Oregon Research Papers - Academia.edu (original) (raw)

that run throughout the book. For example, many of the authors consider whether arbitrary sound-object associations can account for word learning, or whether children must be sensitive to person-object relations and communicative intention. A further debate that arises in many chapters concerns children's reliance on perceptual cues versus their formation of conceptual knowledge. The consideration of specific issues and more general theoreti-cal questions is well integrated throughout the 19 chapters. Consequently, this volume represents essential reading for those studying word learning.

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- Psychology, Cognitive Science, Bioethics Reproductive Technology, Oregon

We examined the effects of wild ungulates (deer and elk) and domestic sheep browsing on the growth, structure, and reproductive effort of two common willow species, Salix boothii and S. geyeriana, in a montane northeast Oregon riparian zone. With the use of exclosures, large herbivore effects on willows were studied in an area browsed by native mammals only and an adjacent area in which domestic sheep also lightly grazed during summer months. Growth variables were repeatedly measured on individual plants over a 5-year period to understand physiognomic and flowering responses of native willows to different levels of browsing pressure. At the beginning of the study, all willows were intensely browsed but were significantly taller in the area browsed only by native mammals than in the area also grazed by sheep (69 versus 51 cm, respectively). Willows inside exclosures responded with pronounced increases in height, crown area, and basal stem diameters while the stature of browsed plants outside exclosures stayed constant or declined. In the area browsed by both sheep and wild herbivores, the size of browsed plants remained at pre-treatment levels (<60 cm in height) for the duration of the study. There was no significant difference in growth rates of enclosed willows, indicating that current herbivory was the primary cause of growth retardation in the study area. Foliar area was strongly correlated with basal stem numbers for enclosed plants but much less so for browsed plants. Willows inside exclosures had more than twice as much foliar area per stem. Stem diameters were a positive function of crown area: stemnumber ratios, suggesting lower photosynthetic potential was correlated with diminished radial growth among browsed plants. No flowering was observed until 2 years after exclusion when plants inside all exclosures and browsed willows in the wild ungulate area responded with a large pulse in flowering. Browsed plants in the sheep + wild ungulate area did not flower. The number of catkins produced per plant was significantly associated with willow height and plants <70 cm in height did not flower, thus suggesting a size threshold for reproduction in these species. Our results suggest that even relatively light levels of domestic livestock grazing, when coupled with intense wild ungulate browsing, can strongly affect plant structure and limit reproduction of riparian willows.

- by Boone Kauffman
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- Ecology, Population Dynamics, Growth, Oecologia

An individual-based model of nesting smallmouth bass, Micropterus dolomieu, is used to predict the effects of water level fluctuations on reproductive success. The model simulates daily nest site selection, spawning, nest guarding, and development and survival of eggs, embryos, and larvae until dispersal. The model was configured for Brownlee Reservoir, Idaho-Oregon. Each reservoir bank is represented as a rectangular grid of cells, with each cell characterized by an assigned slope, substrate, and elevation, and by a water depth that varied daily. Nest site (cell) selection is determined from a habitat suitability index (HSI) based on substrate, slope, and depth. Development of young is temperature-dependent. Mortality of young occurs via attrition, abandonment by the guarding male, and probabilistic whole-nest catastrophe. Simulations were performed that used observed data for 1991 to 1996. Model predicted nest habitat selection and egg-to-dispersal survival rates were similar to observed values. Additional model simulations showed that: (1) nest habitat selection was best predicted when depth, slope, and substrate were considered together rather than singly, (2) egg-todispersal survival was related to the magnitude of water level fluctuations during the peak spawning period, (3) relating mortality to HSI values resulted in lower survival, while relating growth to HSI values resulted in higher survival, and (4) spawning habitat is not limiting in Brownlee Reservoir. Suggestions for future monitoring of reservoir-based smallmouth bass populations are discussed.

- by James Chandler
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- Zoology, Ecology, Habitat Selection, Reproductive Success

Beginning in 1993, 12 institutions and individuals and The PawPaw Foundation (PPF) embarked on a joint venture to evaluate commercially-available, named pawpaw (Asimina triloba) varieties and PPF's advanced selections within and outside of the pawpaw's native range. Each Pawpaw Regional Variety Trial (PRVT) planting, consists of about 300 trees, with five to eight replications (blocks) of 28 grafted scion varieties per block in a randomized complete block design (10 named varieties and 18 clones selected in the PPF orchards at the University of Maryland Experiment Stations at Queenstown and Keedysville, Md.). Variables being examined in the trial include climatic effect, culture, pests, growth, fl owering, yield, and fruit characteristics. In 1995, PRVT plantings were established in Kentucky (Princeton, Ky.), Louisiana, North Carolina, Oregon, and South Carolina. In 1998, a second planting was established in Kentucky (Frankfort, Ky.). In 1999, PRVT plantings were established...

- by Desmond Layne
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- South Carolina, North Carolina, Data Collection, Fruit Production

To test the ability of an automated telephone outreach intervention to reduce acute healthcare utilization and improve quality of life among adult asthma patients in a large managed care organization. Randomized clinical trial. Patients with persistent asthma were randomly assigned to telephone outreach (automated = 3389, live caller = 192) or usual care (n = 3367). Intervention participants received 3 outreach calls over a 10-month period. The intervention provided brief, supportive information and flagged individuals with poor asthma control for follow-up by a provider. A survey was mailed to 792 intervention participants and 236 providers after the intervention. Additional feedback was obtained as part of the final intervention contact. The intent-to-treat analysis found no significant differences between the intervention and usual-care groups for medication use, healthcare utilization, asthma control, or quality of life. Post hoc analyses found that, compared with the control gr...

- by David Mosen
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- Management, Program Evaluation, Asthma, Social Support

Took!the standard guided plant tour which _s offered routinely to the i;ubllc

- by Dana Bjornson
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- Engineering, Computer Aided Design, Energy Conservation, Energy Consumption

It has been argued that the traditional regulatory approach of the Endangered Species Act, based on land-use restrictions, has failed to protect endangered species on private land. In response, there has been a call for the use of incentives to complement this regulatory approach. This paper examines the potential of incentives programs to elicit conservationoriented management choices from landowners. Data obtained from a survey of nonindustrial private forest owners in Oregon and Washington is used to examine the effectiveness of various incentives. The results indicate that incentives, in particular compensation and assurances, can be effective in increasing the conservation effort provided by landowners. The results also suggest that conservation policy for private lands could be improved by relying on a combination of incentives, including financial incentives and assurances, rather than exclusively on the threat of regulation.

- by Christian Langpap
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- Energy Economics, Ecological Economics, Endangered Species, Applied Economics

ENHANCEMENT OF HEAT AND MASS TRANSFER IN MECHANICALLY-CONSTRAINED ULTRA-THIN FILMS SECTION 1.0-INTRODUCTION AND BACKGROUND Oregon State University (OSU) and the Pacific Northwest National Laboratory (PNNL) were funded by the U.S. Department of Energy to conduct research focused on resolving the key technical issues that limited the deployment of efficient and extremely compact microtechnology based heat actuated absorption heat pumps and gas absorbers. Success in demonstrating these technologies will reduce the main barriers to the deployment of a technology that can significantly reduce energy consumption in the building, automotive and industrial sectors while providing a technology that can improve our ability to sequester CO 2. The

- by James Liburdy
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- Mass Transfer, Energy Consumption, Stability, Heat and Mass Transfer

Population declines due to chytridiomycosis among frogs belonging to the Amerana (Rana boylii) species group from western North America have been particularly severe. Norepinephrine-stimulated skin secretions from the Oregon spotted frog Rana pretiosa Baird and Girard, 1853 were collected from individuals that had been previously infected with the causative agent Batrachochytrium dendrobatidis but had proved resistant to developing chytridiomycosis. These secretions contained a more diverse array of antimicrobial peptides than found in other species from the Amerana group and 14 peptides were isolated in pure form. Determination of their primary structures identified the peptides as esculentin-2PRa and -2PRb; ranatuerin-2PRa, -2PRb, -2PRc, -2PRd, and -2PRe; brevinin-1PRa, -1PRb, -1PRc, and -1PRd; and temporin-PRa, -PRb, and -PRc. The strongly cationic ranatuerin-2PRd and the esculentin-2 peptides, which have not been identified in the secretions of other Amerana species except for the closely related R. luteiventris, showed the highest growth inhibitory potency against microorganisms. The strongly hydrophobic brevinin-1PRd was the most cytotoxic to erythrocytes. Although no clear correlation exists between production of dermal antimicrobial peptides by a species and its resistance to fatal chytridiomycosis, the diversity of these peptides in R. pretiosa may be pivotal in defending the species against environmental pathogens such as B. dendrobatidis.

- by Eman Ahmed
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- Immunology, Innate immunity, Western North America, Skin

Objectives-School tobacco use policies are part of a comprehensive strategy for preventing or reducing adolescent cigarette smoking. This study examines the relationship between perceived tobacco policy enforcement at the school level and... more

- by Sharon Lipperman-kreda
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- Tobacco, Preventive medicine, Risk Taking, Health Policy

There have been many attempts to classify geographic areas into zones of similar characteristics. Recent focus has been on ecoregions. We examined how well the boundaries of the most commonly used ecoregion classi®cations for the US matched the boundaries of existing vegetation cover mapped at three levels of classi®cation, ®ne, mid-and coarse scale. We analyzed ecoregions in Idaho, Oregon and Washington. The results were similar among the two ecoregion classi®cations. For both ecoregion delineations and all three vegetation classi®cations, the patterns of existing vegetation did not correspond well with the patterns of ecoregions. Most vegetation types had a small proportion of their total area in a given ecoregion. There was also no dominance by one or more vegetation types in any ecoregion and contrary to our hypothesis, the level of congruence of vegetation patterns with ecoregion boundaries decreased as the level of classi®cation became more general. The implications of these ®...

- by Troy Merrill
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- Biological Sciences, Environmental Sciences, Biological Conservation, Oregon

Despite its grounding in a specific and peculiar set of facts, the strict scrutiny mandate of Wisconsin v. Yoder (decided in 1972) has changed the constitutional landscape of custody cases - and it has done so in a way that is unsound both as a matter of law and policy. Following Yoder, most courts require a showing of harm to the child, or a substantial threat of harm to the child, before placing any restrictions on exposure to a parent's religious beliefs and practices. This harm standard leaves children in an untenable position when parents compete for "spiritual custody," for the law can protect them only when the risk of harm is already substantial. Indeed, the bar is set so high that few courts have found circumstances that satisfy the harm standard. In this essay, I argue that a strict scrutiny standard has no place in spiritual custody cases. It is hardly consistent with the basic principle that the custody court's paramount consideration is the best intere...

- by Jeffrey Shulman
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- Sociology, Constitutional Law, Family Law, Law and Religion
- by Jennifer Swenson and +1
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- Forest Ecology And Management, Environmental Design, Quantitative analysis, Biological Sciences

Interest in the contributions to biological diversity of old-growth forests has increased in many regions of the world. In the Pacific Northwest of the United States, concern for the contributions has lead to proposals to extend the rotation between timber harvests from the conventional 40-80 years to 150 years and longer. However, the implications of such a change for Ž both development of old-growth structure and timber production are unknown. We examined long-term records up to 82 . Ž . years from permanent plots established in 20 stands of Pseudotsuga menziesii Mirb. Franco in western Oregon and Washington that are approaching these proposed rotation ages. Similarity to old-growth structure was assessed by comparing the observed values of four structural variables to published mean values for young and old-growth forest. The assessment of similarity to old-growth structure was limited to characteristics of the live forest stand, due to the lack of measurements of snags and downed logs at initiation of the permanent plots. Timber production was assessed by examining trends in mean Ž . annual increment MAI of cubic volume. Development towards old-growth structure was rapid up to about age 80 years, and gradual thereafter. About half of the transition from young to old-growth forest structure occurred by age 100 years. Stands least similar to old-growth in early observations had relatively high tree densities and relatively small trees of uniform size. In later observations, stands most similar to old-growth structure were those with higher densities of large Ž . ) 100 cm DBH P. menziesii. In general, MAI declined gradually, averaging about 0.3% per year. Thus, longer rotations may not result in large declines of timber growth while providing for forest structure similar to old-growth. Early control of tree density may serve to hasten development of old-growth structure. Our approach to understanding the development of old-growth forest structure could be applied to long-term plot data from forests in other regions, as long as there is adequate information on old-growth and other forest stages. q 1998 Elsevier Science B.V.

by in situ X-ray observations based on the same pressure scale in the previous study . The overpressure was calculated using these boundaries. We observed the pressure to drop during the transformation by 1-2 GPa, but this would not affect the transformation rate significantly because the overpressure is very large in the present study. This has been confirmed in the post-spinel transformation 7 .

- by Stephanie Connon
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- Pharmacology, Biochemistry, Bioinformatics, Evolutionary Biology

Historically, the upper Willamette River valley in western Oregon was characterized by seasonal floods and large expansions of its stream network. During the past century, human activities have altered or eliminated many intermittent stream and floodplain habitats in the valley. As a result, the remaining intermittent streams and ditches, referred to as watercourses, may still provide habitat that is critical for native fish. Our objectives were to determine (1) fish presence, (2) the spatial gradients of fish distribution (including species identity, native versus nonnative status, and numbers), (3) fish use of the intermittent streams as spawning and nursery habitats, and (4) the main factors that influence the numbers of fish and fish species. In the winter and spring of 2002-2003, we examined the distributions of fish species in five subbasins within the Willamette River valley. The sampling sites were in intermittent watercourses that drained grass seedproducing fields. We collected water samples and sampled fish from December to May with minnow traps and an electrofishing unit and collected data on the standard fish habitat variables at all sites in spring. Thirteen fish species were found and only three of them were exotic. The presence of recently hatched and juvenile fish shows that intermittent watercourses offer conditions suitable for spawning and juvenile rearing. The two watershed-scale variables with the most influence on fish species richness were the percentage of the watershed covered by forest and the distance to perennial water, the first of which had a direct relationship to species diversity and the second an inverse relationship. In turn, fish abundance had a negative, albeit modest, relationship with the distance to perennial water. Among local-scale variables, water velocity and conductivity were inversely related to species richness and fish numbers. Our results highlight the relevance of intermittent agricultural watercourses for native fish species in the Willamette River valley and call for the promotion of agricultural conservation practices that benefit farmers while maintaining aquatic biodiversity in floodplain habitats.

- by Judith Li
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- Seasonality, Species Diversity, Fisheries Sciences, Fish habitat

The subspecies composition of migratory sandhill cranes (Grus canadensis) which stage and winter along the Lower Columbia River in northwest Oregon and southwest Washington is uncertain, but may include all 3 using the Pacific Flyway: lesser (G. c. canadensis), Canadian (G. c. rowani), and greater (G. c. tabida). However, the status of rowani has been debated. During 2001-02, we captured and marked 8 cranes using a noose line trapping technique, and attached Platform Transmitter Terminals (PTTs) to 6 to ascertain locations of their breeding areas, migration corridors and winter sites. Morphometric data were collected for subspecies determination. From measurements and their summer distribution, we conclude that they are likely the intermediate rowani form. Because of their limited numbers, distinct coastal migration path, and habitat issues at breeding, staging, and wintering areas, we recommend that conservation efforts be increased and that they be managed as a unique population. ...

- by Gary L Ivey
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- Environmental Education, Conservation Biology, Biodiversity, California

Physicians are currently presented with very difficult ethical issues regarding who receives what level of medical care and for how long. A meaningful response to these perplexing issues necessitates a collaboration of doctors with others steeped in religious and ethical traditions. This paper addresses the complicated issue of the rationing of health care, and this issue is then addressed by responses from representatives of the religious community. This symposium took place at the New York Hospital--Cornell Medical Center in March 1991.

- by Joseph J. Fins
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- Religion, Economics, Decision Making, Poverty

The fluorescence properties of Alexa 488, Oregon Green 488, and Oregon Green 514 (Molecular Probes (Eugene, OR)) are compared when conjugated to biomolecules and as model compounds free in solution. We show that these relatively new, green fluorescence probes are excellent probes for investigation of the thermodynamics of protein-protein and protein-nucleic acid interactions by fluorescence anisotropy. Unlike fluorescein, the emission of these dyes has minimal pH dependence near neutrality and is significantly less susceptible to photobleaching. Steady-state and time-resolved fluorescence anisotropy data are compared for two interacting proteins of different size and for the association of a transcription factor with a DNA oligonucleotide containing a specific binding site. The temperature dependence of the fluorescence lifetimes of the probes is reported, and the effects of molecular size and probe motion on steady-state anisotropy data are discussed. The critical interplay among correlation time, fluorescence lifetime, and the observed steady-state anisotropy is evaluated. Ó

- by Elena Rusinova
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- Thermodynamics, Analytical Chemistry, Kinetics, Fluorescent Dyes and Reagents

Eleven strains of a hitherto undescribed Gram-positive, catalase-negative, facultatively anaerobic rod-shaped bacterium from human sources and medical care products were characterized by phenotypic and molecular taxonomic methods. The phenotypic properties of the bacterium were consistent with its assignment to the genus Lactobacillus but it was readily distinguished from all currently described species of this genus by its biochemical characteristics and by SDS-PAGE analysis of its cellular proteins. Comparative 16s rRNA gene sequence analysis demonstrated that the unknown bacterium was a member of rRNA group I Lactobacillus which includes Lactobacillus delbrueckii, the type species of the genus, and close relatives. Lactobacillus gasseri and Lactobacillus johnsonii were the nearest phylogenetic relatives of the unknown bacterium, but 165 rRNA sequence divergence values of ~4 % clearly showed that it represents a distinct species. Based on both phylogenetic and phenotypic evidence, it is proposed that the unknown bacterium should be classified in the genus Lactobacillus, as Lactobacillus hers sp. nov. The type strain of Lactobacillus hers is CCUG 28746T.

- by Enevold Falsen
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- Microbiology, Colombia, Medical Microbiology, Applied microbiology

Oregon has over 300 ghost towns. Many of these are only names on maps or a a scattering of abandoned and dilapidated buildings. This paper briefly explores the history of some of the better know towns in an effort to preserve the story of... more

- by Rick Hamell
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- History, Ghost Towns, Oregon Archaeology, Oregon

Human perception of riverscapes with and without large wood (LW) has been investigated with a photo-questionnaire submitted to 2250 students in ten countries, capturing reactions to 20 pictures in terms of naturalness, danger, aesthetics and need for improvement. Principal component analysis performed on average scores per country per item showed that the primary discriminating factors are human modification, turbulence and extent of water shown in the scenes. Wood discriminated the perception of student groups, but other factors are also critical. Features associated with human activity (channel deepening and straightening, rip-rapping) were perceived to be less aesthetically pleasing than wood. Perception of the most dangerous riverscapes is not specifically affected by wood, but by turbulent flows and wide rivers. The presence of wood clearly discriminated the need for human intervention. Perceptions differed among countries, reflecting different cultural contexts. Students from Germany, Sweden and Oregon perceived LW more positively as a natural and wild component of watercourses. These perceptions are linked to positive attitudes towards natural riverscapes. Other students, such as those from China, Russia or India, perceived rivers with wood as needing regulation and maintenance. Whatever the socio-cultural context, large wood elicits an emotional influence on how one perceives riverscapes. key words in-channel wood large woody debris public perception riverscape evaluation channel improvement naturalness cross-cultural comparison

Background: Debates over legalisation of physician-assisted suicide (PAS) or euthanasia often warn of a ''slippery slope'', predicting abuse of people in vulnerable groups. To assess this concern, the authors examined data from Oregon and the Netherlands, the two principal jurisdictions in which physician-assisted dying is legal and data have been collected over a substantial period. Methods: The data from Oregon (where PAS, now called death under the Oregon Death with Dignity Act, is legal) comprised all annual and cumulative Department of Human Services reports 1998-2006 and three independent studies; the data from the Netherlands (where both PAS and euthanasia are now legal) comprised all four government-commissioned nationwide studies of end-of-life decision making (1990, 1995, 2001 and 2005) and specialised studies. Evidence of any disproportionate impact on 10 groups of potentially vulnerable patients was sought. Results: Rates of assisted dying in Oregon and in the Netherlands showed no evidence of heightened risk for the elderly, women, the uninsured (inapplicable in the Netherlands, where all are insured), people with low educational status, the poor, the physically disabled or chronically ill, minors, people with psychiatric illnesses including depression, or racial or ethnic minorities, compared with background populations. The only group with a heightened risk was people with AIDS. While extralegal cases were not the focus of this study, none have been uncovered in Oregon; among extralegal cases in the Netherlands, there was no evidence of higher rates in vulnerable groups. Conclusions: Where assisted dying is already legal, there is no current evidence for the claim that legalised PAS or euthanasia will have disproportionate impact on patients in vulnerable groups. Those who received physician-assisted dying in the jurisdictions studied appeared to enjoy comparative social, economic, educational, professional and other privileges. ''… no matter how carefully any guidelines are framed, assisted suicide and euthanasia will be practiced through the prism of social inequality and bias that characterizes the delivery of services in all segments of our society, including health care. The practices will pose the greatest risks to those who are poor, elderly, members of a minority group, or without access to good medical care.'' New York State Task Force on Life and the Law, 1994 1 ''… the State has an interest in protecting vulnerable groups-including the poor, the elderly, and disabled persons-from abuse, neglect, and mistakes. The Court of Appeals [Ninth Circuit] dismissed the State's concern that disadvantaged persons might be pressured into physician assisted suicide as ludicrous on its face.…We have recognized, however, the real risk of subtle coercion and undue influence in end of life situations …'' US Supreme Court, joint opinion in Washington v Glucksberg (1997) and Vacco v Quill (1997) 2 ''Euthanasia and assisted suicide are opposed by almost every national medical association and prohibited by the law codes of almost all countries. … If euthanasia or assisted suicide or both are permitted for competent, suffering, terminally ill patients, there may be legal challenges … to extend these practices to others who are not competent, suffering or terminally ill. Such extension is the ''slippery slope'' that many fear.'' Canadian Medical Association, 1998 3 ''Both society in general and the medical profession in particular have important duties to safeguard the value of human life. This duty applies especially to the most vulnerable members of society-the sick, the elderly, the poor, ethnic minorities, and other vulnerable persons. In the long run, such persons might come to be further discounted by society, or even to view themselves as unproductive and burdensome, and on that basis, ''appropriate'' candidates for assistance with suicide.'' ''… the ramifications [of legalization] are too disturbing for the … value our society places on life, especially on the lives of disabled, incompetent, and vulnerable persons.''

- by Bregje Onwuteaka-Philipsen
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- Applied Ethics, Medical Ethics, Euthanasia, Adolescent

suggested that Atlantic sturgeon were likely aggregating to some degree. Total lengths of captured Atlantic sturgeon ranged from 577 to 1,517 mm (mean of 967 mm), suggesting that most fish were juveniles. Limited tag returns and genetic data suggest that fish wintering off North Carolina constitute a mixed stock. Information about their distribution and habitat utilization should benefit fishery managers seeking to reduce bycatch and protect key habitats.

- by Wilson Laney
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- North Carolina, Fishery Management, Habitat Use, Geographic distribution

Gender differences in anxiety were examined in a large sample of adolescents that included 1,079 who had never met criteria for any disorder, 95 who had recovered from an anxiety disorder, and 47 who had a current anxiety disorder. Participants were examined on a wide array of psychosocial measures. There was a preponderance of females among current and recovered anxiety disorder cases, but not among those who had never experienced an anxiety disorder. The female preponderance emerges early in life, and retrospective data indicate that at age 6, females are already twice as likely to have experienced an anxiety disorder than are males. Psychosocial variables that were correlated with both anxiety and gender were identified. Statistically controlling for these variables did not eliminate the gender differences in prevalence or anxiety symptom means.

- by Ian Gotlib
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- Psychology, Abnormal Psychology, Anxiety Disorders, Personality Assessment

We examined variations in the juvenile life history of fall-spawning Chinook salmon, Oncorhynchus tshawytscha, for evidence of change in estuarine residency and migration patterns following the removal of dikes from 145 ha of former salt-marsh habitat in the Salmon River estuary (Oregon). Mark-recapture studies and abundance patterns in the estuary during 2000e2002 describe the following life-history types among Chinook salmon: (1) fry disperse throughout the estuary, and many move into restored tidalmarsh habitats in the early spring soon after emergence; (2) juveniles reside in freshwater for several months, enter the estuary in June or July, and remain for (a) a few weeks or (b) several months before entering the ocean; and (3) juveniles enter the ocean later in the fall after an extended period of rearing upriver and/or in the estuary. The absence of fry migrants in the estuary during spring and early summer in 1975e1977 d a period that precedes restoration of any of the diked marshes d and the extensive use of marsh habitats by fry and fingerlings AprileJuly, 2000e2002 indicate that wetland restoration has increased estuarine rearing opportunities for juvenile Chinook salmon. Year-to-year patterns of estuarine rearing and abundance by juvenile salmon may be influenced by flood and drought conditions that affected adult spawner distribution and over-winter survival of salmon eggs. However, persistent changes in spawner distribution since 1975e1977, including the concentration of hatchery strays in the lower river, may account for the large proportion of fry that now disperse into the estuary soon after emergence in the spring. Although few of these earliest migrants survived to the river mouth, many fry and fingerlings from mid-and upper-basin spawning areas distributed throughout a greater portion of the estuary during the spring and summer and migrated to the ocean over a broader range of sizes and time periods than thirty years ago. The results suggest that wetland recovery has expanded life history variation in the Salmon River population by allowing greater expression of estuarine-resident behaviors.

- by Charles Simenstad
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- Earth Sciences, Life history, Aquaculture, Biological Sciences

Background: School recess before lunch (e.g., reverse recess) has been suggested as a means to improve dietary intake and classroom behavior but limited research explores this school-based policy. This pilot study tests the impact of recess scheduling on dietary intake at school lunch. Methods: A mixed methods approach included assessment of dietary intake assessed by measured plate waste on five non-consecutive days at Madras Elementary School, Madras, Oregon, United States (n = 104 intervention; 157 controls). Subjects included primary school children in grades kindergarten, first and second. Logistic regression was used to test associations between recess timing and dietary intake. Four focus groups involving teachers and staff explored reactions to the intervention. Qualitative data was transcribed verbatim and assessed for key themes. Results: Milk consumption was 1.3 oz greater in the intervention group (5.7 oz vs. 4.4 oz); and 20% more of the intervention participants drank the entire carton of milk (42% vs. 25%, p < 0.0001). Intervention participants were 1.5 times more likely to meet the nutritional guidelines for calcium (≥267 mg, p = 0.01) and fat (≤30% of total energy, p = 0.02). Consumption of entrees, vegetables, and fruits did not differ between groups. Teachers perceived recess before lunch beneficial to classroom behavior and readiness to concentrate following lunch. Conclusions: The recess before lunch intervention yielded increased milk consumption; the nutritional and social benefits observed warrant policy change consideration. Future research should assess the impact of recess before lunch in larger districts.

- by Monica Hunsberger
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- Diet, Community Based Participatory Research, Schools, Child

Poor water quality from hypereutrophic Upper Klamath Lake in south-central Oregon has been suspected of contributing to the recruitment failure of two endangered endemic fish species, the Lost River sucker Deltistes luxatus and the shortnose sucker Chasmistes brevirostris. We used otolith daily increment widths as a proxy for juvenile somatic growth to construct two growth models: (1) a linear mixed-effects (LME) model examining the lifetime effects of lakewide averages of potentially stressful daytime water temperature, pH, and nighttime dissolved oxygen (DO), and (2) a simple linear regression model examining the effects of locally measured water temperature, pH, and daytime DO on growth of fish over 3 d before the fish's capture. Graphical relationships between daily growth and biweekly un-ionized ammonia failed to show a sublethal effect on the growth of suckers captured in areas where un-ionized ammonia surpassed levels lethal to both species. For both species, our LME models indicated that at temperatures greater than approximately 22ЊC, low nighttime DO (less than 4 mg/L for Lost River suckers and less than 1 mg/L for shortnose suckers) caused enough stress to reduce growth, whereas at temperatures less than approximately 22ЊC, any stress from low nighttime DO was not reflected in reduced growth. We attribute the pattern to the species' tolerance of low DO, the short duration of nighttime events, the fish's increased oxygen demand at higher temperatures, and growth compensation due to increased food resources associated with low DO. The combination of low DO and high temperature has also been implicated in adult fish kills in Upper Klamath Lake. Because 34% of the time lakewide August average temperatures exceeded 22ЊC, extended periods of warm temperatures and high primary production could affect the sizes of recruits surviving into fall. Both growth models suggested that shortnose suckers might be more tolerant of poor water quality than Lost River suckers.

- by Jacob Kann
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- Water quality, Growth, Mixed Effects Models, Ph

Total phenolic content (TPC) and total antioxidant capacity (TAC) of four onion varieties (red, white, yellow and sweet) and shallot from selected locations (Washington, Idaho, Oregon, Texas and Georgia) were determined using Fourier transform infrared (FT-IR) spectroscopy (4000-400 cm À1 ). The Folin-Ciocalteu (F-C) assay was used to quantify TPC and three assays were used to determine TAC, including 2,2-diphenyl-picrylhydrazyl (DPPH) assay, Trolox equivalent antioxidant capacity (TEAC) assay and ferric reducing antioxidant power (FRAP) assay. Partial least squares regression (PLSR) with cross-validation (leave-oneout) was conducted on onion and shallot extracts (n = 200) and their corresponding F-C, DPPH, TEAC and FRAP values were employed to obtain four independent calibration models for predicting TPC and TAC for the extracts. Spectra from an extra 19 independent extracts were used as an external validation set for prediction. A correlation of r > 0.95 was obtained between FT-IR predicted and reference values (by F-C, DPPH, TEAC and FRAP assay) with standard errors of calibration (SEC) and standard errors of cross-validation (SECV) less than 2.85, 0.35 and 0.45 lmol Trolox/g FW of extracts for TEAC, FRAP and DPPH assay, respectively; and 0.36 mg gallic acid/g FW of extracts for the F-C assay. In addition, cluster analysis (principal component analysis (PCA)) and discriminant function analysis (DFA) could differentiate varieties of onions and shallot based upon infrared spectral features. Loading plots for the various chemometrics models indicated that hydroxyl and phenolic functional groups were most closely correlated with antioxidant capacity. The use of mid-infrared spectroscopy to predict the total antioxidant capacity of vegetables provides a rapid and precise alternative to traditional wet chemistry analysis.

- by Barbara Rasco
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- Engineering, Principal Component Analysis, Food Chemistry, Multidisciplinary

Chemical contaminants can be introduced into estuarine and marine ecosystems from a variety of sources including wastewater, agriculture and forestry practices, point and non-point discharges, runoff from industrial, municipal, and urban lands, accidental spills, and atmospheric deposition. The diversity of potential sources contributes to the likelihood of contaminated marine waters and sediments and increases the probability of uptake by marine organisms. Despite widespread recognition of direct and indirect pathways for contaminant deposition and organismal exposure in coastal systems, spatial and temporal variability in contaminant composition, deposition, and uptake patterns are still poorly known. We investigated these patterns for a suite of persistent legacy contaminants including polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs) and chemicals of emerging concern including pharmaceuticals within two Oregon coastal estuaries (Coos and Netarts Bays). ...

- by Elise Granek
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- Environmental Monitoring, Multidisciplinary, Estuaries, Polychlorinated Biphenyls

Occupied from ca. 7040 B.C. to A.D. 1400, the Eel Point Site (CA-SCLI-43) on San Clemente Island, California represents one of the longest sequences of near-continuous marine resource exploitation on the west coast of North America. Faunal remains suggest transitions from heavy exploitation of fur seals and sea lions during the early Holocene, to increased hunting of cetaceans at mid-Holocene, to a focus on sea otters and fish during the late Holocene. These trends are consistent with patterns of overexploitation and economic intensification on the California and Oregon mainland, but they also suggest watercraft-based hunting earlier on the island than elsewhere. Fur seal and sea lion bones mainly represent females and juveniles, indicating that exploitation of island rookeries was guided more by self-interest than by principles of game conservation. Two intervals of temporary site abandonment, ca. 6150–3970 B.C. and A.D. 1020–1400, were both followed by periods of increased marine mammal exploitation and may reflect intervals during which marine mammal populations rebounded. Broad-scale diachronic trends in the zooarchaeological remains do not correlate with flux in paleo-sea temperatures and are best interpreted as products of overhunting and increased use of watercraft over time.

- by Mark Raab
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- Archaeology, Anthropology, Ethnology, Economy

To examine recent developments in the field of phacoemulsification, a literature review was conducted for each system described. The review included peerreviewed articles, information from manufacturers, and meeting presentations by surgeons. Our personal experience with systems we have used forms the underlying basis of our evaluation. Data for erbium:YAG laser phacoemulsification came from an interim summary of the U.S. Food and Drug Administration monitored study. Data for NeoSoniX came from a prospective evaluation of phacoemulsification in 25 eyes performed at the Oregon Eye Surgery Center. The development of new technology has allowed safer, more efficient phacoemulsification. Each surgeon should evaluate new developments to achieve the greatest possible benefit for patients.

- by Mark Packer
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- Peer Review, Literature Review, New Technology, Clinical Sciences
- by Keith Blatner
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- Economic Development, Ecosystem management, Pacific Northwest, Forest Service

Between Point Grenville, Washington, and Point Conception, California (1500 km distance) 21 dune fields record longshore transport in 20 littoral cells during the late Holocene. The direction of predominant littoral transport is established by relative positions of dune fields (north, central, or south) in 17 representative littoral cells. Dune field position is north of cell midpoints in northernmost Oregon and Washington, but is south of cell midpoints in southern Oregon and California. Downdrift sand trapping occurs at significant changes in shoreline angle and/or at bounding headlands that project at least 2.5 km seaward from the general coastal trend. Sand bypassing occurs around small headlands of less than 0.5 km in projection distance. A northward shift of the winter low-pressure center in the northeast Pacific Ocean is modeled from 11 ka to 0 ka. Nearshore current forcing in southern Oregon and northern California switched from northward in earliest Holocene time to southward in late Holocene time. The late Holocene (5-0 ka) is generally characterized by net northward littoral drift in northernmost Oregon and Washington and by net southward littoral drift in southernmost Oregon and California. A regional divergence of net transport direction in central Oregon, i.e. no net drift, is consistent with modeled wind and wave forcing at the present time (0 ka).

- by Roger Hart
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- Geology, Geomorphology, Coastal Dunes, Paleoclimate
- by Mauricio Acuna
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- Near Infrared, Multivariate Analysis, Near Infrared Spectroscopy, Real Time

Isoprene emission capacity measurements are presented from 18 North American oak (Quercus) species and species from six other genera previously found to emit signi"cant quantities of isoprene. Sampling was conducted at physiographically diverse locations in North Carolina, Central California, and Northern Oregon. Emissions from several sun leaves of each species were measured at or near standard conditions (leaf temperature of 303C and photosynthetically active radiation of 1000 mol m\ s\) using environmentally controlled cuvette systems and gas chromatography with reduction gas detectors. Species mean emission capacity ranged from 39 to 158 g C g\ h\ (mean of 86), or 22 to 79 nmol m\ s\ (mean of 44). These rates are 2}28 times higher than those previously reported from the same species, which were summarized in a recent study where isoprene emission rates were assigned based on published data and taxonomy. These discrepancies were attributed to di!erences in leaf environment during development, measurement technique (branch or plant enclosure versus leaf enclosure), and lack of environmental measurements associated with some of the earlier branch enclosure measurements. Mass-based emission capacities for 15 of 18 oak species, sweetgum (Liquidambar styraciyua), and poplars (Populus trichocarpa and P. deltoides) were within ranges used in current biogenic volatile organic compound (BVOC) emission models, while measured rates for the remaining three oak species, Nyssa sylvatica, Platanus occidentalis, Robinia pseudoacacia, Salix nigra, and Populus hybrids (Populus trichocarpa ; P. deltoides) were considerably higher. In addition, mean speci"c leaf mass of the oak species was 30% higher than assumed in current emission models. Emission rates reported here and in other recent studies support recent conclusions that isoprene emission capacities for sun leaves of high emitting species may be better represented by a value of 100$50 g C g\ h\ during hot summer conditions. We also "nd that intermediate isoprene emission rates previously suggested for some tree species may not represent their true emission capacities, and that broadleaf plant species may have either low ( (1.0 g C g\ h\) or very high ( &100 g C g\ h\) genetic capacity to emit isoprene when mature foliage is exposed to a high ambient temperature and light environment. Published by Elsevier Science Ltd.

- by Peter Harley
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- Environmental Engineering, Genetics, Populus, Atmospheric sciences

New Zealand, the United States, and Chile had the best rankings regarding risk from political, commercial, war, or government actions and for the ease of doing business. Conversely, Venezuela, Indonesia, Colombia, and Argentina had high risk ratings, and Brazil, Indonesia, and Venezuela were ranked as more difficult countries for ease of business.

- by Gustavo Balmelli
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- Engineering, Technology, Biomass, Risk

Size at maturity, fecundity, and reproductive periodicity were estimated for the spotted ratWsh, Hydrolagus colliei (Lay and Bennett, 1839), oV the coast of California, Oregon, and Washington. Maximum body size and size at median maturity were greater for females than males. Skeletal muscle concentrations of the steroid hormones testosterone (T) and estradiol (E 2 ) predicted similar, but slightly smaller sizes at maturity than the morphological criterion. Stage of maturity for males was estimated identically using internal organs or external secondary sexual characters, thus allowing non-lethal maturity assessments. Size at median maturity was greater north of Point Conception for females, and north of Cape Mendocino for males. Peak parturition occurred from May to October, with increased concentrations of E 2 in skeletal muscle of females correlating with ovarian recrudescence during November to February. No signiWcant seasonal trends in female T were apparent, but mean female 11-ketotestosterone (11KT) was 300% greater in April than any other month during the parturition season. There was a marginal evidence for increased number and size of ova with maternal size. Extrapolation of the hypothesized 6 to 8-month egg-laying season to observed mean parturition rates of captive specimens yielded an estimated annual fecundity of 19.5-28.9 egg cases. DiVerences in fecundity among higher taxonomic classiWcations of chondrichthyans were detected with chimaeriform Wshes more fecund than lamniform, myliobatiform, squaliform, and rhinobatiform Wshes, and less fecund than rajiform Wshes. Communicated by J.P. Grassle.

- by Gregor Cailliet and +2
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- Marine Biology, International organizations, Biological Sciences, Seasonality

Little information exists on how reservoir fluctuations affect stranding risk for early life stages of salmonids. This study focuses on the effects of hydroelectric-related water level fluctuations in Trail Bridge Reservoir, Oregon, where salmonids, including the bull trout Salvelinus confluentus and spring Chinook salmon Oncorhynchus tshawytscha, which are listed under the U.S. Endangered Species Act, commonly occur. A distance-from-line sampling design was employed using permanently established transects to estimate the magnitude of stranding of juvenile salmonids during 30 surveys over 3 months in spring 2006. All stranded fish observed during field surveys were mapped onto spatially rectified, low-elevation aerial photographs to assess the patterns in stranding. Most fish were stranded in habitats with a slope of less than 6%, typically in interstitial spaces among cobbles, and in ''potholes.'' Fish were stranded in similar numbers following small or large fluctuations, and no relationship was apparent between the range in fluctuation and the number of stranded fish or between the average rate of water surface decline and the number of stranded fish. Based on extrapolation, we estimated that 808 spring Chinook salmon fry and 444 brook trout S. fontinalis fry were stranded in Trail Bridge Reservoir during spring 2006. One dead bull trout was observed, but based on the abrasions, open wounds, and signs of infection that we observed, it died prior to the decline in reservoir elevation. Our findings suggest that stranding in this reservoir could be reduced (while retaining the hydroelectric function of the reservoir) by restricting fluctuations to specific elevations during vulnerable fish migration periods, increasing the slope of areas identified as having a high stranding risk, or both.

- by Sharon Kramer
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- Field Survey, Fisheries Sciences, Oregon, Endangered Species Act

The regional distribution of arsenic and 20 other elements in stream-sediment samples in northern Nevada and southeastern Oregon was studied in order to gain new insights about the geologic framework and patterns of hydrothermal mineralization in the area. Data were used from 10,261 samples that were originally collected during the National Uranium Resource Evaluation (NURE) Hydrogeochemical and Stream Sediment Reconnaissance (HSSR) program in the 1970s. The data are available as U.S. Geological Survey Open-File Report 02-0227. The data were analyzed using traditional dot maps and interpolation between data points to construct highresolution raster images, which were correlated with geographic and geologic information using a geographic information system (GIS). Wavelength filters were also used to deconvolute the geochemical images into various textural components, in order to study features with dimensions of a few kilometers to dimensions of hundreds of kilometers. The distribution of arsenic, antimony, gold, and silver is different from distributions of the other elements in that they show a distinctive high background in the southeast part of the area, generally in areas underlain by the pre-Mesozoic craton. Arsenic is an extremely mobile element and can be used to delineate structures that served as conduits for the circulation of metal-bearing fluids. It was used to delineate large crustal structures and is particularly good for delineation of the Battle Mountain-Eureka mineral trend and the Steens lineament, which corresponds to a post-Miocene fault zone. Arsenic distribution patterns also delineated the Black Rock structural boundary, northwest of which the basement apparently consists entirely of Miocene and younger crust. Arsenic is also useful to locate district-sized hydrothermal systems and clusters of systems. Most important types of hydrothermal mineral deposit in the northern Great Basin appear to be strongly associated with arsenic; this is less so for low-sulfidation epithermal deposits. In addition to individual elements, the distribution of factor scores that resulted from principal component studies of the data was used. The strongest factor is characterized by Fe, Ti, V, Cu, Ni, and Zn and is used to map the distribution of distinctive basalts that are high in Cu, Ni, and Zn and that appear to be related to the Steens Basalt. The other important factor is related to hydrothermal precious metal mineralization and is characterized by Sb, Ag, As, Pb, Au, and Zn. The map of the distribution of this factor is similar in appearance to the one for arsenic, and we used wavelength filters to remove regional variations in the background for this factor score. The resulting residual map shows a very strong association with the most significant precious metal deposits and districts in the region. This residual map also shows a number of areas that are not associated with known mineral deposits, illustrating the utility of the method as a regional exploration tool. A number of these prospective areas are distant from known significant mineral deposits. The deconvolution of the spatial wavelength structure of geochemical maps, combined with the use of large regional geochemical data sets and GIS, permits new possibilities for the use of stream-sediment geochemistry in the study of large-scale crustal features as well as the isolation of mineral-district scale anomalies.

- by Steve Ludington
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- Geology, Geochemistry, Economic Geology, Principal Component Analysis

Radiotelemetry and archival temperature loggers were used to reconstruct the thermal experience of adult spring Chinook salmon (Oncorhynchus tshawytscha) in the highly regulated Willamette River system in Oregon. The study population is threatened and recovery efforts have been hampered by episodically high prespawn mortality that is likely temperature mediated. Over three years, 310 salmon were released with thermal loggers and 68 were recovered in spawning tributaries, primarily at hatchery trapping facilities downstream from high-head dams. More than 190,000 internal body temperature records were collected (mean $ 2800 per fish) and associated with 14 main stem and tributary reaches. Most salmon experienced a wide temperature range (minima $ 8-10°C; maxima $ 13-22°C) and 65% encountered potentially stressful conditions ( Z18°C). The warmest salmon temperatures were in lower Willamette River reaches, where some fish exhibited short-duration behavioral thermoregulation. Cumulative temperature exposure, measured by degree days (DD) above 0°C, varied more than seven-fold among individuals (range ¼ 208-1498 DDs) and more than two-fold among sub-basin populations, on average. Overall, 7272% of DDs accrued in tributaries and 72 28% were in the Willamette River main stem. DD differences among individuals and populations were related to migration distance, migration duration, and salmon trapping protocols (i.e., extended pre-collection holding in tributaries versus hatchery collection shortly after tributary entry). The combined data provide spatially-and temporally-referenced information on both short-duration stressful temperature exposure and the biologically important total exposure. Thermal exposure in this population complex proximately influences adult salmon physiology, maturation, and disease processes and ultimately affects prespawn mortality and fitness. The results should help managers develop more effective salmon recovery plans in basins with marginal thermal conditions.

- by Matthew Keefer and +1
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- Rivers, Biological Sciences, Telemetry, Temperature

At least one large, late Pleistocene flood traveled into the Owyhee River as a result of a rise and subsequent outburst from pluvial Lake Alvord in southeastern Oregon. Lake Alvord breached Big Sand Gap in its eastern rim after reaching an elevation of 1292 m, releasing 11.3 km 3 of water into the adjacent Coyote Basin as it eroded the Big Sand Gap outlet channel to an elevation of about 1280 m. The outflow filled and then spilled out of Coyote Basin through two outlets at 1278 m and into Crooked Creek drainage, ultimately flowing into the Owyhee and Snake Rivers. Along Crooked Creek, the resulting flood eroded canyons, stripped bedrock surfaces, and deposited numerous boulder bars containing imbricated clasts up to 4.1 m in diameter, some of which are located over 30 m above the present-day channel. Critical depth calculations at Big Sand Gap show that maximum outflow from a 1292-to 1280-m drop in Lake Alvord was 10,000 m 3 s À 1. Flooding became confined to a single channel approximately 40 km downstream of Big Sand Gap, where stepbackwater calculations show that a much larger peak discharge of 40,000 m 3 s À 1 is required to match the highest geologic evidence of the flood in this channel. This inconsistency can be explained by (1) a single 10,000 m 3 s À 1 flood that caused at least 13 m of vertical incision in the channel (hence enlarging the channel cross-section); (2) multiple floods of 10,000 m 3 s À 1 or less, each producing some incision of the channel; or (3) an earlier flood of 40,000 m 3 s À 1 creating the highest flood deposits and crossed drainage divides observed along Crooked Creek drainage, followed by a later 10,000 m 3 s À 1 flood associated with the most recent shorelines in Alvord and Coyote Basins. Well-developed shorelines of Lake Alvord at 1280 m and in Coyote Basin at 1278 m suggest that after the initial flood, postflood overflow persisted for an extended period, connecting Alvord and Coyote Basins with the Owyhee River of the Columbia River drainage. Surficial weathering characteristics and planktonic freshwater diatoms in Lake Alvord sediment stratigraphically below Mt. St. Helens set Sg tephra, suggest deep open-basin conditions at~13-14 ka (14 C yr) and that the flood and prominent shorelines date to about this time. But geomorphic and sedimentological evidence also show that Alvord and Coyote Basins held older, higher-elevation lakes that may have released earlier floods down Crooked Creek.

- by Lisa Ely
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- Geology, Geomorphology, Late Pleistocene, Cross Section

South Sister is southernmost and highest of the Three Sisters, three geologically dissimilar stratovolcanoes that together form a spectacular 20 km reach along the Cascade crest in Oregon. North Sister is a monotonously mafic edifice as old as middle Pleistocene, Middle Sister a basalt-andesite-dacite cone built between 48 and 14 ka, and South Sister is a basalt-free edifice that alternated rhyolitic and intermediate modes from 50 ka to 2 ka (largely contemporaneous with Middle Sister). Detailed mapping, 330 chemical analyses, and 42 radioisotopic ages show that the oldest exposed South Sister lavas were initially rhyolitic~50 ka. By~37 ka, rhyolitic lava flows and domes (72-74% SiO 2 ) began alternating with radially emplaced dacite (63-68% SiO 2 ) and andesite (59-63% SiO 2 ) lava flows. Construction of a broad cone of silicic andesite-dacite (61-64% SiO 2 ) culminated~30 ka in a dominantly explosive sequence that began with crater-forming andesitic eruptions that left fragmental deposits at least 200 m thick. This was followed at~27 ka by growth of a steeply dipping summit cone of agglutinate-dominated andesite (56-60.5% SiO 2 ) and formation of a summit crater~800 m wide. This crater was soon filled and overtopped by a thick dacite lava flow and then by N 150 m of dacitic pyroclastic ejecta. Small-volume dacite lavas (63-67% SiO 2 ) locally cap the pyroclastic pile. A final sheet of mafic agglutinate (54-56% SiO 2 )the most mafic product of South Sistererupted from and drapes the small (300-m-wide) present-day summit crater, ending a summit-building sequence that lasted until~22 ka. A 20 kyr-long-hiatus was broken by rhyolite eruptions that produced (1) the Rock Mesa coulee, tephra, and satellite domelets (73.5% SiO 2 ) and (2) the Devils Chain of~20 domes and short coulees (72.3-72.8% SiO 2 ) from N-S vent alignments on South Sister's flanks. The compositional reversal from mafic summit agglutinate to recent rhyolites epitomizes the frequently changing compositional modes of the South Sister locus throughout its lifetime. South Sister is part of a reach of the Cascades unusually active in the last 50 kyr, characterized by high vent density, N-S vent alignments, and numerous eruptive units of true rhyolite (≥72% SiO 2 ) that distinguishes it from much of the Quaternary Cascade arc; these are eruptive expressions of the complex confluence of arc and intraplate magmatic-tectonic regimes.

- by Judy Fierstein
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- Geology, Geochemistry, Geophysics, Volcanology

It is well known that temperature plays an important role in the chemical dynamics of Belousov-Zhabotinsky (BZ) reactions. The five-step Oregonator model of the BZ reaction has been elaborated here to investigate the temperature effect. The bifurcation dynamics has been calculated in the phase space spanned by initial reagents concentration ratio, stoichiometric factor and temperature. The combination of activation energies of the individual reaction steps governs the dependence of oscillation period and amplitude with temperature. The analysis reveals the existence of temperature limits beyond which no oscillations occur.

- by Kenneth Hall
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- Kinetics, Dynamics, Models, Physical sciences

A parametric water balance model was developed based on statistical averaging of the main hydrological processes. The model has a two-layer structure with both a physical and statistical basis for the model parameters. It was developed to fill a need for models with a small number of parameters and of intermediate complexity between a oneparameter simple bucket and more complex hydrologically oriented models with many parameters such as the Sacramento model. The focus was to improve the representation of runoff relative to the simple bucket without introducing the full complexity of the Sacramento model. The model was designed to operate over a range of time steps to facilitate coupling to an atmospheric model. The model can be used for catchment scale simulations in hydrological applications and for simple representation of runoff in coupled atmospheric/hydrological models. An important role for the simple water balance (SWB) model is to assist in understanding how much complexity in representing land surface processes is needed and can be supported with available data to estimate model parameters. The model is tested using rainfall, runoff, and surface meteorological data for three catchments from different climate regimes. Model performance is compared to performance of a simple bucket model, the Sacramento model, and the Oregon State University land surface model. Finally, a series of tests were conducted to evaluate the sensitivity of SWB performance when it is operated at time steps different from the time step for which it was calibrated. so the effects of spatial scale on how surface processes are best represented is an important issue in this study.

- by Fei Chen
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- Atmospheric Modeling, Multidisciplinary, Performance Model, Water balance