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• 41. [Article] A study of attitude stability of a symmetrical satellite in a circular orbit

  A model for analytical study of the attitude stability of an orbiting satellite consists of a rigid body whose mass center is constrained to move at constant speed in a circular path about the center of ...

  Citation × Citation Citation Abstract Copy Title: A study of attitude stability of a symmetrical satellite in a circular orbit Author: Wang, Hsien-tsan A model for analytical study of the attitude stability of an orbiting satellite consists of a rigid body whose mass center is constrained to move at constant speed in a circular path about the center of an inverse-square force field. The body is assumed to have one axis of inertial symmetry. It is of primary interest here to determine whether the attitude of this symmetric axis is stable in its various equilibrium positions. The stability depends upon two parameters: the ratio of spin velocity about the symmetry axis to orbital angular velocity, and the ratio of the two moments of inertia of the satellite. The equations of motion which govern the deviations of the symmetry axis from its equilibrium configuration are nonlinear in nature. When linearized, the equations show instability in some regions, but everywhere else, the linear approximation is a "critical case" in which the roots of the characteristic equation all have zero real part. When complete nonlinear equations are investigated by means of the direct method of Lyapunov, some region can be specified as Lyapunov stable by using the Hamiltonian function as a Lyapunov function, while there remains a sizeable region where the stability has not been determined, as shown in papers by Pringle and Likins, When equations which are approximated by third and fifth powers are investigated by a series of transformations following Malkin's approach, it is found that if there is instability in the remainder of plane where no conclusion is yet available, it is very weak. Title: A study of attitude stability of a symmetrical satellite in a circular orbit Author: Wang, Hsien-tsan A model for analytical study of the attitude stability of an orbiting satellite consists of a rigid body whose mass center is constrained to move at constant speed in a circular path about the center of an inverse-square force field. The body is assumed to have one axis of inertial symmetry. It is of primary interest here to determine whether the attitude of this symmetric axis is stable in its various equilibrium positions. The stability depends upon two parameters: the ratio of spin velocity about the symmetry axis to orbital angular velocity, and the ratio of the two moments of inertia of the satellite. The equations of motion which govern the deviations of the symmetry axis from its equilibrium configuration are nonlinear in nature. When linearized, the equations show instability in some regions, but everywhere else, the linear approximation is a "critical case" in which the roots of the characteristic equation all have zero real part. When complete nonlinear equations are investigated by means of the direct method of Lyapunov, some region can be specified as Lyapunov stable by using the Hamiltonian function as a Lyapunov function, while there remains a sizeable region where the stability has not been determined, as shown in papers by Pringle and Likins, When equations which are approximated by third and fifth powers are investigated by a series of transformations following Malkin's approach, it is found that if there is instability in the remainder of plane where no conclusion is yet available, it is very weak. Close

• 42. [Article] Biology and adult variability in an Oregon population of Leptarctiacaliforniae (Walker) (Lepidoptera: Arctiidae)

  Leptarctia californiae (Walker) was studied on clear and semi-forested southern slopes in the Coast Range Mountains of Benton County, Oregon. The spring of 1965 had an unusually long warm period (21 days) resulting ...

  Citation × Citation Citation Abstract Copy Title: Biology and adult variability in an Oregon population of Leptarctiacaliforniae (Walker) (Lepidoptera: Arctiidae) Author: Mays, David Lee Leptarctia californiae (Walker) was studied on clear and semi-forested southern slopes in the Coast Range Mountains of Benton County, Oregon. The spring of 1965 had an unusually long warm period (21 days) resulting in adult emergence approximately 25 days earlier than in the cooler spring of 1966. Peak flight activity occurred between 12:00 noon and 3:00 p.m. PST. Pheromone emission by females appeared to be the mechanism of male attraction. Larval developmental time in the laboratory (65-80°F) required approximately 60 days, which was 60 per cent longer than development under field conditions. First, second, and third instar larvae fed both day and night on low growing plants while fourth and fifth instars fad nocturnally on other plant species up to 18 inches above ground level. Dorsal hind wing colors in both males and females are black on black and yellow. In addition, females also have combinations of black with yellow- orange, orange, or red. Title: Biology and adult variability in an Oregon population of Leptarctiacaliforniae (Walker) (Lepidoptera: Arctiidae) Author: Mays, David Lee Leptarctia californiae (Walker) was studied on clear and semi-forested southern slopes in the Coast Range Mountains of Benton County, Oregon. The spring of 1965 had an unusually long warm period (21 days) resulting in adult emergence approximately 25 days earlier than in the cooler spring of 1966. Peak flight activity occurred between 12:00 noon and 3:00 p.m. PST. Pheromone emission by females appeared to be the mechanism of male attraction. Larval developmental time in the laboratory (65-80°F) required approximately 60 days, which was 60 per cent longer than development under field conditions. First, second, and third instar larvae fed both day and night on low growing plants while fourth and fifth instars fad nocturnally on other plant species up to 18 inches above ground level. Dorsal hind wing colors in both males and females are black on black and yellow. In addition, females also have combinations of black with yellow- orange, orange, or red. Close

• 43. [Article] Hydrologic factors and environmental impacts of mass soil movements in the Oregon Coast Range

  Mass soil movements of four types; debris avalanche, debris torrent, debris slide and bank slough, were field inventoried in the Oregon Coast Range. A total of 104 mass movements were located in 21 undisturbed ...

  Citation × Citation Citation Abstract Copy Title: Hydrologic factors and environmental impacts of mass soil movements in the Oregon Coast Range Author: Ketcheson, Gary Leslie Mass soil movements of four types; debris avalanche, debris torrent, debris slide and bank slough, were field inventoried in the Oregon Coast Range. A total of 104 mass movements were located in 21 undisturbed watersheds and 13 clearcuts harvested in the last six years. Failures associated with roads and landings were not included in this inventory. Failure volume ranged from 2 yd³ to 196 yd³. The average volume of all failure types ten cubic yards or more in volume is 41 yd³ in undisturbed watersheds and 47 yd³ in clearcuts. Failures less than ten cubic yards are of little significance in terms of initial volume moved, but in undisturbed watersheds they account for over one-fourth of the channel impact by mechanical scour and deposition. The frequency of all failures is similar in clearcuts and undisturbed watersheds, one in 19 acres and one in 17 acres, respectively. Mass failures travel 1.7 times farther in clearcuts than in undisturbed watersheds. Debris jams from failures in clearcuts contain. 3.2 times more inorganic and 2.5 times more organic debris than debris fans from undisturbed watersheds. Eight percent of the Class III and IV stream length (U. S Forest Service Classification) in forested drainages and ten percent of that within clearcuts is impacted by channel scour and deposition. The erosion rate for all soil landtypes encountered in undisturbed 3 watersheds is 0.11 yd³/ac/yr. This rate increases by 3.5 times in clearcuts. Landtypes with very steep, highly dissected slopes show the largest increase in erosion rate from uncut to clearcut watersheds (10 times). Less than one percent of the forested or clearcut land area is affected by the mass soil movements. Half of the failures in undisturbed drainages and nine-tenths of the failures in clearcuts occurred on slopes of 80 percent or greater. The average volume of failures is greatest on slopes of 80 to 100 percent. No apparent relation exists between. failure frequency and aspect in this study. The results are compared with other studies in. the Pacific Northwest and the differences are discussed. Natural variation accounts for much of the differences. Guidelines are given for assessing the risk of damage by debris avalanche and torrent type failures in proposed timber harvest areas. Title: Hydrologic factors and environmental impacts of mass soil movements in the Oregon Coast Range Author: Ketcheson, Gary Leslie Mass soil movements of four types; debris avalanche, debris torrent, debris slide and bank slough, were field inventoried in the Oregon Coast Range. A total of 104 mass movements were located in 21 undisturbed watersheds and 13 clearcuts harvested in the last six years. Failures associated with roads and landings were not included in this inventory. Failure volume ranged from 2 yd³ to 196 yd³. The average volume of all failure types ten cubic yards or more in volume is 41 yd³ in undisturbed watersheds and 47 yd³ in clearcuts. Failures less than ten cubic yards are of little significance in terms of initial volume moved, but in undisturbed watersheds they account for over one-fourth of the channel impact by mechanical scour and deposition. The frequency of all failures is similar in clearcuts and undisturbed watersheds, one in 19 acres and one in 17 acres, respectively. Mass failures travel 1.7 times farther in clearcuts than in undisturbed watersheds. Debris jams from failures in clearcuts contain. 3.2 times more inorganic and 2.5 times more organic debris than debris fans from undisturbed watersheds. Eight percent of the Class III and IV stream length (U. S Forest Service Classification) in forested drainages and ten percent of that within clearcuts is impacted by channel scour and deposition. The erosion rate for all soil landtypes encountered in undisturbed 3 watersheds is 0.11 yd³/ac/yr. This rate increases by 3.5 times in clearcuts. Landtypes with very steep, highly dissected slopes show the largest increase in erosion rate from uncut to clearcut watersheds (10 times). Less than one percent of the forested or clearcut land area is affected by the mass soil movements. Half of the failures in undisturbed drainages and nine-tenths of the failures in clearcuts occurred on slopes of 80 percent or greater. The average volume of failures is greatest on slopes of 80 to 100 percent. No apparent relation exists between. failure frequency and aspect in this study. The results are compared with other studies in. the Pacific Northwest and the differences are discussed. Natural variation accounts for much of the differences. Guidelines are given for assessing the risk of damage by debris avalanche and torrent type failures in proposed timber harvest areas. Close

• 44. [Article] Sediment production from forest roads in the upper Oak Creek Watershed of the Oregon Coast Range

  Unpaved roads are sources of chronic sediment in forested watersheds. Bare soil on roads is exposed to erosion from rainfall and runoff Published research on sediment production from forest roads focuses ...

  Citation × Citation Citation Abstract Copy Title: Sediment production from forest roads in the upper Oak Creek Watershed of the Oregon Coast Range Author: Amann, Joseph R. Unpaved roads are sources of chronic sediment in forested watersheds. Bare soil on roads is exposed to erosion from rainfall and runoff Published research on sediment production from forest roads focuses primarily on road characteristics. Since water drives the mechanics of sediment transport, hydrologic variables should correlate with sediment production. This project investigated the relationship between sediment production and runoff-producing storms. Road and hydrologic variables were correlated with total sediment production for nine road segments in the upper Oak Creek Watershed from November 2002 through June 2003. One of the road segments was monitored intensively during four runoff-producing storms. Field data were compared with total sediment production predicted by SEDMODL2 and WEPP:Road. Total coarse and settleable sediment produced from the nine road segments ranged from 0.025 kg (2.77 x 10⁻⁶ kg/m²/mo) to 15.0 kg (1.04 x 10-² kg/m²/mo) while total runoff volume ranged from 100 m³ (1.11 x 10⁻² m³/m²/mo) to 52,000 m³ (36.1 m³/m²/mo). Correlation between total coarse and settleable sediment and total runoff volume for all road segments was significant (R² = 0.51, p-value = 0.004). No other variables correlated as strongly with total coarse and settleable sediment. However, while hillslope gradient and cutslope height did not yield significant correlations with total coarse and settleable sediment as individual variables, when added to total runoff volume in a multiple linear regression model, the relationship was improved. Suspended sediment data was collected for four storms at one culvert. Results showed that suspended sediment concentration had time derivatives similar to those of culvert discharge, 1-hr rainfall intensity lagged one hour, and 2-hr rainfall intensity lagged two hours. Summed instantaneous suspended sediment concentration was correlated with cumulative rainfall. SEDMODL2 results of predicted sediment produced from the nine road segments ranged from 0.0 to 6.7 kg (4.4 x 10⁻⁴ kg/m²/mo). WEPP:Road results ranged from 160 kg (7.4 x 10⁻² kg/m²/mo) to 3020 kg (19.5 x 10⁻² kg/m²/mo). When compared with actual sediment data (0.025 kg to 15.0 kg), SEDMODL2 had much closer agreement. Further research is needed to quantify the total amount of suspended mineral sediment transported in runoff from unpaved forest roads in the upper Oak Creek Watershed. Title: Sediment production from forest roads in the upper Oak Creek Watershed of the Oregon Coast Range Author: Amann, Joseph R. Unpaved roads are sources of chronic sediment in forested watersheds. Bare soil on roads is exposed to erosion from rainfall and runoff Published research on sediment production from forest roads focuses primarily on road characteristics. Since water drives the mechanics of sediment transport, hydrologic variables should correlate with sediment production. This project investigated the relationship between sediment production and runoff-producing storms. Road and hydrologic variables were correlated with total sediment production for nine road segments in the upper Oak Creek Watershed from November 2002 through June 2003. One of the road segments was monitored intensively during four runoff-producing storms. Field data were compared with total sediment production predicted by SEDMODL2 and WEPP:Road. Total coarse and settleable sediment produced from the nine road segments ranged from 0.025 kg (2.77 x 10⁻⁶ kg/m²/mo) to 15.0 kg (1.04 x 10-² kg/m²/mo) while total runoff volume ranged from 100 m³ (1.11 x 10⁻² m³/m²/mo) to 52,000 m³ (36.1 m³/m²/mo). Correlation between total coarse and settleable sediment and total runoff volume for all road segments was significant (R² = 0.51, p-value = 0.004). No other variables correlated as strongly with total coarse and settleable sediment. However, while hillslope gradient and cutslope height did not yield significant correlations with total coarse and settleable sediment as individual variables, when added to total runoff volume in a multiple linear regression model, the relationship was improved. Suspended sediment data was collected for four storms at one culvert. Results showed that suspended sediment concentration had time derivatives similar to those of culvert discharge, 1-hr rainfall intensity lagged one hour, and 2-hr rainfall intensity lagged two hours. Summed instantaneous suspended sediment concentration was correlated with cumulative rainfall. SEDMODL2 results of predicted sediment produced from the nine road segments ranged from 0.0 to 6.7 kg (4.4 x 10⁻⁴ kg/m²/mo). WEPP:Road results ranged from 160 kg (7.4 x 10⁻² kg/m²/mo) to 3020 kg (19.5 x 10⁻² kg/m²/mo). When compared with actual sediment data (0.025 kg to 15.0 kg), SEDMODL2 had much closer agreement. Further research is needed to quantify the total amount of suspended mineral sediment transported in runoff from unpaved forest roads in the upper Oak Creek Watershed. Close

• 45. [Article] Seasonal Occurrence and Abundance of Insect Pests and Natural Enemies in the Columbia Basin

  Potato (Solanum tuberosum L.) is the fourth largest food crop in the world following rice (Oryza sativa L.), wheat (Triticum spp.), and maize (Zea mays subs. mays). Potatoes arrived in the United States ...

  Citation × Citation Citation Abstract Copy Title: Seasonal Occurrence and Abundance of Insect Pests and Natural Enemies in the Columbia Basin Author: Klein, Matthew L. Potato (Solanum tuberosum L.) is the fourth largest food crop in the world following rice (Oryza sativa L.), wheat (Triticum spp.), and maize (Zea mays subs. mays). Potatoes arrived in the United States in the early 1600s and over the following centuries, the crop was subsequently cultivated across the country and world. The highest productive potato region in North America is in the Columbia Basin of Eastern Oregon and Washington. The Columbia Basin (OR and WA) and Idaho account for close to 60% of United States production of both fresh and processed potatoes. This thesis, entitled “Seasonal occurrence and abundance of insect pests and natural enemies in the Columbia Basin” is divided in three chapters, the first being an overarching introduction that ties together the common themes of the following research based chapters. In the second chapter we document a field experiment we conducted on the potato psyllid, Bactericera cockerelli Sulc (Hemiptera: Triozidae), a key potato pest that has the ability to vector the plant pathogenic bacterium Candidatus Liberibacter solanacearum (Lso). In this study, we also collected data on insect predators (natural enemies), specifically the taxa: Geocoris spp., Nabis spp., and Orius spp. The literature indicates that the potato psyllid has a close affinity for solanaceous crops and weeds and our hypothesis was that the presence of potato psyllids in crops such as maize or wheat was due to the presence of volunteer potatoes. In the region, potatoes are in rotation with both maize and wheat. Thus, the objectives of this study were to (1) evaluate the role of potato, maize, and wheat, as well as maize planted with volunteer potatoes and wheat planted with volunteer potatoes on the population dynamics of potato psyllids and natural enemies and (2) compare two sampling techniques: sticky traps and inverted leaf blowers, for monitoring potato psyllids adults and natural enemies. Data collected in this study suggested that potato psyllids have an affinity for potato crops even in the presence of a diverse crop landscape and also that differences may occur between trapping methods. Potato psyllids were rarely found in maize and wheat and were more likely to be found in plots containing volunteer potatoes. Little association was found between crop treatment and natural enemy presence. However, there were differences in potato psyllid and natural enemy captures when using both collection methods and they were present in all crop treatments tested. These results have implications for potato psyllid management as well as utilizing natural enemies for suppression of key pests. The third chapter was designed to provide regional information on aphids (Hemiptera: Aphididae) in the Columbia Basin (Umatilla and Morrow Counties) and Eastern Oregon (Union and Baker Counties). The potato aphid (PA) Macrosiphum euphorbiae Thomas, the green peach aphid (GPA) Myzus persicae Sulzer, and various other aphids (OA) were the focus of this study. The objectives were to (1) determine spatial, yearly, and weekly trends in GPA, PA, and OA populations in the Columbia Basin and (2) determine abiotic environmental variables that could potentially have a significant impact on population levels in the following growing season. In our analysis, we observed that aphid populations were distributed heterogeneously both spatially and temporally with large differences in aphid numbers between species, year, and trapping locations. We also found that aphids were influenced by previous season dew point, previous season temperature, and to a lesser extent by elevation. This data supports the conclusion that aphid populations respond in a complex fashion to environmental variables and that managing aphid populations requires the collection of ample data. These results indicate the difficulty in managing aphid pests. Title: Seasonal Occurrence and Abundance of Insect Pests and Natural Enemies in the Columbia Basin Author: Klein, Matthew L. Potato (Solanum tuberosum L.) is the fourth largest food crop in the world following rice (Oryza sativa L.), wheat (Triticum spp.), and maize (Zea mays subs. mays). Potatoes arrived in the United States in the early 1600s and over the following centuries, the crop was subsequently cultivated across the country and world. The highest productive potato region in North America is in the Columbia Basin of Eastern Oregon and Washington. The Columbia Basin (OR and WA) and Idaho account for close to 60% of United States production of both fresh and processed potatoes. This thesis, entitled “Seasonal occurrence and abundance of insect pests and natural enemies in the Columbia Basin” is divided in three chapters, the first being an overarching introduction that ties together the common themes of the following research based chapters. In the second chapter we document a field experiment we conducted on the potato psyllid, Bactericera cockerelli Sulc (Hemiptera: Triozidae), a key potato pest that has the ability to vector the plant pathogenic bacterium Candidatus Liberibacter solanacearum (Lso). In this study, we also collected data on insect predators (natural enemies), specifically the taxa: Geocoris spp., Nabis spp., and Orius spp. The literature indicates that the potato psyllid has a close affinity for solanaceous crops and weeds and our hypothesis was that the presence of potato psyllids in crops such as maize or wheat was due to the presence of volunteer potatoes. In the region, potatoes are in rotation with both maize and wheat. Thus, the objectives of this study were to (1) evaluate the role of potato, maize, and wheat, as well as maize planted with volunteer potatoes and wheat planted with volunteer potatoes on the population dynamics of potato psyllids and natural enemies and (2) compare two sampling techniques: sticky traps and inverted leaf blowers, for monitoring potato psyllids adults and natural enemies. Data collected in this study suggested that potato psyllids have an affinity for potato crops even in the presence of a diverse crop landscape and also that differences may occur between trapping methods. Potato psyllids were rarely found in maize and wheat and were more likely to be found in plots containing volunteer potatoes. Little association was found between crop treatment and natural enemy presence. However, there were differences in potato psyllid and natural enemy captures when using both collection methods and they were present in all crop treatments tested. These results have implications for potato psyllid management as well as utilizing natural enemies for suppression of key pests. The third chapter was designed to provide regional information on aphids (Hemiptera: Aphididae) in the Columbia Basin (Umatilla and Morrow Counties) and Eastern Oregon (Union and Baker Counties). The potato aphid (PA) Macrosiphum euphorbiae Thomas, the green peach aphid (GPA) Myzus persicae Sulzer, and various other aphids (OA) were the focus of this study. The objectives were to (1) determine spatial, yearly, and weekly trends in GPA, PA, and OA populations in the Columbia Basin and (2) determine abiotic environmental variables that could potentially have a significant impact on population levels in the following growing season. In our analysis, we observed that aphid populations were distributed heterogeneously both spatially and temporally with large differences in aphid numbers between species, year, and trapping locations. We also found that aphids were influenced by previous season dew point, previous season temperature, and to a lesser extent by elevation. This data supports the conclusion that aphid populations respond in a complex fashion to environmental variables and that managing aphid populations requires the collection of ample data. These results indicate the difficulty in managing aphid pests. Close

• 46. [Article] Web based visualization of large climate data sets

  To the best of our knowledge, one or more authors of this paper were federal employees when contributing to this work. This is the publisher’s final pdf. The published article is copyrighted by Elsevier ...

  Citation × Citation Citation Abstract Copy Title: Web based visualization of large climate data sets Author: Hostetler, S. W., Alder, J. R. To the best of our knowledge, one or more authors of this paper were federal employees when contributing to this work. This is the publisher’s final pdf. The published article is copyrighted by Elsevier and can be found at: http://www.sciencedirect.com/science/journal/13648152 Title: Web based visualization of large climate data sets Author: Hostetler, S. W., Alder, J. R. To the best of our knowledge, one or more authors of this paper were federal employees when contributing to this work. This is the publisher’s final pdf. The published article is copyrighted by Elsevier and can be found at: http://www.sciencedirect.com/science/journal/13648152 Close

• 47. [Article] Tidal wetland prioritization for the Nehalem River estuary

  Prepared for the U.S. Fish and Wildlife Service Oregon Coastal Program - Newport Field Office.

  Citation × Citation Citation Abstract Copy Title: Tidal wetland prioritization for the Nehalem River estuary Author: Brophy, Laura, So, Khemarith Prepared for the U.S. Fish and Wildlife Service Oregon Coastal Program - Newport Field Office. Title: Tidal wetland prioritization for the Nehalem River estuary Author: Brophy, Laura, So, Khemarith Prepared for the U.S. Fish and Wildlife Service Oregon Coastal Program - Newport Field Office. Close

• 48. [Article] The biology and behavior of the alkali bee Nomia melanderi Cockerell (Hymnoptera:Apoidea)

  Nomia melanderi Cockerell is one of the most efficient pollinators of alfalfa in Eastern Oregon. Emergence begins in June, usually reaches its peak in early July, and may continue into early August. Male ...

  Citation × Citation Citation Abstract Copy Title: The biology and behavior of the alkali bee Nomia melanderi Cockerell (Hymnoptera:Apoidea) Author: Hackwell, Glenn Alfred Nomia melanderi Cockerell is one of the most efficient pollinators of alfalfa in Eastern Oregon. Emergence begins in June, usually reaches its peak in early July, and may continue into early August. Male emergence precedes female emergence by four or five days. For the first few weeks of this time, the males spend the morning hours patrolling the nesting area. As each new female bee emerges, many males attempt to mate with her , but most contacts are unsuccessful. Soil temperature and moisture are the prime factors influencing emergence. After mating has been accomplished, the female bee forages in the field and returns to the bee bed in the afternoon to begin nest construction. The male also spends the afternoon in the field, returning to spend the night in clusters on plants on, or in the vicinity of the bee bed. Some crawl under the loose soil crust, paper, sticks, rocks, or enter burrows for the night. The female, after digging herself under the soil surface, spends the nest two or three days roughing out cells. On the third, fourth or fifth day she begins to collect pollen. She usually forages on blossoms close to the nest, tripping about 96 percent of those visited. The female gradually increases her foraging range, moving progressively further from the nest as she ages. The time required to complete each pollen collecting trip varies considerably, but averages close to 35 minutes. It takes from seven to 11 trips to complete one pollen ball and this may require from 5 1/2 to 9 hours. The female trips the alfalfa blossom by forcing its head against the standard petal while its legs are braced against the wing petals. Mortality is evidenced by an abrupt decline in the number of working females. Eggs of Nomia melanderi require from 2 1/2 to 3 days to hatch. The larva passes through five instars. The fifth instar defecates after all the pollen has been consumed, and transforms into the prepupa, which passes through the winter. The following spring the prepupa transforms into the pupa which shortly develops into the mature adult. The alkali bee uses major and minor landmarks for orientation. Larger landmarks such as haystacks, trees, fences, roads , and ditches are used to locate the bee bed. Then smaller markers such as soil clods, sticks, etc. are used to locate the individual burrow opening. Preliminary studies suggest that the alkali bee is able to distinguish among yellow, green, blue, white and gray colors. Temperature is usually the limiting factor in the initiation of morning activity, whereas light intensity appears to determine the time of flight cessation in the evening. Title: The biology and behavior of the alkali bee Nomia melanderi Cockerell (Hymnoptera:Apoidea) Author: Hackwell, Glenn Alfred Nomia melanderi Cockerell is one of the most efficient pollinators of alfalfa in Eastern Oregon. Emergence begins in June, usually reaches its peak in early July, and may continue into early August. Male emergence precedes female emergence by four or five days. For the first few weeks of this time, the males spend the morning hours patrolling the nesting area. As each new female bee emerges, many males attempt to mate with her , but most contacts are unsuccessful. Soil temperature and moisture are the prime factors influencing emergence. After mating has been accomplished, the female bee forages in the field and returns to the bee bed in the afternoon to begin nest construction. The male also spends the afternoon in the field, returning to spend the night in clusters on plants on, or in the vicinity of the bee bed. Some crawl under the loose soil crust, paper, sticks, rocks, or enter burrows for the night. The female, after digging herself under the soil surface, spends the nest two or three days roughing out cells. On the third, fourth or fifth day she begins to collect pollen. She usually forages on blossoms close to the nest, tripping about 96 percent of those visited. The female gradually increases her foraging range, moving progressively further from the nest as she ages. The time required to complete each pollen collecting trip varies considerably, but averages close to 35 minutes. It takes from seven to 11 trips to complete one pollen ball and this may require from 5 1/2 to 9 hours. The female trips the alfalfa blossom by forcing its head against the standard petal while its legs are braced against the wing petals. Mortality is evidenced by an abrupt decline in the number of working females. Eggs of Nomia melanderi require from 2 1/2 to 3 days to hatch. The larva passes through five instars. The fifth instar defecates after all the pollen has been consumed, and transforms into the prepupa, which passes through the winter. The following spring the prepupa transforms into the pupa which shortly develops into the mature adult. The alkali bee uses major and minor landmarks for orientation. Larger landmarks such as haystacks, trees, fences, roads , and ditches are used to locate the bee bed. Then smaller markers such as soil clods, sticks, etc. are used to locate the individual burrow opening. Preliminary studies suggest that the alkali bee is able to distinguish among yellow, green, blue, white and gray colors. Temperature is usually the limiting factor in the initiation of morning activity, whereas light intensity appears to determine the time of flight cessation in the evening. Close

• 49. [Article] Soil erosion assessment in the Republic of Cape Verde, West Africa, using a geographic information system

  Soil erosion is a natural physical process. However it can become a detrimental force when factors such as infertile soils, steep topography and poor farming practices are combined. An important initial ...

  Citation × Citation Citation Abstract Copy Title: Soil erosion assessment in the Republic of Cape Verde, West Africa, using a geographic information system Author: Gomez, Sharon N. Soil erosion is a natural physical process. However it can become a detrimental force when factors such as infertile soils, steep topography and poor farming practices are combined. An important initial aspect of resource planning and/or soil conservation involves locating areas where such potentially hazardous combinations occur in the field. This study proposes the development of a soil erosion hazard map for a watershed in the Cape Verde islands, West Africa. The Cape Verde archipelago is composed of volcanic islands that constitute the western extreme of the Sahel. They provide classic examples of those areas where combinations of certain environmental factors result in cases of severe sheet, nil and gully erosion. A range of computer software and theoretical modelling was used to develop a soil erosion hazard map for a 110 sq.km. watershed on the main island of Santiago. The programs included a computer cartography programme (Aut0CAD), a Digital Elevation Modelling program (SURFER) and a Geographic Information System - GIS (IDRISI). The research provided a study of the independent variables that impact soil erosion and their interactions. It also illustrated several concepts of automated environmental modelling and mapping: for instance data entry; vector-raster, raster-vector conversions; data analysis using a GIS and data output. The final map indicated that most of the watershed was susceptible to low-moderate risk erosion. And the rest of the land posed a moderate-high or severe risk erosion. More importantly, the map will allow planners to gain an insight into the location of areas that require attention for conservation measures in the watershed. Title: Soil erosion assessment in the Republic of Cape Verde, West Africa, using a geographic information system Author: Gomez, Sharon N. Soil erosion is a natural physical process. However it can become a detrimental force when factors such as infertile soils, steep topography and poor farming practices are combined. An important initial aspect of resource planning and/or soil conservation involves locating areas where such potentially hazardous combinations occur in the field. This study proposes the development of a soil erosion hazard map for a watershed in the Cape Verde islands, West Africa. The Cape Verde archipelago is composed of volcanic islands that constitute the western extreme of the Sahel. They provide classic examples of those areas where combinations of certain environmental factors result in cases of severe sheet, nil and gully erosion. A range of computer software and theoretical modelling was used to develop a soil erosion hazard map for a 110 sq.km. watershed on the main island of Santiago. The programs included a computer cartography programme (Aut0CAD), a Digital Elevation Modelling program (SURFER) and a Geographic Information System - GIS (IDRISI). The research provided a study of the independent variables that impact soil erosion and their interactions. It also illustrated several concepts of automated environmental modelling and mapping: for instance data entry; vector-raster, raster-vector conversions; data analysis using a GIS and data output. The final map indicated that most of the watershed was susceptible to low-moderate risk erosion. And the rest of the land posed a moderate-high or severe risk erosion. More importantly, the map will allow planners to gain an insight into the location of areas that require attention for conservation measures in the watershed. Close

• 50. [Article] Ceratomyxa shasta-related concerns for reintroduced anadromous salmonids into the Upper Klamath Basin, CA-OR, USA

  The myxozoan parasite of salmonids, Ceratomyxa shasta, is established throughout the Klamath River, CA-OR, with high parasite densities below the series of dams and above the dams (upper basin) in the ...

  Citation × Citation Citation Abstract Copy Title: Ceratomyxa shasta-related concerns for reintroduced anadromous salmonids into the Upper Klamath Basin, CA-OR, USA Author: Hurst, Charlene N. The myxozoan parasite of salmonids, Ceratomyxa shasta, is established throughout the Klamath River, CA-OR, with high parasite densities below the series of dams and above the dams (upper basin) in the northernmost tributary, the Williamson River (WMR). Two objectives were designed to address concerns about C. shasta effects on reintroduced anadromous salmonids in the upper basin. The first objective investigated parasite dynamics in the WMR and the second determined the virulence of parasite genotypes in allopatric and sympatric salmonid strains. Parasite density, distribution and genotype composition were assessed from water samples collected throughout the WMR and its tributaries. High parasite densities occurred in two sections of the WMR and the genotype associated with stocking of an allopatric strain of rainbow trout predominated. In laboratory cross-infection experiments, the stage of the parasite infective for fish of genotypes I and II (biotype IIR and IIC) were used in three separate trials to challenge four strains of salmonid; sympatric strains of Chinook (Oncorhynchus tswytshcha) and coho (O. kisutch) salmon and allopatric strains of Chinook salmon and rainbow trout (O. mykiss). Genotype I caused mortality in both Chinook strains, while mortality in the allopatric Chinook strain also occurred with IIR. Mortality of rainbow trout resulted from biotypes IIR and IIC, but mortality in coho only occurred with exposure to IIC. Thus, the parasite genotypes/biotypes that cause mortality in native Klamath River fish (i.e. I and IIC) were not present in the upper basin, but could become established and amplify as the stocking of allopatric rainbow trout illustrates. Title: Ceratomyxa shasta-related concerns for reintroduced anadromous salmonids into the Upper Klamath Basin, CA-OR, USA Author: Hurst, Charlene N. The myxozoan parasite of salmonids, Ceratomyxa shasta, is established throughout the Klamath River, CA-OR, with high parasite densities below the series of dams and above the dams (upper basin) in the northernmost tributary, the Williamson River (WMR). Two objectives were designed to address concerns about C. shasta effects on reintroduced anadromous salmonids in the upper basin. The first objective investigated parasite dynamics in the WMR and the second determined the virulence of parasite genotypes in allopatric and sympatric salmonid strains. Parasite density, distribution and genotype composition were assessed from water samples collected throughout the WMR and its tributaries. High parasite densities occurred in two sections of the WMR and the genotype associated with stocking of an allopatric strain of rainbow trout predominated. In laboratory cross-infection experiments, the stage of the parasite infective for fish of genotypes I and II (biotype IIR and IIC) were used in three separate trials to challenge four strains of salmonid; sympatric strains of Chinook (Oncorhynchus tswytshcha) and coho (O. kisutch) salmon and allopatric strains of Chinook salmon and rainbow trout (O. mykiss). Genotype I caused mortality in both Chinook strains, while mortality in the allopatric Chinook strain also occurred with IIR. Mortality of rainbow trout resulted from biotypes IIR and IIC, but mortality in coho only occurred with exposure to IIC. Thus, the parasite genotypes/biotypes that cause mortality in native Klamath River fish (i.e. I and IIC) were not present in the upper basin, but could become established and amplify as the stocking of allopatric rainbow trout illustrates. Close