Water quality assessment and characterisation of chlorophyll-a variability related to river discharges, within the southeastern Bay of Biscay : evaluation and development of chlorophyll-a algorithms for MODIS and MERIS imagery

222 p. : il.

An oceanographic atlas of the Eastern Tropical Pacific Ocean, based on data from EASTROPIC Expedition, October-December 1955.

ENGLISH: EASTROPIC Expedition was a cooperative oceanographic study of the eastern tropical Pacific Ocean conducted during the period 2 October through 16 December 1955. The five participating agencies and the ships they operated were: Scripps Institution of Oceanography (SIO), Spencer F. Baird and Horizon; Pacific Oceanic Fisheries Investigations (POFI) of the U. S. Fish and Wildlife Service, now Honolulu Biological Laboratory (HBL) of the U. S. Bureau of Commercial Fisheries, Hugh M. Smith; California Department of Fish and Game, N. B. Scofield; the Peruvian Navy, Bondu; and the Inter-American Tropical Tuna Commission which operated no vessels but supplied equipment and personnel. In addition to these planned participations in EASTROPIC Expedition, valuable information was provided by CCOFI Cruise 5512 of the California Cooperative Oceanic Fisheries Investigations, conducted during the period 29 November -16 December 1955 with the two vessels Stranger and Black Douglas. While the observational programs of most of the agencies involved, in part, special hydrographic-biological studies of known features and processes in the region (see reports listed under Data Sources) the deployment of ships and therefore of observations was sufficient that EASTROPIC Expedition could be considered a survey of the eastern tropical Pacific. This report is concerned with that aspect of the Expedition and is a presentation in atlas form of most of the hydrographic data collected. For reasons given below, emphasis has been placed on the upper 300 m of the water column. SPANISH: La Expedición EASTROPIC es un estudio oceanográfico cooperativo del Océano Pacífico Oriental Tropical llevado a cabo durante el período del 2 de octubre al 16 de dícíembre de 1955. Las cinco agencias participantes y los barcos operados por ellas son los siguientes: Scrípps Instítutíon of Oceanography (SIO) , Spencer F. Baird y Horizon; Pacific Oceanic Fisheries Investigatíons (PO'FI) del U. S. Fish and Wildlife Service, ahora Honolulu Biological Laboratory (BHL) del U. S. Bureau of Commercial Fisheries, Hugh M. Smith; California Department of Fish and Game, N. B. Scofield; la Marina Peruana, Bondu; y la Comisión Interamericana del Atún Tropical que no dirigió ningún barco pero proporcionó equipo y personal. Además de estas participaciones planeadas en la Expedición EASTROPIC, fué suministrada información de valor por el Crucero CCOFI 5512 del California Cooperative Fisheries Investigatíons, llevado a cabo durante el período del 29 de noviembre al 16 de diciembre de 1955 con los barcos Stranger y Black Douglas. Aunque los programas de observación de la mayoría de las agencias, comprendieron en parte estudios especiales hidrográficos y biológicos de las características y de los procesos conocidos de la región (véase los informes indicados bajo Fuente de Datos), el despliegue de los barcos, y por lo tanto, de las observaciones, fué suficiente para que la Expedición EASTROPIC pudiera ser considerada como una encuesta del Pacífico Oriental Tropical. Este informe se refiere a este aspecto de la Expedición y es una presentación, en forma de un atlas, de la mayoría de los datos hidrográficos recolectados. Por las razones que se dan a continuación, se le dió énfasis a los 300 m., superiores de la columna de agua. (PDF contains 136 pages.)

Oceanographic Profiling and Spectroradiometer Observations from the MOCE-1 Cruise: 28 August to 8 October 1992

This report contains the frrst observations made for the Modis Optical Characterization Experiment (MOCE). Data presented here were obtained on the R/V DeSteiguer between 28 August and 8 October along the central California coast and in Monterey Bay. Three types of data are reported here: high spectral resolution radiometry at three depths for seven stations; salinity, temperature, fluorescence and beam attenuation profiles at the same stations; and total suspended matter and suspended organic carbon and nitrogen. [PDF contans 164 pages]

Panama City Fisheries Resources Office: FY 2007 Annual Report

HIGHLIGHTS FOR FY 2007 1. Completed a three-year Gulf sturgeon population study on the Escambia River, Florida. The population was estimated at 451 fish. 2. Implemented the Gulf Striped Bass Restoration Plan by coordinating the 24th Annual Morone Workshop, leading the technical committee, transporting broodfish, coordinating stocking on the Apalachicola-Chattahoochee-Flint (ACF) river system, and evaluating post-stocking success. 3. Completed a survey to document the extent of aquatic resources, recreational fishing opportunities, and fishery management needs on Department of Defense (DoD) facilities located in Region 4. 4. Continued a project in the Apalachicola River to describe the effects of exceptional drought conditions on freshwater mussel recovery. 5. Initiated a study to locate extant populations of the federally endangered Ochlockonee moccasinshell in the Ochlockonee River Basin. We documented the first live individuals in 14 years. 6. Completed a five-year status review for seven threatened and endangered freshwater mussels in the NEG drainages. 7. Restored Mill Creek to improve habitat for the endangered Okaloosa darter by removing six fish passage barriers and creating approximately 3,000 linear feet of new and regenerated stream channel with floodplain and native vegetation. 8. Completed a fish passage project that connected about 5 miles of habitat in Little Rocky Creek, Eglin Air Force Base, to benefit the Okaloosa darter. 9. Completed a threats analysis to aquatic species in the Chipola River watershed using GIS stream data, aerial imagery, and land cover data. 10. Multiple outreach projects were completed to detail aquatic resource conservation needs and opportunities, including National Fishing Week, Earth Day, several festivals, and school outreach.

Panama City Fisheries Resources Office: FY 2006 Annual Report

HIGHLIGHTS FOR FY 2006 1. Captured and tagged 475 Gulf sturgeons in five Florida rivers and one bay. 2. Documented Gulf sturgeon marine movement and habitat use in the Gulf of Mexico. 3. Assisted the National Oceanic and Atmospheric Administration (NOAA) with the collection of Gulf sturgeon, implantation of acoustic tags, and monitoring of fish in a study to examine movement patterns and habitat use in Pensacola and Choctawhatchee bays post-Hurricane Ivan. 4. Provided technical assistance to Jon “Bo” Sawyer in completing a study – Summer Resting Areas of the Gulf Sturgeon in the Conecuh/Escambia River System, Alabama-Florida – for acquiring a Degree of Master of Science at Troy University, Alabama. 5. Coordinated tagging and data collection with NOAA observers aboard trawlers while collecting Gulf sturgeon during dredging operations in the coastal Gulf of Mexico. 6. Hosted the 7th Annual Gulf Sturgeon Workshop. 7. Implemented Gulf Striped Bass Restoration Plan by coordinating the 23rd Annual Morone Workshop, leading the technical committee, transporting broodfish, coordinating the stocking on the Apalachicola-Chattahoochee-Flint (ACF) river system, and evaluating post-stocking success. 8. Continued updating and managing the Freshwater Mussel Survey Database, a Geographic Information System (GIS) database, for over 800 unique sites in the Northeast Gulf (NEG) drainages in Alabama (AL), Georgia (GA), and Florida (FL). 9. Formed a recovery implementation team for listed mussels in the ACF river basin and oversaw grant cooperative agreements for 14 listed and candidate freshwater mussels in the NEG watersheds. 10. Initiated a project in the Apalachicola River to relocate mussels stranded as a result of drought conditions, and calculate river flows at which mussels would be exposed. 11. Initiated a project in Sawhatchee Creek, Georgia to determine the status of threatened and endangered (T&E) freshwater mussels and target restoration projects, population assessments, and potential population augmentation to lead toward recovery of the listed species. 12. Initiated a study to determine the age and growth of the endangered fat threeridge mussel (Amblema neislerii). 13. Provided technical assistance to the Panama City Ecological Services office for a biological opinion on the operations of Jim Woodruff Lock and Dam and its effects on the listed species and designated and proposed critical habitat in the Apalachicola River, Florida. 14. Assisted with a multi-State, inter-agency team to develop a management plan to restore the Alabama shad in the ACF river system. 15. Conducted fishery surveys on Tyndall AFB, Florida and Ft. Benning, Georgia and completed a report with recommendations for future recreational fishery needs. 16. Provided fishery technical assistance to four National Wildlife Refuges (NWR) (i.e., Okefenokee NWR, Banks Lake NWR, St. Vincent NWR, and St. Marks NWR). 17. Initiated an Aquatic Resources and Recreation Fishing Survey on Department of Defense facilities located in Region 4. 18. Identified 130 road-stream crossings on Eglin AFB for rehabilitation and elimination of sediment imputs. 19. Continued the Aquatics Monitoring Program at Eglin AFB to assess techniques that determine current status and sustainability of aquatic habitat and develop a measure to determine quality or degradation of habitat. 20. Assisted Eglin AFB Natural Resource managers in revising the installation’s Integrated Natural Resources Management Plan (INRMP) and its associated component plans. 21. Coordinated recovery efforts for the endangered Okaloosa darter including population/life history surveys, stream restoration, and outreach activities. 22. Initiated a comprehensive status review of the Okaloosa darter with analyses performed to assess available habitat, preferred habitats, range expansions/reductions/fragmentations, population size, and probability of extinction. 23. Assisted the Gulf Coastal Plain Ecosystem Partnership and the Florida Fish and Wildlife Conservation Commission (FWC) under a Memorandum of Agreement to develop conservation strategies, implement monitoring and assessment programs, and secure funds for aquatic management programs in six watersheds in northwest Florida and southeast Alabama. 24. Entered into a cooperative agreement with the U.S. Air Force to encourage the conservation and rehabilitation of natural resources at Hurlburt Field, Florida. 25. Multiple outreach projects were completed to detail aquatic resources’ conservation needs and opportunities; including National Fishing Week, Earth Day, several festivals, and school outreach.

Panama City Fisheries Resources Office: FY 2005 Annual Report

HIGHLIGHTS FOR FY 2005 1. Assisted with a study to assess hurricane impacts to Gulf sturgeon critical foraging habitat. 2. Documented Gulf sturgeon marine movement and habitat use in the Gulf of Mexico. 3. Documented Gulf sturgeon spawning with the collection of fertilized eggs in the Apalachicola River, Florida. 4. Documented Gulf sturgeon spawning with the collection of fertilized eggs in the Yellow River, Florida. 5. Assisted with benthic invertebrate survey at Gulf sturgeon marine foraging grounds. 6. Implemented Gulf Striped Bass Restoration Plan by coordinating the 22nd Annual Morone Workshop, leading the technical committee, transporting broodfish, and coordinating the stocking on the Apalachicola-Chattahoochee-Flint (ACF) river system. 7. Over 87,000 Phase II Gulf striped bass were marked with sequential coded wire tags and stocked in the Apalachicola River. Post-stocking evaluations were conducted at 45 sites in the fall and spring and 8 thermal refuges in the summer. 8. Completed fishery surveys on 4 ponds on Eglin AFB totaling 53 acres, and completed a report with recommendations for future recreational fishery needs. 9. Completed final report for aquatic monitoring at Eglin AFB from 1999 to 2004. 10. Completed a field collection of the endangered Okaloosa darter to be incorporated into a status review to be completed in FY06. 11. Provided technical assistance to the Region 4 National Wildlife Refuge (NWR) program on changes to the fishery conservation targets for the region. Also provided technical assistance to four NWRs (i.e., Okefenokee NWR, Banks Lake NWR, St. Vincent NWR, and St. Marks NWR) relative to hurricanes and recreational fishing. 12. A draft mussel sampling protocol was tested in wadeable streams in Northwest Florida and southwest Georgia, and an associated field guide, poster, and Freshwater Mussel Survey Protocol and Identification workshop were completed in FY05. 13. Implemented recovery plan and candidate conservation actions for 14 listed and candidate freshwater mussels in the Northeast Gulf Watersheds. 14. Initiated or completed multiple stream restoration and watershed management projects. A total of 7.5 stream miles were restored for stream fishes, and 11 miles of coastline were enhanced for sea turtle lighting. A total of 630 acres of wetlands and 2,401 acres of understory habitat were restored. 15. Conducted a watershed assessment to develop a threats analysis for prioritizing restoration, protection, and enhancement to natural resources of Spring Creek, Georgia and Canoe Creek, Florida. 16. Continued the formation of an Unpaved Road Interagency Team of Federal, State, and local agencies in Northwest Florida to promote stream protection and restoration from unpaved road sediment runoff. Began the development of a technical committee agreement. 17. Conducted Alabama Unpaved Road Inventory within the Northeast Gulf Ecosystem. Data collection will be completed during FY06. 18. Finalized the development of two North Florida hydrophysiographic regional curves for use by the Florida Department of Transportation (DOT) and others involved with stream restoration and protection. Initiated the development of the Alabama Coastal Plain Riparian Reference Reach and Regional Curves for use by the Alabama Department of Environmental Management (ADEM). 19. Provided technical assistance in collecting data, analysis, and thesis formulation with Troy University, Alabama, to identify the influence of large woody debris in southeastern coastal plain streams. 20. Completed pre- and post-restoration fish community monitoring at several restoration projects including Big Escambia Creek, Magnolia Creek, and Oyster Lake, Florida. 21. Established a watershed partnership for the Chipola River in Alabama and Florida and expanded development and participation in the Spring Creek Watershed Partnership, Georgia. 22. Continued to identify barriers which inhibit the movement of aquatic species within the Northeast Gulf Ecoregion. 23. Completed a report on road crossing structures in Okaloosa darter streams to guide the closure/repair/maintenance of roads to contribute to recovery of the endangered species. In cooperation with Three Rivers RC&D Council, fish passage sites identified in the report were prioritized for restoration. 24. Monitored Aquatic Nuisance Species in the Apalachicola River and tested the sterility of exotic grass carp. 25. Multiple outreach projects were completed to detail aquatic resources conservation needs and opportunities. Participated in National Fishing Week event, several festivals, and school outreach.

Panama City Fisheries Resources Office: FY 2003 Annual Report

HIGHLIGHTS FOR FY 2003 1. Continued a 3-year threatened Gulf sturgeon population estimate in the Escambia River, Florida and conducted presence-absence surveys in 4 other Florida river systems and 1 bay. 2. Five juvenile Gulf sturgeon collected, near the mouth of the Choctawhatchee River, Florida, were equipped with sonic tags and monitored while over-wintering in Choctawhatchee Bay. 3. Continued to examine Gulf sturgeon marine habitat use. 4. Implemented Gulf Striped Bass Restoration Plan by coordinating the 20th Annual Morone Workshop, leading the technical committee, transporting broodfish, and coordinating the stocking on the Apalachicola-Chattahoochee-Flint (ACF) river system. 5. Over 73,000 Phase II Gulf striped bass were marked with sequential coded wire tags and stocked in the Apalachicola River. Post-stocking evaluations were conducted at 31 sites. 6. Three stream fisheries assessment s were completed to evaluate the fish community at sites slated for habitat restoration by the Partners for Fish and Wildlife Program (PFW). 7. PFW program identified restoration needs and opportunities for 10 areas. 8. Developed an Unpaved Road Evaluation Handbook. 9. Completed restoration of Chipola River Greenway, Seibenhener Streambank Restoration, Blackwater River State Forest, and Anderson Property. 10. Assessments for fluvial geomorphic conditions for design criteria were completed for 3 projects. 11. Geomorphology in Florida streams initiated development of Rosgen regional curves for Northwest Florida for use by the Florida Department of Transportation. 12. Developed a Memorandum of Understanding between partners for enhancing, protecting, and restoring stream, wetland, and upland habitat in northwest Florida 13. Completed aquatic fauna and fish surveys with new emphasis on integration of data from reach level into watershed and landscape scale and keeping database current. 14. Compliance based sampling of impaired waterbodies on Eglin Air Force Base in conjunction with Florida Department of Environmental Protection for Total Maximum Daily Load development support. 15. Surveyed 20 sites for the federally endangered Okaloosa darter, provided habitat descriptions, worked with partners to implement key recovery tasks and set priorities for restoration. 16. Worked with partners to develop a freshwater mussel survey protocol to provide standard operating procedures for establishing the presence/absence of federally listed mussel species within a Federal project area. 17. GIS database was created to identify all known freshwater mussel records from the northeast Gulf ecosystem. 18. Completed recovery plan for seven freshwater mussels and drafted candidate elevation package for seven additional mussels. Developed proposals to implement recovery plan. 19. Worked with Corps of Engineers and State partners to develop improved reservoir operating policies to benefit both riverine and reservoir fisheries for the ACF river system. 20. Multiple outreach projects were completed to detail aquatic resources conservation opportunities. 21. Multiple stream restoration and watershed management projects initiated or completed (see Appendix A).

Panama City Fisheries Resources Office: FY 2002 Annual Report

HIGHLIGHTS FOR FY 2002 1. United States Senator Bob Graham assisted with a Gulf sturgeon survey. 2. Completed 3-year Gulf sturgeon population study in the Choctawhatchee River drainage. 3. Completed Gulf sturgeon potential spawning habitat survey for Northwest Florida and Southeast Alabama river systems. 4. Initiated Gulf sturgeon marine habitat and food resources study. 5. Completed Gulf sturgeon sentinel fish study. 6. Coordinated and conducted tagging of over 110,000 Phase II striped bass at Welaka and Warm Springs National Fish Hatchery. 7. Completed Okefenokee National Wildlife Refuge fishery sampling. 8. Developed a manuscript regarding the fishery of Banks Lake NWR. 9. Initiated development of a fish Index of Biotic Integrity for Florida panhandle streams. 10. Coordinated Okaloosa darter workshop. 11. Continued examining insect communities on Eglin AFB. 12. Sponsored and coordinated stream restoration workshop. 13. Provided technical assistance via Partners for Fish and Wildlife for stream restoration within the Northeast Gulf Ecosystem. 14. Finalized regional curve development in the Northern Region of Florida and secured significant funds for FY03 to expand to other regions in Florida. 15. Initiated freshwater mussel conservation in the Northeastern Gulf Ecosystem.

Origin of Th/U variations in chondritic meteorites

Isotope dilution thorium and uranium analyses of the Harleton chondrite show a larger scatter than previously observed in equilibrated ordinary chondrites (EOC). The linear correlation of Th/U with 1/U in Harleton (and all EOC data) is produced by variation in the chlorapatite to merrillite mixing ratio. Apatite variations control the U concentrations. Phosphorus variations are compensated by inverse variations in U to preserve the Th/U vs. 1/U correlation. Because the Th/U variations reflect phosphate ampling, a weighted Th/U average should converge to an improved solar system Th/U. We obtain Th/U=3.53 (1_-mean=0.10), significantly lower and more precise than previous estimates.

To test whether apatite also produces Th/U variation in CI and CM chondrites, we performed P analyses on the solutions from leaching experiments of Orgueil and Murchison meteorites.

A linear Th/U vs. 1/U correlation in CI can be explained by redistribution of hexavalent U by aqueous fluids into carbonates and sulfates.

Unlike CI and EOC, whole rock Th/U variations in CMs are mostly due to Th variations. A Th/U vs. 1/U linear correlation suggested by previous data for CMs is not real. We distinguish 4 components responsible for the whole rock Th/U variations: (1) P and actinide-depleted matrix containing small amounts of U-rich carbonate/sulfate phases (similar to CIs); (2) CAIs and (3) chondrules are major reservoirs for actinides, (4) an easily leachable phase of high Th/U. likely carbonate produced by CAI alteration. Phosphates play a minor role as actinide and P carrier phases in CM chondrites.

Using our Th/U and minimum galactic ages from halo globular clusters, we calculate relative supernovae production rates for ²³²Th/²³⁸U and ²³⁵U/²³⁸U for different models of r-process nucleosynthesis. For uniform galactic production, the beginning of the r-process nucleosynthesis must be less than 13 Gyr. Exponentially decreasing production is also consistent with a 13 Gyr age, but very slow decay times are required (less than 35 Gyr), approaching the uniform production. The 15 Gyr Galaxy requires either a fast initial production growth (infall time constant less than 0.5 Gyr) followed by very low decrease (decay time constant greater than 100 Gyr), or the fastest possible decrease (≈8 Gyr) preceded by slow in fall (≈7.5 Gyr).

Long Run Demand for Energy Services: the Role of Economic and Technological Development

36 p.

The energy spectra of uranium atoms sputtered from uranium metal and uranium dioxide targets

The energy spectra of ²³⁵U atoms sputtered from a 93% enriched ²³⁵U metal foil and a hot pressed ²³⁵U0₂ pellet by an 80 keV ⁴⁰Ar⁺ beam have been measured in the range 1 eV to 1 keV. The measurements were made using a mechanical time-of-flight spectrometer in conjunction with the fission track technique for detecting ²³⁵U. The design and construction of this spectrometer are discussed in detail, and its operation is mathematically analyzed.

The results of the experiment are discussed in the context of the random collision cascade model of sputtering. The spectrum obtained by the sputtering of the ²³⁵U metal target was found to be well described by the functional form E(E+E_b)^-2.77, where E_b = 5.4 eV. The ²³⁵U0₂ target produced a spectrum that peaked at a lower energy (~ 2 eV) and decreased somewhat more rapidly for E ≳ 100 eV.

The blackback flounder and its fishery in New England and New York

A decline in the abundance of blackback flounders, together with the withdrawal of vessels from this fishery, has resulted in a lowered catch in recent years compared to the peak period 1928 through 1931. Data obtained from U. S. Fish and Wildlife Service Hatchery catch records and from fishermen's log book records show a drop in abundance of 63 per cent from the early 1930's to the present in the Boothbay Harbor region and of 31 to 40 per cent in the area south of Cape Cod. Information on the early life history and distribution of young blackback flounders and the size and age composition and distribution of fish subject to the commercial and sport fisheries indicates that the young are the product of local spawning and that the sport and commercial fisheries draw on a resident stock of primarily adult fish.

Spectroscopic investigations of inter- and intramolecular processes in crystalline benzene

I. Introductory Remarks

A brief discussion of the overall organization of the thesis is presented along with a discussion of the relationship between this thesis and previous work on the spectroscopic properties of benzene.

II. Radiationless Transitions and Line broadening

Radiationless rates have been calculated for the ³B_1u→¹A_1g transitions of benzene and perdeuterobenzene as well as for the ¹B_2u→¹A_1g transition of benzene. The rates were calculated using a model that considers the radiationless transition as a tunneling process between two multi-demensional potential surfaces and assuming both harmonic and anharmonic vibrational potentials. Whenever possible experimental parameters were used in the calculation. To this end we have obtained experimental values for the anharmonicities of the carbon-carbon and carbon-hydrogen vibrations and the size of the lowest triplet state of benzene. The use of the breakdown of the Born-Oppenheimer approximation in describing radiationless transitions is critically examined and it is concluded that Herzberg-Teller vibronic coupling is 100 times more efficient at inducing radiationless transitions.

The results of the radiationless transition rate calculation are used to calculate line broadening in several of the excited electronic states of benzene. The calculated line broadening in all cases is in qualitative agreement with experimental line widths.

III. ³B_1u←¹A_1g Absorption Spectra

The ³B_1u←¹A_1g absorption spectra of C₆H₆ and C₆D₆ at 4.2˚K have been obtained at high resolution using the phosphorescence photoexcitation method. The spectrum exhibits very clear evidence of a pseudo-Jahn-Teller distortion of the normally hexagonal benzene molecule upon excitation to the triplet state. Factor group splitting of the 0 – 0 and 0 – 0 + v exciton bands have also been observed. The position of the mean of the 0 – 0 exciton band of C₆H₆ when compared to the phosphorescence origin of a C₆H₆ guest in a C₆D₆ host crystal indicates that the “static” intermolecular interactions between guest and hose are different for C₆H₆ and C₆D₆. Further investigation of this difference using the currently accepted theory of isotopic mixed crystals indicates that there is a 2cm^-1 shift of the ideal mixed crystal level per hot deuterium atom. This shift is observed for both the singlet and triplet states of benzene.

IV. ³E_1u←¹A_1g, Absorption Spectra

The ³E_1u←¹A_1g absorption spectra of C₆H₆ and C₆D₆ at 4.2˚K have been obtained using the phosphorescence photoexcitation technique. In both cases the spectrum is broad and structureless as would be expected from the line broadening calculations.

Proton magnetic resonance studies of ribonucleic acid complexes. I. Complexes of biological bases and oligonucleotides with RNA. II. Template recognition and the degeneracy of the genetic code

Part I. Complexes of Biological Bases and Oligonucleotides with RNA

The physical nature of complexes of several biological bases and oligonucleotides with single-stranded ribonucleic acids have been studied by high resolution proton magnetic resonance spectroscopy. The importance of various forces in the stabilization of these complexes is also discussed.

Previous work has shown that purine forms an intercalated complex with single-stranded nucleic acids. This complex formation led to severe and stereospecific broadening of the purine resonances. From the field dependence of the linewidths, T₁ measurements of the purine protons and nuclear Overhauser enhancement experiments, the mechanism for the line broadening was ascertained to be dipole-dipole interactions between the purine protons and the ribose protons of the nucleic acid.

The interactions of ethidium bromide (EB) with several RNA residues have been studied. EB forms vertically stacked aggregates with itself as well as with uridine, 3'-uridine monophosphate and 5'-uridine monophosphate and forms an intercalated complex with uridylyl (3' → 5') uridine and polyuridylic acid (poly U). The geometry of EB in the intercalated complex has also been determined.

The effect of chain length of oligo-A-nucleotides on their mode of interaction with poly U in D₂0 at neutral pD have also been studied. Below room temperatures, ApA and ApApA form a rigid triple-stranded complex involving a stoichiometry of one adenine to two uracil bases, presumably via specific adenine-uracil base pairing and cooperative base stacking of the adenine bases. While no evidence was obtained for the interaction of ApA with poly U above room temperature, ApApA exhibited complex formation of a 1:1 nature with poly U by forming Watson-Crick base pairs. The thermodynamics of these systems are discussed.

Part II. Template Recognition and the Degeneracy of the Genetic Code

The interaction of ApApG and poly U was studied as a model system for the codon-anticodon interaction of tRNA and mRNA in vivo. ApApG was shown to interact with poly U below ~20°C. The interaction was of a 1:1 nature which exhibited the Hoogsteen bonding scheme. The three bases of ApApG are in an anti conformation and the guanosine base appears to be in the lactim tautomeric form in the complex.

Due to the inadequacies of previous models for the degeneracy of the genetic code in explaining the observed interactions of ApApG with poly U, the "tautomeric doublet" model is proposed as a possible explanation of the degenerate interactions of tRNA with mRNA during protein synthesis in vivo.