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• 2241. [Article] The ecology and management of invasive plant species on tropical islands

  Graduation date:

  Citation × Citation Citation Abstract Copy Title: The ecology and management of invasive plant species on tropical islands Author: Hooper, Carolina Graduation date: Title: The ecology and management of invasive plant species on tropical islands Author: Hooper, Carolina Graduation date: Close

• 2242. [Article] Tuberculosis in Pacific salmon and steelhead trout

  Tuberculosis in salmonoid fishes was first observed in the 1952 run of fall chinook salmon (Oncorhynchus tshawytscha) returning to the Bonneville Hatchery of the Oregon Fish Commission. In the studies ...

  Citation × Citation Citation Abstract Copy Title: Tuberculosis in Pacific salmon and steelhead trout Author: Ordal, Erling Josef, 1906-, Oregon. Fish Commission, Wood, James W. Tuberculosis in salmonoid fishes was first observed in the 1952 run of fall chinook salmon (Oncorhynchus tshawytscha) returning to the Bonneville Hatchery of the Oregon Fish Commission. In the studies reported here, tuberculosis was found not only in adult spring chinook but in silver salmon (0. kisutch), blueback salmon (0. nerka), and in anadromous and resident strains of rainbow trout (Salmo gairdnerii). Advanced tuberculosis was found in salmonoid fishes held in fresh water for two years or longer, as well as in adults returning from the sea. Lesions were most frequently observed in the liver, and varied in size from small miliary tubercles to huge necrotic areas, filled with characteristic acid-fast bacilli. The typical bacilli were found in stained smears from the kidney, heart, musculature, brain, intestines, pyloric caeca, and roe of infected fish. The disease was originally observed in sexually-underdeveloped fish, and there is indication that it interferes with sexual maturation. It was found that tuberculosis in marked salmon known to be of hatchery origin was extremely high - in some cases 100 percent. Tuberculosis was absent in the small number of silver and chum salmon examined which were known to be the progeny from natural spawning. It is suggested that dissemination of the disease may be due to fish-cultural practices such as the feeding of untreated carcasses and the viscera from tuberculous fish. Since acid-fast bacilli were found in the roe of some fish, it is also suggested that the disease may be transmitted to healthy eggs during the process of fertilization. Tuberculous adult spring chinook were found less capable of surviving to maturity after they reached the spawning grounds than were non-infected fish. It is likely that tuberculosis also influences the ability of salmon to survive during earlier stages of their life history. The incidence of tuberculosis in adult spring chinook entering the Dexter holding ponds on the Middle Fork of the Willamette River in 1955 and 1956 was 8.7 and 6.1 percent, respectively. The increase in incidence to 58.8 percent in 1957 is attributed to the increased dependency of the run on artificial propagation necessitated by the construction of Lookout Point Dam. Among chinook caught in the Columbia River gill-net fishery in. February and in May 1956, 12.3 and 10.5 percent, respectively, of those examined were tuberculous. Although these are spring chinook, it is believed that hatchery reared fall chinook also entered the catch, especially during May, and may have contributed to the number of tuberculous fish taken. Title: Tuberculosis in Pacific salmon and steelhead trout Author: Ordal, Erling Josef, 1906-, Oregon. Fish Commission, Wood, James W. Tuberculosis in salmonoid fishes was first observed in the 1952 run of fall chinook salmon (Oncorhynchus tshawytscha) returning to the Bonneville Hatchery of the Oregon Fish Commission. In the studies reported here, tuberculosis was found not only in adult spring chinook but in silver salmon (0. kisutch), blueback salmon (0. nerka), and in anadromous and resident strains of rainbow trout (Salmo gairdnerii). Advanced tuberculosis was found in salmonoid fishes held in fresh water for two years or longer, as well as in adults returning from the sea. Lesions were most frequently observed in the liver, and varied in size from small miliary tubercles to huge necrotic areas, filled with characteristic acid-fast bacilli. The typical bacilli were found in stained smears from the kidney, heart, musculature, brain, intestines, pyloric caeca, and roe of infected fish. The disease was originally observed in sexually-underdeveloped fish, and there is indication that it interferes with sexual maturation. It was found that tuberculosis in marked salmon known to be of hatchery origin was extremely high - in some cases 100 percent. Tuberculosis was absent in the small number of silver and chum salmon examined which were known to be the progeny from natural spawning. It is suggested that dissemination of the disease may be due to fish-cultural practices such as the feeding of untreated carcasses and the viscera from tuberculous fish. Since acid-fast bacilli were found in the roe of some fish, it is also suggested that the disease may be transmitted to healthy eggs during the process of fertilization. Tuberculous adult spring chinook were found less capable of surviving to maturity after they reached the spawning grounds than were non-infected fish. It is likely that tuberculosis also influences the ability of salmon to survive during earlier stages of their life history. The incidence of tuberculosis in adult spring chinook entering the Dexter holding ponds on the Middle Fork of the Willamette River in 1955 and 1956 was 8.7 and 6.1 percent, respectively. The increase in incidence to 58.8 percent in 1957 is attributed to the increased dependency of the run on artificial propagation necessitated by the construction of Lookout Point Dam. Among chinook caught in the Columbia River gill-net fishery in. February and in May 1956, 12.3 and 10.5 percent, respectively, of those examined were tuberculous. Although these are spring chinook, it is believed that hatchery reared fall chinook also entered the catch, especially during May, and may have contributed to the number of tuberculous fish taken. Close

• 2243. [Article] The fishery and biology of the Dungeness crab (Cancer magister Dana) in Oregon waters

  Results of studies beginning in 1947 on the biology of the Dungeness crab (Cancer magister) in Oregon coastal waters are reported. A review is made of the history of the fishery with regard to trend of ...

  Citation × Citation Citation Abstract Copy Title: The fishery and biology of the Dungeness crab (Cancer magister Dana) in Oregon waters Author: Oregon. Fish Commission, Waldron, Kenneth D. Results of studies beginning in 1947 on the biology of the Dungeness crab (Cancer magister) in Oregon coastal waters are reported. A review is made of the history of the fishery with regard to trend of the catch by magnitude, area, and season; the development and conduct of the fishery itself; and the regulations governing the fishery. The first reported commercial crab landings in Oregon were 6,628 pounds in 1880. The fishery expanded slowly until 1933 after which the catch rose sharply to a peak of about 11 million pounds in 1943. Landings in recent years have fluctuated between 6 and 11 million pounds from a commercial fishery which is carried out along the major portion of the Oregon coast. During the period 1947-50, 6,249 tagged crabs were released in offshore and bay waters of Oregon and 34.6 percent of the tags were subsequently recovered. The average movement of 1,042 recoveries of crabs released in offshore waters, as measured by the distance from the tagging site, was 8.3 miles (range 0-133 miles) in 80 days. For crabs released within bays, 606 recoveries averaged a minimum distance traveled of 4.2 miles (range 0-81 miles). Fifty-seven percent of the recoveries of offshore releases and 84 percent of the recoveries of bay releases were made within 4 miles of the respective tagging sites. Over 90 percent of the recoveries of offshore releases were made within 6 months, although 3 crabs were out more than a year with 1 at liberty 878 days. Tagged crabs moved from offshore to bays, from bay to bay, and from bays to offshore. There was no significant difference in percentage recovery for crabs with or without missing appendages. Egg-bearing female crabs are present in offshore waters during the period October to March, inclusive. Larval crabs assumed to be C. magister were observed in offshore waters from April to July, inclusive. Considerable variation in early growth of post larval crabs was observed in laboratory experiments. The amount of growth of crabs between 6.4 and 146.0 mm., as observed by measuring them before and after molting, increases until a shoulder width of about 95 mm. is reached. The increase with each subsequent molt thereafter remains relatively constant. Macroplankton-eating fishes feed upon free swimming crab larvae. Adult crabs up to at least 114 mm. in shoulder width are preyed upon by voracious fish such as ling-cod (Ophiodon elongatus), the great marbeled sculpin (Scorpaenichthys armoratus), wolf eel (Anarrhichthys ocellatus), halibut (Hippoglossus stenolepis), and some of the rock fishes of the genus Sebastodes. Title: The fishery and biology of the Dungeness crab (Cancer magister Dana) in Oregon waters Author: Oregon. Fish Commission, Waldron, Kenneth D. Results of studies beginning in 1947 on the biology of the Dungeness crab (Cancer magister) in Oregon coastal waters are reported. A review is made of the history of the fishery with regard to trend of the catch by magnitude, area, and season; the development and conduct of the fishery itself; and the regulations governing the fishery. The first reported commercial crab landings in Oregon were 6,628 pounds in 1880. The fishery expanded slowly until 1933 after which the catch rose sharply to a peak of about 11 million pounds in 1943. Landings in recent years have fluctuated between 6 and 11 million pounds from a commercial fishery which is carried out along the major portion of the Oregon coast. During the period 1947-50, 6,249 tagged crabs were released in offshore and bay waters of Oregon and 34.6 percent of the tags were subsequently recovered. The average movement of 1,042 recoveries of crabs released in offshore waters, as measured by the distance from the tagging site, was 8.3 miles (range 0-133 miles) in 80 days. For crabs released within bays, 606 recoveries averaged a minimum distance traveled of 4.2 miles (range 0-81 miles). Fifty-seven percent of the recoveries of offshore releases and 84 percent of the recoveries of bay releases were made within 4 miles of the respective tagging sites. Over 90 percent of the recoveries of offshore releases were made within 6 months, although 3 crabs were out more than a year with 1 at liberty 878 days. Tagged crabs moved from offshore to bays, from bay to bay, and from bays to offshore. There was no significant difference in percentage recovery for crabs with or without missing appendages. Egg-bearing female crabs are present in offshore waters during the period October to March, inclusive. Larval crabs assumed to be C. magister were observed in offshore waters from April to July, inclusive. Considerable variation in early growth of post larval crabs was observed in laboratory experiments. The amount of growth of crabs between 6.4 and 146.0 mm., as observed by measuring them before and after molting, increases until a shoulder width of about 95 mm. is reached. The increase with each subsequent molt thereafter remains relatively constant. Macroplankton-eating fishes feed upon free swimming crab larvae. Adult crabs up to at least 114 mm. in shoulder width are preyed upon by voracious fish such as ling-cod (Ophiodon elongatus), the great marbeled sculpin (Scorpaenichthys armoratus), wolf eel (Anarrhichthys ocellatus), halibut (Hippoglossus stenolepis), and some of the rock fishes of the genus Sebastodes. Close

• 2244. [Article] The Ecology of Celtis reticulata Torr. (Netleaf hackberry) in Idaho

  The ecology of netleaf hackberry (Celtis reticulata Torr.) is poorly known throughout its broad western range. To gain some understanding of the species' basic ecology, three components of its life history ...

  Citation × Citation Citation Abstract Copy Title: The Ecology of Celtis reticulata Torr. (Netleaf hackberry) in Idaho Author: DeBolt, Ann M. The ecology of netleaf hackberry (Celtis reticulata Torr.) is poorly known throughout its broad western range. To gain some understanding of the species' basic ecology, three components of its life history were studied. First, seed germination requirements were analyzed under laboratory conditions. Second, hackberry population dynamics were evaluated from tree size and age structures. Lastly, an examination of hackberry's response to fire was made, using tree-level post-fire data. A higher percentage of non-stratified hackberry seed germinates if the seed is mechanically scarified. While germination percent is low, the treatment may eliminate the 120-day stratification period recommended by some authorities. Even with cold stratification, germination is usually quite low for Celtis species. Fermenting fruits for 72 hours and subsequent depulping prior to scarification did not significantly increase germination levels, as hypothesized. However, seed that was not scarified but was fermented with its pulp intact germinated at a higher rate than the non-fermented, non-scarified seed. This result may be significant to its biology. Seed is typically cleaned prior to planting by seed distributors. However, hackberry seed with its pulp retained may in fact have a superior germination rate, as it is allowed to undergo natural processes of fermentation resulting from moist field conditions. In Idaho, hackberry's uniquely fragmented distribution appears to be controlled by a variety of factors. Hackberry is generally restricted to semi-arid portions of the state where temperatures are least severe during the winter months, such as in moderated river canyons, or at elevations below 1600 m. It occurs in a variety of habitats, from riparian to upland, however it is most abundant on sites with a southeast-to southwesterly aspect and a rocky surface cover. The presence of rock below the surface may be equally important, but this factor was not quantified. Hackberry is a slow-growing species in Idaho, averaging 3.9 m tall at 50 years. Differences in hackberry growth rate under a variety of site conditions were evaluated by a site index constructed from the log-log regression of height on age. Trees reach maximum heights where topographic shelter is greatest, such as in draws, and where soils are loamy. However, well-drained soils may be important, as nearly all soils had some sand or skeletal component. Hackberry can be long-lived, with the maximum age recorded at 374 years; the average age was 66 years (N = 959 trees). Hackberry appears to be reproducing, in spite of habitat degradation caused by livestock overgrazing, alien plant invasion, and increasing fire frequencies. However, newly established even-aged stands are rare and are generally found along waterways on stream terraces or at high water lines. In these areas, surface rock cover was typically high, with the rock providing a moderated below-ground microclimate, as well as protection from herbivores. Recruitment is favored by rockiness at the surface, but growth rates of established individuals are not higher with more surface rock. Under severe livestock grazing pressure, stands had a single dominant cohort and lowered recruitment. Fire-caused mortality of hackberry growing in low density stands appears to be uncommon in Idaho. In nine burns, only 8% of the trees (N = 161) were dead after the fires. This mortality, however, cannot be attributed solely to fire, as pre-burn vigor was not evaluated. Individuals typically persist or resprout following fire. Mortality rates were highest for individuals with a high percent cover of live vegetation below their canopy. Temperatures were probably more intense within the live vegetation, where the fire could feasibly linger long enough to kill the roots of the associated hackberry. While burns in high density stands were not observed, these burns could result in greater mortality, due to their greater continuity of plant cover. Title: The Ecology of Celtis reticulata Torr. (Netleaf hackberry) in Idaho Author: DeBolt, Ann M. The ecology of netleaf hackberry (Celtis reticulata Torr.) is poorly known throughout its broad western range. To gain some understanding of the species' basic ecology, three components of its life history were studied. First, seed germination requirements were analyzed under laboratory conditions. Second, hackberry population dynamics were evaluated from tree size and age structures. Lastly, an examination of hackberry's response to fire was made, using tree-level post-fire data. A higher percentage of non-stratified hackberry seed germinates if the seed is mechanically scarified. While germination percent is low, the treatment may eliminate the 120-day stratification period recommended by some authorities. Even with cold stratification, germination is usually quite low for Celtis species. Fermenting fruits for 72 hours and subsequent depulping prior to scarification did not significantly increase germination levels, as hypothesized. However, seed that was not scarified but was fermented with its pulp intact germinated at a higher rate than the non-fermented, non-scarified seed. This result may be significant to its biology. Seed is typically cleaned prior to planting by seed distributors. However, hackberry seed with its pulp retained may in fact have a superior germination rate, as it is allowed to undergo natural processes of fermentation resulting from moist field conditions. In Idaho, hackberry's uniquely fragmented distribution appears to be controlled by a variety of factors. Hackberry is generally restricted to semi-arid portions of the state where temperatures are least severe during the winter months, such as in moderated river canyons, or at elevations below 1600 m. It occurs in a variety of habitats, from riparian to upland, however it is most abundant on sites with a southeast-to southwesterly aspect and a rocky surface cover. The presence of rock below the surface may be equally important, but this factor was not quantified. Hackberry is a slow-growing species in Idaho, averaging 3.9 m tall at 50 years. Differences in hackberry growth rate under a variety of site conditions were evaluated by a site index constructed from the log-log regression of height on age. Trees reach maximum heights where topographic shelter is greatest, such as in draws, and where soils are loamy. However, well-drained soils may be important, as nearly all soils had some sand or skeletal component. Hackberry can be long-lived, with the maximum age recorded at 374 years; the average age was 66 years (N = 959 trees). Hackberry appears to be reproducing, in spite of habitat degradation caused by livestock overgrazing, alien plant invasion, and increasing fire frequencies. However, newly established even-aged stands are rare and are generally found along waterways on stream terraces or at high water lines. In these areas, surface rock cover was typically high, with the rock providing a moderated below-ground microclimate, as well as protection from herbivores. Recruitment is favored by rockiness at the surface, but growth rates of established individuals are not higher with more surface rock. Under severe livestock grazing pressure, stands had a single dominant cohort and lowered recruitment. Fire-caused mortality of hackberry growing in low density stands appears to be uncommon in Idaho. In nine burns, only 8% of the trees (N = 161) were dead after the fires. This mortality, however, cannot be attributed solely to fire, as pre-burn vigor was not evaluated. Individuals typically persist or resprout following fire. Mortality rates were highest for individuals with a high percent cover of live vegetation below their canopy. Temperatures were probably more intense within the live vegetation, where the fire could feasibly linger long enough to kill the roots of the associated hackberry. While burns in high density stands were not observed, these burns could result in greater mortality, due to their greater continuity of plant cover. Close

• 2245. [Article] The seismic vulnerability of sheet pile walls

  The seismic performance of port structures has been well documented following recent earthquakes, and indicates that port structures are highly susceptible to earthquake-induced damages. These damages ...

  Citation × Citation Citation Abstract Copy Title: The seismic vulnerability of sheet pile walls Author: McCullough, Nason J. The seismic performance of port structures has been well documented following recent earthquakes, and indicates that port structures are highly susceptible to earthquake-induced damages. These damages are primarily due to soil liquefaction and the associated ground failures. Sheet pile bulkheads provide vital intermodal and lifeline transportation links between water-side and land-side traffic, and are waterfront structures particularly vulnerable to liquefaction-induced damages. Due to the prevalence of liquefaction-induced damages, many ports are utilizing soil improvement techniques to mitigate these hazards. Many port authorities have proposed utilizing performance-based design criteria to limit potential earthquake-induced damages. The current design method for sheet pile walls (Mononobe-Okabe) is based on simple, limit equilibrium analysis techniques, which are poorly suited for performance-based design. Recent advancements in the seismic design of sheet pile walls have addressed some of the limitations of the current design methods, but are still inadequate for performing a complete, performance-based design for locations that contain potentially liquefiable soils and/or where soil improvement strategies have been instituted. This study has focused on conducting an empirical investigation and numerical modeling to determine the seismic performance of sheet pile walls, and the performancebased benefit of soil improvement through densification. A case history validated, nonlinear effective stress computer program was used to perform numerical parametric studies on various design parameters (earthquake properties, depth of sheet pile embedment, sheet pile wall stiffness, tie rod length, density of the backfill, and extent of soil densification). The results have been presented as a performance-based design method, and include a design chart that provides practitioners with a preliminary design tool that may be used to estimate the seismic deformations of sheet pile walls with or without soil improvement. The study has demonstrated that soil densification can greatly reduce the seismicallyinduced deformations, especially when the magnitude of soil improvement extends beyond the location of the anchor. The study has also demonstrated that the use of soil densification techniques for mitigating seismic hazards may not be adequate in limiting deformations to allowable limits, and that other methods of soil improvement (cementation, drainage, etc.) or structural improvements may also be required. Title: The seismic vulnerability of sheet pile walls Author: McCullough, Nason J. The seismic performance of port structures has been well documented following recent earthquakes, and indicates that port structures are highly susceptible to earthquake-induced damages. These damages are primarily due to soil liquefaction and the associated ground failures. Sheet pile bulkheads provide vital intermodal and lifeline transportation links between water-side and land-side traffic, and are waterfront structures particularly vulnerable to liquefaction-induced damages. Due to the prevalence of liquefaction-induced damages, many ports are utilizing soil improvement techniques to mitigate these hazards. Many port authorities have proposed utilizing performance-based design criteria to limit potential earthquake-induced damages. The current design method for sheet pile walls (Mononobe-Okabe) is based on simple, limit equilibrium analysis techniques, which are poorly suited for performance-based design. Recent advancements in the seismic design of sheet pile walls have addressed some of the limitations of the current design methods, but are still inadequate for performing a complete, performance-based design for locations that contain potentially liquefiable soils and/or where soil improvement strategies have been instituted. This study has focused on conducting an empirical investigation and numerical modeling to determine the seismic performance of sheet pile walls, and the performancebased benefit of soil improvement through densification. A case history validated, nonlinear effective stress computer program was used to perform numerical parametric studies on various design parameters (earthquake properties, depth of sheet pile embedment, sheet pile wall stiffness, tie rod length, density of the backfill, and extent of soil densification). The results have been presented as a performance-based design method, and include a design chart that provides practitioners with a preliminary design tool that may be used to estimate the seismic deformations of sheet pile walls with or without soil improvement. The study has demonstrated that soil densification can greatly reduce the seismicallyinduced deformations, especially when the magnitude of soil improvement extends beyond the location of the anchor. The study has also demonstrated that the use of soil densification techniques for mitigating seismic hazards may not be adequate in limiting deformations to allowable limits, and that other methods of soil improvement (cementation, drainage, etc.) or structural improvements may also be required. Close

• 2246. [Article] The kinetic and radiolytic aspects of control of the redox speciation of neptunium in solutions of nitric acid

  Neptunium, with its rich redox chemistry, has a special position in the chemistry of actinides. With a decades-long history of development of aqueous separation methods for used nuclear fuel (UNF), management ...

  Citation × Citation Citation Abstract Copy Title: The kinetic and radiolytic aspects of control of the redox speciation of neptunium in solutions of nitric acid Author: Precek, Martin Neptunium, with its rich redox chemistry, has a special position in the chemistry of actinides. With a decades-long history of development of aqueous separation methods for used nuclear fuel (UNF), management of neptunium remains an unresolved issue because of its not clearly defined redox speciation. Neptunium is present in two, pentavalent (V) and hexavalent (VI) oxidation states, both in their dioxocation O=Np=O neptunyl form, which differ greatly in their solvent extraction behavior. While the neptunium(VI) dioxocation is being very well extracted, the dioxocation of pentavalent neptunium is practically non-extractable by an organic solvent. As a result, neptunium is not well separated and remains distributed in both organic and aqueous extraction phases. The aim of this study was to develop or enhance the understanding of several key topics governing the redox behavior of neptunium in nitric acid medium, which are of vital importance for the engineering design of industrial-scale liquid-liquid separation systems. In this work, reactions of neptunium(V) and (VI) with vanadium(V) and acetohydroxamic acid - two redox agents envisioned for adjusting the neptunium oxidation state in aqueous separations – were studied in order to determine their kinetic characteristics, rate laws and rate constants, as a function of temperature and nitric acid concentration. Further were analyzed the interactions of neptunium(V) and (VI) with nitrous acid, which is formed as a product of radiolytic degradation of nitric acid caused by high levels of radioactivity present in such systems. Once HNO₃ is distributed between both the aqueous solutions and organic solvent, nitrous acid is also formed in both phases and has a key influence on redox speciation of neptunium; therefore, the effects of gamma-radiation on the redox speciation of neptunium were investigated. The work also includes the results of examination of scavenging of nitrous acid by hydrogen peroxide, which is generated along with nitrous acid during radiolysis of aqueous solutions of nitric acid, and also by chemical reactions with added scavenging agents (methylurea, acetohydroxamic acid). Title: The kinetic and radiolytic aspects of control of the redox speciation of neptunium in solutions of nitric acid Author: Precek, Martin Neptunium, with its rich redox chemistry, has a special position in the chemistry of actinides. With a decades-long history of development of aqueous separation methods for used nuclear fuel (UNF), management of neptunium remains an unresolved issue because of its not clearly defined redox speciation. Neptunium is present in two, pentavalent (V) and hexavalent (VI) oxidation states, both in their dioxocation O=Np=O neptunyl form, which differ greatly in their solvent extraction behavior. While the neptunium(VI) dioxocation is being very well extracted, the dioxocation of pentavalent neptunium is practically non-extractable by an organic solvent. As a result, neptunium is not well separated and remains distributed in both organic and aqueous extraction phases. The aim of this study was to develop or enhance the understanding of several key topics governing the redox behavior of neptunium in nitric acid medium, which are of vital importance for the engineering design of industrial-scale liquid-liquid separation systems. In this work, reactions of neptunium(V) and (VI) with vanadium(V) and acetohydroxamic acid - two redox agents envisioned for adjusting the neptunium oxidation state in aqueous separations – were studied in order to determine their kinetic characteristics, rate laws and rate constants, as a function of temperature and nitric acid concentration. Further were analyzed the interactions of neptunium(V) and (VI) with nitrous acid, which is formed as a product of radiolytic degradation of nitric acid caused by high levels of radioactivity present in such systems. Once HNO₃ is distributed between both the aqueous solutions and organic solvent, nitrous acid is also formed in both phases and has a key influence on redox speciation of neptunium; therefore, the effects of gamma-radiation on the redox speciation of neptunium were investigated. The work also includes the results of examination of scavenging of nitrous acid by hydrogen peroxide, which is generated along with nitrous acid during radiolysis of aqueous solutions of nitric acid, and also by chemical reactions with added scavenging agents (methylurea, acetohydroxamic acid). Close

• 2247. [Article] The feasibility of using diploid by tetraploid crosses to obtain triploid hops (Humulus lupulus L.)

  The hop (Humulus lupulus L.) is a dioecious, diploid (2n=2x=20) species. Triploid hops (2n=3x=30) are easily obtained from tetraploid by diploid crosses and are preferred because of their natural seedlessness ...

  Citation × Citation Citation Abstract Copy Title: The feasibility of using diploid by tetraploid crosses to obtain triploid hops (Humulus lupulus L.) Author: DeNoma, Jeanine Streeter The hop (Humulus lupulus L.) is a dioecious, diploid (2n=2x=20) species. Triploid hops (2n=3x=30) are easily obtained from tetraploid by diploid crosses and are preferred because of their natural seedlessness and increased vigor. The female inflorescence is used for flavoring beer. Because brewers require product consistency, the brewing characteristics of a new aroma-type hop must closely match the variety it is intended to replace while showing improved adaptation and agronomic traits. Since triploid offspring should more closely resemble the tetraploid parent from which they receive two-thirds of their genetic material, breeders have traditionally selected known varieties to be the tetraploid parent with the expectation this will increase the likelihood of obtaining progeny with similar brewing chemistry. Tetraploid female parents are obtained through colchicine treatment of desirable diploid varieties. Naturally occurring tetraploid seedlings, sometimes found among the offspring of tetraploid by diploid crosses, if suitable for breeding, could eliminate the tedious colchicine treatment process now used to obtain tetraploids. Two such tetraploid males were obtained from an Oregon cross in 1983. Since these two tetraploid males had attractive quality traits similar to other males in the USDA germplasm collection with a proven history of producing aroma-type progeny, they were thought to be suitable for use in a polyploid breeding program for aroma hops. The objective of this study was to determine the feasibility of using males as tetraploid parents in diploid by tetraploid crosses to obtain triploid aroma hops. Tettnanger, a prized German aroma hop, was used as the diploid female parent for these crosses. Meiotic cells of the two tetraploid males showed some abnormalities at anaphase I and the quartet stage; however, fertility, as determined from seed production and germination, was adequate for breeding. Of 185 seedlings obtained, 57 were triploid females. The diploid by tetraploid seedling population had a higher percentage of males than previously reported for tetraploid by diploid crosses. One tetraploid male produced no triploid female offspring. Seed content of the female triploid seedlings when subjected to a heavy pollen load averaged 2.4% compared to 20.1% for diploid seedlings from Tettnanger crosses. Triploid progeny produced higher average yield than the Tettnanger parent. The two tetraploid males and Tettnanger were very similar in chemical quality traits comparable in male and female hops. Comparison among triploid and diploid progeny from diploid by tetraploid crosses and diploid open-pollinated Tettnanger seedlings demonstrated that the male parent influenced the a ratio, cohumulone content, and humulene to caryophyllene ratio of the offspring. Many of the female triploid offspring genotypes showed chemical quality traits similar to those of Tettnanger. Title: The feasibility of using diploid by tetraploid crosses to obtain triploid hops (Humulus lupulus L.) Author: DeNoma, Jeanine Streeter The hop (Humulus lupulus L.) is a dioecious, diploid (2n=2x=20) species. Triploid hops (2n=3x=30) are easily obtained from tetraploid by diploid crosses and are preferred because of their natural seedlessness and increased vigor. The female inflorescence is used for flavoring beer. Because brewers require product consistency, the brewing characteristics of a new aroma-type hop must closely match the variety it is intended to replace while showing improved adaptation and agronomic traits. Since triploid offspring should more closely resemble the tetraploid parent from which they receive two-thirds of their genetic material, breeders have traditionally selected known varieties to be the tetraploid parent with the expectation this will increase the likelihood of obtaining progeny with similar brewing chemistry. Tetraploid female parents are obtained through colchicine treatment of desirable diploid varieties. Naturally occurring tetraploid seedlings, sometimes found among the offspring of tetraploid by diploid crosses, if suitable for breeding, could eliminate the tedious colchicine treatment process now used to obtain tetraploids. Two such tetraploid males were obtained from an Oregon cross in 1983. Since these two tetraploid males had attractive quality traits similar to other males in the USDA germplasm collection with a proven history of producing aroma-type progeny, they were thought to be suitable for use in a polyploid breeding program for aroma hops. The objective of this study was to determine the feasibility of using males as tetraploid parents in diploid by tetraploid crosses to obtain triploid aroma hops. Tettnanger, a prized German aroma hop, was used as the diploid female parent for these crosses. Meiotic cells of the two tetraploid males showed some abnormalities at anaphase I and the quartet stage; however, fertility, as determined from seed production and germination, was adequate for breeding. Of 185 seedlings obtained, 57 were triploid females. The diploid by tetraploid seedling population had a higher percentage of males than previously reported for tetraploid by diploid crosses. One tetraploid male produced no triploid female offspring. Seed content of the female triploid seedlings when subjected to a heavy pollen load averaged 2.4% compared to 20.1% for diploid seedlings from Tettnanger crosses. Triploid progeny produced higher average yield than the Tettnanger parent. The two tetraploid males and Tettnanger were very similar in chemical quality traits comparable in male and female hops. Comparison among triploid and diploid progeny from diploid by tetraploid crosses and diploid open-pollinated Tettnanger seedlings demonstrated that the male parent influenced the a ratio, cohumulone content, and humulene to caryophyllene ratio of the offspring. Many of the female triploid offspring genotypes showed chemical quality traits similar to those of Tettnanger. Close

• 2248. [Article] A comparative study of the factors relating to post high school educational pursuits of selected American Indians : some characteristics and self-perceptions

  A unique aspect of this study is that it involves an unusually large number of individuals of American Indian descent. The sample population was composed of those Indian members of the 1962 high school ...

  Citation × Citation Citation Abstract Copy Title: A comparative study of the factors relating to post high school educational pursuits of selected American Indians : some characteristics and self-perceptions Author: Hathhorn, James Robert A unique aspect of this study is that it involves an unusually large number of individuals of American Indian descent. The sample population was composed of those Indian members of the 1962 high school graduating class from a six-state area. The selected graduates came from local public, Bureau of Indian Affairs, and private secondary schools located in Oregon, Washington, Idaho, Montana, North Dakota and South Dakota. The graduates of the 1962 class were selected to be studied as they would have completed their educational experiences or become employed in a selected vocation and would have established a life style. The model used for data collection was designed and completed in large part by Indians. The data were collected in two parts. The first part was information of an autobiographical nature and was oriented to characteristics that included the usual vital statistics, degree of blood quantum, residence at time of interview, ability to speak an Indian language, importance of speaking an Indian language, etc. The second part of the data collected was information gathered by interviews and involved those factors of self-perception such as effect of peer group association, attained success, source of information on post high school education, educational and employment opportunities, etc. Half of the total sample population was asked to respond to 84 questions. When tabulated, significant statistical difference was found in 15 of the questions. In five categories of questions, the calculations indicated that chi square values at the .05 level of statistical significance occurred. The remaining ten calculations have chi square values at the .01 level of statistical significance. In the analysis of the areas where significant statistical differences were observed, only three questions could be classified in the areas defined as characteristics. The conclusion was reached that the Indian has been assimilated into the dominant culture in far greater degree than even the Indian realizes or is willing to admit. The remaining categories of questions, where significant statistical differences were indicated, occurred in the area of self-perception. These differences reaffirmed the conclusion that the Indian high school graduate perceived the educational experience in a negative manner. Another conclusion drawn was that the Indian's low self-image is being reinforced by his formal education. The Indian is becoming increasingly cognizant of this disparity although there have been great sums of money and effort expended to assist the Indian in overcoming these negative self-perceptions. Inherent throughout the individual responses dealing with the Indians' self-perceptions, the underlying but obvious theme was that the formal education being received was not meeting the needs of individuals. Thus, Indians could not successfully compete in employment or advanced educational opportunities. These deficiencies were perceived as detrimental to the individual Indian and are contrary to the philosophical objectives of secondary education in the United States. One of the stated objectives of Indians is to be educated and therefore able to compete on equal terms for educational and employment opportunities within the dominant society. Another goal is to retain as much of their culture as is possible to maintain and develop their Indian identity. The long history of the dominant society's attitude toward the Indian and his education is one of debasement which leaves a stigma on the individual. Such an attitude tends to minimize the Indian's individual goals and potential for self-direction, creativity, and flexibility in educational opportunity and newly emerging life styles. Title: A comparative study of the factors relating to post high school educational pursuits of selected American Indians : some characteristics and self-perceptions Author: Hathhorn, James Robert A unique aspect of this study is that it involves an unusually large number of individuals of American Indian descent. The sample population was composed of those Indian members of the 1962 high school graduating class from a six-state area. The selected graduates came from local public, Bureau of Indian Affairs, and private secondary schools located in Oregon, Washington, Idaho, Montana, North Dakota and South Dakota. The graduates of the 1962 class were selected to be studied as they would have completed their educational experiences or become employed in a selected vocation and would have established a life style. The model used for data collection was designed and completed in large part by Indians. The data were collected in two parts. The first part was information of an autobiographical nature and was oriented to characteristics that included the usual vital statistics, degree of blood quantum, residence at time of interview, ability to speak an Indian language, importance of speaking an Indian language, etc. The second part of the data collected was information gathered by interviews and involved those factors of self-perception such as effect of peer group association, attained success, source of information on post high school education, educational and employment opportunities, etc. Half of the total sample population was asked to respond to 84 questions. When tabulated, significant statistical difference was found in 15 of the questions. In five categories of questions, the calculations indicated that chi square values at the .05 level of statistical significance occurred. The remaining ten calculations have chi square values at the .01 level of statistical significance. In the analysis of the areas where significant statistical differences were observed, only three questions could be classified in the areas defined as characteristics. The conclusion was reached that the Indian has been assimilated into the dominant culture in far greater degree than even the Indian realizes or is willing to admit. The remaining categories of questions, where significant statistical differences were indicated, occurred in the area of self-perception. These differences reaffirmed the conclusion that the Indian high school graduate perceived the educational experience in a negative manner. Another conclusion drawn was that the Indian's low self-image is being reinforced by his formal education. The Indian is becoming increasingly cognizant of this disparity although there have been great sums of money and effort expended to assist the Indian in overcoming these negative self-perceptions. Inherent throughout the individual responses dealing with the Indians' self-perceptions, the underlying but obvious theme was that the formal education being received was not meeting the needs of individuals. Thus, Indians could not successfully compete in employment or advanced educational opportunities. These deficiencies were perceived as detrimental to the individual Indian and are contrary to the philosophical objectives of secondary education in the United States. One of the stated objectives of Indians is to be educated and therefore able to compete on equal terms for educational and employment opportunities within the dominant society. Another goal is to retain as much of their culture as is possible to maintain and develop their Indian identity. The long history of the dominant society's attitude toward the Indian and his education is one of debasement which leaves a stigma on the individual. Such an attitude tends to minimize the Indian's individual goals and potential for self-direction, creativity, and flexibility in educational opportunity and newly emerging life styles. Close

• 2249. [Article] Studies on some digenetic trematodes from Ritner Creek, Polk County, Oregon

  Seven species of fresh water fishes belonging to three different families and two species of snails from Ritner Creek, Polk County, Oregon were surveyed for adult and larval trematodes. A total of seven ...

  Citation × Citation Citation Abstract Copy Title: Studies on some digenetic trematodes from Ritner Creek, Polk County, Oregon Author: Law, Daniel Tin-Hung Seven species of fresh water fishes belonging to three different families and two species of snails from Ritner Creek, Polk County, Oregon were surveyed for adult and larval trematodes. A total of seven species of trematodes representing four families was recovered from the intestine of the fishes. Of these, at least two were under scribed new species. The trematodes were described and their taxonomy discussed. The stream snails, Oxytrema silicula and Flumenicola virens, were found to harbor at least 17 apparent species of larval trematodes. Five of these were described from the snails for the first time. A check-list of cercariae known to infect O. silicula and F. virens in the Pacific Northwest was presented. Life histories of five of the trematodes .encountered during the surveys were studied. The experimental life cycle of Apophallus donicus Skrjabin and Lindtrop, 1919 was completed. The cercaria, of the pleurolophocercous group, was found in F. virens, while the metacercaria encysted in a number of fresh water fishes. The life cycle of Plagioporus siliculus Sinitsin, 1931 was demonstrated for the first time. The cotylomicrocercous cercaria developed in sporocyst in O. silicula and penetrated crayfish, Pacifastacus lenuisculus to encyst in the abdominal muscles. The experimental definitive host used was the rainbow trout. A single adult Echinochasmus milvi Yamaguti, 1939 was recovered from a duck fed echinostome cysts found naturally in the gills of blackside dace, Rhinichthys osculus nubilus and redside shiner, Richardsoni balteatus hydrophlox. This constituted the third record of the trematode in the Pacific Northwest. The cercaria of E. milvi was believed to be Cercaria gorgonocephala Ward, 1916, which Martin (1968) redescribed from O. silicula. Two other macrocercous cercariae--one aggregating but albino while the other nonaggregating-- were also found in O. silicula, The body of these cercariae was identical to that of C. gorgonocephala. The taxonomic relation of the three cercariae was discussed. The partial life cycle of a new monorchiid trematode from the torrent sculpin, Cottus rhotheus, was presented. The natural secondary intermediate host was found to be lampreys, both brook (Lampetra richardsoni) and Pacific (L. tridentata). The first intermediate host is still unknown. The partial life cycle of another new trematode, an Echinochasmus sp., was also reported. The adult was obtained from a duck experimentally fed small cysts in the gills of blackside dace. The first intermediate host is unknown. Title: Studies on some digenetic trematodes from Ritner Creek, Polk County, Oregon Author: Law, Daniel Tin-Hung Seven species of fresh water fishes belonging to three different families and two species of snails from Ritner Creek, Polk County, Oregon were surveyed for adult and larval trematodes. A total of seven species of trematodes representing four families was recovered from the intestine of the fishes. Of these, at least two were under scribed new species. The trematodes were described and their taxonomy discussed. The stream snails, Oxytrema silicula and Flumenicola virens, were found to harbor at least 17 apparent species of larval trematodes. Five of these were described from the snails for the first time. A check-list of cercariae known to infect O. silicula and F. virens in the Pacific Northwest was presented. Life histories of five of the trematodes .encountered during the surveys were studied. The experimental life cycle of Apophallus donicus Skrjabin and Lindtrop, 1919 was completed. The cercaria, of the pleurolophocercous group, was found in F. virens, while the metacercaria encysted in a number of fresh water fishes. The life cycle of Plagioporus siliculus Sinitsin, 1931 was demonstrated for the first time. The cotylomicrocercous cercaria developed in sporocyst in O. silicula and penetrated crayfish, Pacifastacus lenuisculus to encyst in the abdominal muscles. The experimental definitive host used was the rainbow trout. A single adult Echinochasmus milvi Yamaguti, 1939 was recovered from a duck fed echinostome cysts found naturally in the gills of blackside dace, Rhinichthys osculus nubilus and redside shiner, Richardsoni balteatus hydrophlox. This constituted the third record of the trematode in the Pacific Northwest. The cercaria of E. milvi was believed to be Cercaria gorgonocephala Ward, 1916, which Martin (1968) redescribed from O. silicula. Two other macrocercous cercariae--one aggregating but albino while the other nonaggregating-- were also found in O. silicula, The body of these cercariae was identical to that of C. gorgonocephala. The taxonomic relation of the three cercariae was discussed. The partial life cycle of a new monorchiid trematode from the torrent sculpin, Cottus rhotheus, was presented. The natural secondary intermediate host was found to be lampreys, both brook (Lampetra richardsoni) and Pacific (L. tridentata). The first intermediate host is still unknown. The partial life cycle of another new trematode, an Echinochasmus sp., was also reported. The adult was obtained from a duck experimentally fed small cysts in the gills of blackside dace. The first intermediate host is unknown. Close

• 2250. [Article] A clinical and genetic study of tuberous sclerosis

  Tuberous sclerosis is a serious heritable human disorder that involves many organ systems. It was first recognized as a disease entity over a century ago. Its mode of transmission in familial cases has ...

  Citation × Citation Citation Abstract Copy Title: A clinical and genetic study of tuberous sclerosis Author: Edwards, Thomas Allen Tuberous sclerosis is a serious heritable human disorder that involves many organ systems. It was first recognized as a disease entity over a century ago. Its mode of transmission in familial cases has been fairly well established to be that of a single gene locus autosomal dominant trait. However, the majority of cases reported in the medical literature have been found to be of de novo mutational origin. The finding of a high proportion of these sporadic cases was confirmed in the present study and is consistent with the markedly lowered fertility of affected individuals. The population of the Oregon State Fairview Hospital and Training Center, the state institution for the mentally retarded, was investigated relative to the incidence of patients with tuberous sclerosis and the clinical, radiological and genetic aspects of the ten propositi were evaluated. Two parents of the ten index cases were found to be affected with the disease thereby bringing the: total of ascertained cases to 12. This number of affected residents represents an incidence in Oregon of about 1 per 175,000 and this estimate is probably lower than the actual frequency of tuberous sclerosis in the state. Yet, this incidence is approximately comparable to that reported in several published reviews of tuberous sclerosis in other countries. Physical and radiographic examinations were accomplished for the index cases. All available relatives (77 percent of living relatives) of the propositi were examined and photographed. Skull x-rays of the two affected parents revealed intracranial calcifications typical of the disorder. A majority of the ten propositi exhibited dermatological legions such as a typical facial rash, fibromata of the fingers and toes, "sharkskin-like" plaques, depigmented areas and cafe-au-lait spots. All affected individuals were found to display x-ray abnormalities with intracranial calcifications being the most frequently found radiographic lesion. Implications derived from this study regarding genetic counseling of affected persons and their families are discussed with emphasis on the importance of a thorough genetic history, complete medical examination of the patient and of close relatives; and, where indicated, selected x-rays of the affected person and relatives considered to be possible carriers of the trait. The wide spectrum of expressivity for this condition must be borne in mind when carrying out a genetic analysis. With the present limited knowledge regarding the causation of "spontaneous point mutations" and the lack of effective measures to prevent such de novo genetic aberrations, it is not feasible to diminish the frequency of sporadic cases of tuberous sclerosis. On the other hand, correct diagnosis and appropriate genetic counseling should allow a significant decrease in the transmission of this trait to the progeny of affected persons and should permit reassurance of relatives of sporadic cases regarding the risk of recurrence in these families. However, the usual precautions pertaining to the designation of any affected individual as a sporadic rather than a familial case must be followed and this admonition is particularly relevant to a heritable disorder with marked variability of expressivity as is the case for tuberous sclerosis. Title: A clinical and genetic study of tuberous sclerosis Author: Edwards, Thomas Allen Tuberous sclerosis is a serious heritable human disorder that involves many organ systems. It was first recognized as a disease entity over a century ago. Its mode of transmission in familial cases has been fairly well established to be that of a single gene locus autosomal dominant trait. However, the majority of cases reported in the medical literature have been found to be of de novo mutational origin. The finding of a high proportion of these sporadic cases was confirmed in the present study and is consistent with the markedly lowered fertility of affected individuals. The population of the Oregon State Fairview Hospital and Training Center, the state institution for the mentally retarded, was investigated relative to the incidence of patients with tuberous sclerosis and the clinical, radiological and genetic aspects of the ten propositi were evaluated. Two parents of the ten index cases were found to be affected with the disease thereby bringing the: total of ascertained cases to 12. This number of affected residents represents an incidence in Oregon of about 1 per 175,000 and this estimate is probably lower than the actual frequency of tuberous sclerosis in the state. Yet, this incidence is approximately comparable to that reported in several published reviews of tuberous sclerosis in other countries. Physical and radiographic examinations were accomplished for the index cases. All available relatives (77 percent of living relatives) of the propositi were examined and photographed. Skull x-rays of the two affected parents revealed intracranial calcifications typical of the disorder. A majority of the ten propositi exhibited dermatological legions such as a typical facial rash, fibromata of the fingers and toes, "sharkskin-like" plaques, depigmented areas and cafe-au-lait spots. All affected individuals were found to display x-ray abnormalities with intracranial calcifications being the most frequently found radiographic lesion. Implications derived from this study regarding genetic counseling of affected persons and their families are discussed with emphasis on the importance of a thorough genetic history, complete medical examination of the patient and of close relatives; and, where indicated, selected x-rays of the affected person and relatives considered to be possible carriers of the trait. The wide spectrum of expressivity for this condition must be borne in mind when carrying out a genetic analysis. With the present limited knowledge regarding the causation of "spontaneous point mutations" and the lack of effective measures to prevent such de novo genetic aberrations, it is not feasible to diminish the frequency of sporadic cases of tuberous sclerosis. On the other hand, correct diagnosis and appropriate genetic counseling should allow a significant decrease in the transmission of this trait to the progeny of affected persons and should permit reassurance of relatives of sporadic cases regarding the risk of recurrence in these families. However, the usual precautions pertaining to the designation of any affected individual as a sporadic rather than a familial case must be followed and this admonition is particularly relevant to a heritable disorder with marked variability of expressivity as is the case for tuberous sclerosis. Close