landsat 7 at-satellite reflectance was developed. This transformation is most appropriate for regional applications where atmospheric correction is not feasible. The brightness, greenness and wetness of the derived transformation collectively explained over 97% of the spectral variance of the individual scenes used in this study.

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Strontium Isotopic Signatures Of The Streams And Lakes Of Taylor Valley, Southern Victoria Land, Antarctica: Chemical Weathering In A Polar Climate, W. B. Lyons, Carmen A. Nezat, Larry V. Benson, Thomas D. Bullen, Elizabeth Y. Graham, Jesicca Kidd, Kathleen A. Welch, James M. Thomas Jan 2002

Strontium Isotopic Signatures Of The Streams And Lakes Of Taylor Valley, Southern Victoria Land, Antarctica: Chemical Weathering In A Polar Climate, W. B. Lyons, Carmen A. Nezat, Larry V. Benson, Thomas D. Bullen, Elizabeth Y. Graham, Jesicca Kidd, Kathleen A. Welch, James M. Thomas

United States Geological Survey: Staff Publications

We have collected and analyzed a series of water samples from three closed-basin lakes (Lakes Bonney, Fryxell, and Hoare) in Taylor Valley, Antarctica, and the streams that flow into them. In all three lakes, the hypolimnetic waters have different 87Sr/86Sr ratios than the surface waters, with the deep water of Lakes Fryxell and Hoare being less radiogenic than the surface waters. The opposite occurs in Lake Bonney. The Lake Fryxell isotopic ratios are lower than modern-day ocean water and most of the whole-rock ratios of the surrounding geologic materials. A conceivable source of Sr to the system …

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Ontogeny And Intervals Of Development In Five Reef-Associated Species Of Blenny From The Northern Gulf Of Mexico (Teleostei: Blenniidae), James G. Ditty Jan 2002

Ontogeny And Intervals Of Development In Five Reef-Associated Species Of Blenny From The Northern Gulf Of Mexico (Teleostei: Blenniidae), James G. Ditty

LSU Doctoral Dissertations

I examined patterns and timing of ontogeny and relative growth in five species of blenny (Teleostei: Blenniidae) from the northern Gulf of Mexico by assigning a suite of discrete character state scores to ontogenetic events (10 external traits; 218 total specimens). This is the first study to evaluate developmental patterns in reef-associated fishes relative to the timing of metamorphosis and settlement by applying scaling techniques and statistical methods to quantify, differentiate, and select criteria for defining intervals of development across taxa. Blennies settle at a common state of ontogeny and share a common pattern of body and fin/cirrus growth. Three …

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A Method For The Perceptual Optimization Of Complex Visualizations, Donald H. House, Colin Ware Jan 2002

A Method For The Perceptual Optimization Of Complex Visualizations, Donald H. House, Colin Ware

Center for Coastal and Ocean Mapping

A common problem in visualization applications is the display of one surface overlying another. Unfortunately, it is extremely difficult to do this clearly and effectively. Stereoscopic viewing can help, but in order for us to be able to see both surfaces simultaneously, they must be textured, and the top surface must be made partially transparent. There is also abundant evidence that all textures are not equal in helping to reveal surface shape, but there are no general guidelines describing the best set of textures to be used in this way. What makes the problem difficult to perceptually optimize is that …

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Multibeam Volume Acoustic Backscatter Imagery And Reverberation Measurements In The Northeastern Gulf Of Mexico, Timoth C. Gallaudet, Christian De Moustier Jan 2002

Multibeam Volume Acoustic Backscatter Imagery And Reverberation Measurements In The Northeastern Gulf Of Mexico, Timoth C. Gallaudet, Christian De Moustier

Center for Coastal and Ocean Mapping

Multibeam volume acoustic backscatterimagery and reverberation measurements are derived from data collected in 200-m-deep waters in the northeastern Gulf of Mexico, with the Toroidal Volume Search Sonar (TVSS), a 68-kHz cylindrical sonar operated by the U.S. Navy’s Coastal System Station. The TVSS’s 360-degree vertical imaging plane allows simultaneous identification of multiple volume scattering sources and their discrimination from backscatter at the sea surface or the seafloor. This imaging capability is used to construct a three-dimensional representation of a pelagic fish school near the bottom. Scattering layers imaged in the mixed layer and upper thermocline are attributed to assemblages of epipelagic …

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Quantitative Ground-Truthing Of Habitat Characteristics Using Video Mosaic Images, Randy G. Cutter Jr., Yuri Rzhanov, Larry A. Mayer Jan 2002

Quantitative Ground-Truthing Of Habitat Characteristics Using Video Mosaic Images, Randy G. Cutter Jr., Yuri Rzhanov, Larry A. Mayer

Center for Coastal and Ocean Mapping

No abstract provided.

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A Conceptual Model Relating The Quasi-Biennial Oscillation And The Troposheric Biennial Oscillation, Kok Foo Kwan Jan 2002

A Conceptual Model Relating The Quasi-Biennial Oscillation And The Troposheric Biennial Oscillation, Kok Foo Kwan

Student Works (2000-2009)

A survey of the zonal wind throughout the troposphere and the lower stratosphere near the equator is made for the 41-year period of 1958-98. A similar survey of the 500- hPa geopotential height, sea surface temperature (SST) and tropopause height is also made, except that the survey period for the tropopause height is shorter than 41 years due to unavailability of data. Other than the well-known Quasi-Biennial Oscillation (QBO) feature in the lower stratosphere and the Tropospheric Biennial Oscillation (TBO) feature exhibited by the SST, similar oscillation features are found throughout the whole troposphere by both surveys. Autocorrelation functions, Pearson …

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Intra-Annual Variation In The Stable Oxygen And Carbon And Trace Element Composition Of Sclerosponges, P. K. Swart, S. Thorrold, B. Rosenheim, A. Eisenhauer, C. G. A. Harriason, M. Grammer, C. Latkoczy Jan 2002

Intra-Annual Variation In The Stable Oxygen And Carbon And Trace Element Composition Of Sclerosponges, P. K. Swart, S. Thorrold, B. Rosenheim, A. Eisenhauer, C. G. A. Harriason, M. Grammer, C. Latkoczy

Biological Sciences Faculty Publications

This paper presents data to support the presence of (1) intra-annual signals in the chemical composition (δ18O and Sr/Ca) of the skeletons ofsclerosponges from the Bahamas and (2) variable rates of skeletal accretion. These conclusions are based on data obtained by using a microsampling method for the stable oxygen and carbon isotopes in which material was extracted at a resolution of one sample every 34 μm and a laser microprobe which obtained trace element data every 20 μm (Sr, Mg, and Pb). An age model was established using a combination of changes in the concentration of Pb, the …

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Observations And Modelling Of The Near Equatorial Tropical Atmospheric Boundary Layer, Aiman Abdalla Soleiman Jan 2002

Observations And Modelling Of The Near Equatorial Tropical Atmospheric Boundary Layer, Aiman Abdalla Soleiman

Student Works (2000-2009)

Existing models developed to simulate the evolution of the atmospheric boundary layer (ABL) have focused on the conditions prevalent in mid-latitude regions. The problem for these models in terms of their application to tropical conditions is that the mid-latitude ABL is, in many respects, physically quite different from that of the tropical ABL. Because of this, and due also to the relative lack of relevant atmospheric observations in tropical areas, the tropical ABL is incorrectly represented in such models, and also in various applications that use the mid-latitude ABL representation (for example, air pollution dispersion models). A recent review of …

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Feeding Habits Of Blacktip Sharks, Carcharhinus Limbatus, And Atlantic Sharpnose Sharks, Rhizoprionodon Terraenovae, In Louisiana Coastal Waters, Kevin Patrick Barry Jan 2002

Feeding Habits Of Blacktip Sharks, Carcharhinus Limbatus, And Atlantic Sharpnose Sharks, Rhizoprionodon Terraenovae, In Louisiana Coastal Waters, Kevin Patrick Barry

LSU Master's Theses

Little is known regarding the feeding behavior of many shark species. Even less is known about shark feeding habits in Louisiana coastal waters. The stomach contents of gillnet-captured blacktip sharks (n=356), Carcharhinus limbatus, and Atlantic sharpnose sharks (n=55), Rhizoprionodon terraenovae, were examined in this study. Roughly half of the blacktip stomachs (52%) and sharpnose stomachs (45%) contained prey items. The primary prey item in terms of percent number, occurrence, and weight for blacktips and sharpnose was the gulf menhaden, Brevoortia patronus. Both blacktips and sharpnose appear to mainly be piscivores; however, no members of Sciaenidae, the most common family of …

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The Importance Of Zooplankton In The Diets Of Blue Runner (Caranx Crysos) Near Offshore Petroleum Platforms In The Northern Gulf Of Mexico, Sean Francis Keenan Jan 2002

The Importance Of Zooplankton In The Diets Of Blue Runner (Caranx Crysos) Near Offshore Petroleum Platforms In The Northern Gulf Of Mexico, Sean Francis Keenan

LSU Master's Theses

Blue runner (Caranx crysos), common around offshore petroleum platforms in the Gulf of Mexico, were found to forage extensively on meso- and macro-zooplankton during the summer months. Larval decapods and stomatopods, hyperiid amphipods, pteropods, and larval and juvenile fishes were common components of their diet. Feeding periodicity results suggest that blue runner around platforms were capable of feeding throughout the night at the same intensity as the day. Size selectivity indicated that larger prey, such as fish were consumed during the night and smaller decapod crustaceans were consumed during the day. Blue runner collected from open waters away from platforms …

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Denitrification Potential Of Sediment From A Future Mississippi River Diversion Site In Louisiana, Roy Ryuta Iwai Jan 2002

Denitrification Potential Of Sediment From A Future Mississippi River Diversion Site In Louisiana, Roy Ryuta Iwai

LSU Master's Theses

Denitrification potential was determined in surface sediment from Lake Cataouatche, the receiving basin for a future Mississippi River diversion located in the northern portion of the Barataria Basin estuary. Nitrate removal and denitrification was measured in the laboratory using static sediment microcosms flooded with lake water. Dissolved potassium nitrate (KNO3) was added to the microcosms to achieve: 1) an initial nitrate concentration similar to the mean Mississippi River concentration (~1.4 mg NO3-N l-1), and, 2) a high initial nitrate concentration to elicit a denitrification potential (~50 mg NO3-N l-1). Denitrification …

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