Minnesota Site Research Articles

The impact of plant genetic variation and water stress on plant–herbivore interactions

Abstract Plant genotype, water stress and their interaction are among the factors contributing to the susceptibility of plants to herbivory. The plant's nitrogen concentration, a critical and often limiting nutrient, differs with plant genotype and water stress. Still, few studies have investigated the impact of the interaction between genotype and water stress on herbivory and plant nitrogen. We established a common garden in Duluth, MN, of tall goldenrod, Solidago altissima, collected from a local Minnesota site to analyse the effects of goldenrod genotype and water stress on leaf nitrogen and the preference and performance of the chrysanthemum lace bug, Corythucha marmorata. Lace bugs had oviposition, nymph and adult preferences among host plant genotypes, water treatments and among genotype and water treatment combinations. Nymph and adult survival and adult mass varied significantly due to plant genotype, water treatment, the interaction between plant and water treatment and the interaction of treatment with lace bug density. Oviposition preference and offspring performance were significantly positively related. Leaf nitrogen increased with the increasing severity of the water limitation in the absence of lace bugs. However, in the presence of lace bugs, there was no difference in nitrogen among water treatments. We hypothesize that lace bugs reduce leaf nitrogen concentration to a lower threshold and then move between plants until nitrogen concentration equalises among all plants.

Seed sourcing for climate-resilient grasslands: The role of seed source diversity during early restoration establishment.

Restoration advocates for the use of local seed in restoration, but theory suggests that diverse seed sources may enhance genetic diversity and longer term evolutionary potential within restored communities. However, few empirical studies have evaluated whether species and genetic diversity within species impacts plant community composition following restoration. The goal of this research is to compare the effects of single and multi-sourced seed mix treatments on plant community diversity following restoration. Species establishment, abundance, and diversity were compared following two restoration seed mix treatments created to include 14 species commonly used in grassland restoration. We compared the application of seed mixes designed using a single population per species with those containing five populations per species across sites in Minnesota and South Dakota, United States. Early plant establishment and richness mostly reflected non-seeded species across both sites, although seeded species established at a slightly higher rate in year two following restoration. At the South Dakota site, community composition largely reflected changes associated with establishment across the growing season as opposed to seed mix treatment. This contrasted with the Minnesota site, where community composition appeared to be strongly influenced by seed mix treatment. While there is some evidence seed mix treatment may be influencing the emergent community across sites, spatial heterogeneity across the Minnesota restoration site likely influenced diversity in early emergence over that of seed mix treatment. Indeed, varying land-use history across both sites likely contributed to differences in species composition observed at this early stage of the restoration. This suggests that seed mix treatment may have limited impact on early post-restoration emergence diversity relative to the importance of land-use history. However, future monitoring will be needed to evaluate whether the impact of seed mix treatment on community composition changes over time.

Good Samaritan Laws and Graduate Medical Education: A Tristate Survey.

ObjectiveTo assess the awareness of Good Samaritan laws among residents and fellows and the factors affecting the likelihood of a physician-in-training performing a Good Samaritan act.Participants and MethodsA survey was distributed via official e-mail to Mayo Clinic residents and fellows at Mayo Clinic’s 3 locations: Rochester, Minnesota; Scottsdale, Arizona; and Jacksonville, Florida. The survey was open from August 4 to 25, 2015, at the Arizona and Florida sites and from August 10 to 31, 2015, at the Minnesota site. Responses were collected anonymously and analyzed, using descriptive statistics and regression models.ResultsThe survey was sent to 1591 trainees and 19.7% (313) responded. Nearly half the respondents (49%) experienced a medical emergency that required assistance by a medically trained person and reported that increased medicolegal knowledge would increase their likelihood of helping (47%). Almost all (93.6%) felt that awareness of the Good Samaritan laws was essential for a medical professional and reported a need for further education to increase their knowledge (89.3%).ConclusionResidents and fellows asked for education about Good Samaritan laws and suggested that such education may increase their likelihood of helping in medical emergencies.

The Association of Long-Term Exposure to Particulate Matter Air Pollution with Brain MRI Findings: The ARIC Study.

Background:Increasing evidence links higher particulate matter (PM) air pollution exposure to late-life cognitive impairment. However, few studies have considered associations between direct estimates of long-term past exposures and brain MRI findings indicative of neurodegeneration or cerebrovascular disease.Objective:Our objective was to quantify the association between brain MRI findings and PM exposures approximately 5 to 20 y prior to MRI in the Atherosclerosis Risk in Communities (ARIC) study.Methods:ARIC is based in four U.S. sites: Washington County, Maryland; Minneapolis suburbs, Minnesota; Forsyth County, North Carolina; and Jackson, Mississippi. A subset of ARIC participants underwent 3T brain MRI in 2011–2013 (). We estimated mean exposures to PM with an aerodynamic diameter less than 10 or ( and ) in 1990–1998, 1999–2007, and 1990–2007 at the residential addresses of eligible participants with MRI data. We estimated site-specific associations between PM and brain MRI findings and used random-effect, inverse variance–weighted meta-analysis to combine them.Results:In pooled analyses, higher mean and exposure in all time periods were associated with smaller deep-gray brain volumes, but not other MRI markers. Higher exposures were consistently associated with smaller total and regional brain volumes in Minnesota, but not elsewhere.Conclusions:Long-term past PM exposure in was not associated with markers of cerebrovascular disease. Higher long-term past PM exposures were associated with smaller deep-gray volumes overall, and higher exposures were associated with smaller brain volumes in the Minnesota site. Further work is needed to understand the sources of heterogeneity across sites. https://doi.org/10.1289/EHP2152

Realistic simulations of the July 1, 2011 severe wind event over the Buffalo Ridge Wind Farm

AbstractSevere winds from thunderstorm outflows pose a challenge to wind turbine arrays. They can cause significant power ramps and disruption in energy production. They can also cause extreme structural damage to turbines as was seen in the severe storm event over the Buffalo Ridge Wind Farm on July 1, 2011. At this southwestern Minnesota site, blades from multiple turbines broke away and a tower buckled in the intense winds. In this study, we attempt to characterize meteorological conditions over the Buffalo Ridge Wind Farm area during this event. The observational network included NEXRAD radars, automated surface observation stations and a wind profiler. Storm reports from the Storm Prediction Center and damage surveys provided additional insight to the in situ measurements. Even with these datasets, assessing wind speeds around turbine rotors is difficult. Thus, Weather Research and Forecasting model simulations of the event are carried out that consider current and anticipated future operational model setups. This work addresses model spatial resolution versus parameterization complexity. Parameterizations of the planetary boundary layer and microphysics processes are evaluated based on their impact on storm dynamics and the low‐level wind field. Results are also compared with the Wind Integration National Dataset, which utilizes data assimilation and an extensive continental domain. Enhanced horizontal resolution with simplistic parameterization helps increase resolved wind speeds and ramp intensity. Enhanced sophistication of microphysics parameterizations also helps increase resolved wind speeds, improve storm timing and structure and resolve higher values of turbulent kinetic energy in the lowest 1 km of the atmosphere. Copyright © 2017 John Wiley & Sons, Ltd.

Replicating the Safer Sex Intervention: 9-Month Impact Findings of a Randomized Controlled Trial.

To test the effects of the Safer Sex Intervention (SSI) on female adolescents' sexual behavior and possible antecedents of behavior such as sexual health attitudes, knowledge, motivation, intentions, and skills. A randomized controlled trial compared SSI (n = 1196) with no intervention (n = 613) among female adolescents aged 13 to 20 years at 3 sites across the United States from 2012 to 2015. Intent-to-treat impacts were estimated at 9 months after baseline, overall, and for key subgroups. Compared with control participants, SSI participants were less likely to have sexual intercourse without birth control, more likely to report positive attitudes toward protection and intention to use condoms, and more confident of their ability to refuse sex. SSI did not affect sexual risk knowledge or motivation to delay childbearing. Positive impacts on sexual behavior and sexual risk were observed among key subgroups of youths who were aged 18 years or older, Hispanic, not sexually experienced at baseline, and enrolled at the Minnesota site. SSI produced meaningful changes in sexual behavior and sexual risk and successfully addressed some potential antecedents of sexual risk behavior.

2014 presidential address: stop diabetes--it is up to us.

This address was delivered by Elizabeth R. Seaquist, MD, President, Medicine & Science, of the American Diabetes Association (ADA) at the Association's 74th Scientific Sessions in San Francisco, CA, on 15 June 2014. Dr. Seaquist is a professor of medicine at the University of Minnesota in Minneapolis, where she holds the Pennock Family Chair in Diabetes Research. She has been an ADA volunteer since 1987 and has served on several national committees and chaired the Association's workgroup on Hypoglycemia in Diabetes. At the local level, she served a 2-year term as cochair of the ADA EXPO in Minneapolis. Dr. Seaquist is a clinical investigator interested in the complications of diabetes. Her research focuses on the effect of diabetes on brain metabolism structure and function. She directs the University of Minnesota site for the Action to Control Cardiovascular Risk in Diabetes (ACCORD) and Glycemia Reduction Approaches in Diabetes: A Comparative Effectiveness Study(GRADE) trials and has an active clinical practice. She was the 2009 recipient of the ADA's Distinguished Clinical Scientist Award. Dr. Seaquist holds a Bachelor of Arts degree from Vassar College in Poughkeepsie, NY, and a doctorate in medicine from the University of Minnesota. She is board certified in internal medicine and endocrinology, diabetes, and metabolism. The ADA and Diabetes Care thank Dr. Seaquist for her outstanding leadership and service to the Association.

Macro and Microminerals of four Cuphea genotypes grown across the upper Midwest USA

cuphea seed oil can be used for many purposes from motor oil and cosmetic components to jet fuel, because its seeds are a rich source of medium-chain fatty acids (C8:0 to C14:0). Processing cuphea oil to biofuel and other bioproducts of high quality can depend on the heavy metal content of its seed. However, little is known about the macro and micromineral content of its seed. The objective of this study was to evaluate mineral content of cuphea, especially heavy metal content for processing the oil into biofuels/bioproducts and to determine how this may differ across environments. Four cuphea genotypes were evaluated; two of which were semi-domesticated genotypes [PSR23 and HC-10 (Cuphea viscosissima Jacq. × C. lanceolata W.T. Aiton)] and two were wild species (Cuphea wrightii and C. viscosisima (VS-6-CPR-1). The study was conducted at four locations in North Dakota (ND), Minnesota (MN), Iowa (IA), and Illinois (IL). The soil was a Perella silty clay loam at Prosper, ND, a Barnes loam at Morris, MN, a Clarion loam at Ames, IA, and an Osco silt loam at Macomb, IL. PSR23 and HC-10 were directly-seeded in the field and the two wild species were transplanted. All cuphea seeds contained some heavy metals. Although phosphorus (P) and potassium (K) were equally fertilized at all sites, the concentrations of P and K in seeds of PSR23 and HC-10 tended to be lower at the MN site than IA and IL sites, while the lowest P concentration was observed at the MN site for VS-6 and C. wrightii. Among calcium (Ca), magnesium (Mg), and sodium (Na) in cuphea seeds, sodium had the lowest concentration. The average concentrations for microminerals ranged from 40 to 53mgkg−1 for zinc (Zn), from 11.9 to 14.1mgkg−1 for copper (Cu). These concentrations are low compared to those found in many livestock feeds. Lead (Pb) and vanadium (V) were sporadically observed at a few locations. Cobalt (Co) was only detected for VS-6 at IA and C. wrightii at IA and MN, while cadmium (Cd) was only found for HC-10 at ND, PSR23 at IA, and C. wrightii at ND. These results suggest that the concentrations of macro cuphea seeds varied by genotype and environment. This information will be useful for those industries interested in processing cuphea seed oil for manufacturing biofuels, cosmetics, and other specialty chemicals.

Growth environment, harvest management and germplasm impacts on potential ethanol and crude protein yield in alfalfa

An alfalfa (Medicago sativa L) biomass energy production system would produce two products. Leaves would be separated from stems to produce a protein feed for livestock while stems would be processed to produce ethanol. Therefore, maximum yields of both leaves and stems are essential for profitability of this biomass production system. Our objective was to evaluate the impact of growth environment (locations, years and plant density) and harvest maturity stage (early bud (4 annual cuts) and late flower (3 annual cuts)) on leaf crude protein and potential ethanol yields for four alfalfa germplasms, two with high forage quality, and two non-lodging biomass types. Potential ethanol yield was greater at late flower compared to early bud, while leaf crude protein concentration was similar at the two harvest maturity stages at both locations. Leaf crude protein yield was greater at the Minnesota (MN) site compared to Wisconsin (WI) site. The two non-lodging biomass germplasms had greater potential ethanol yield compared to the high forage quality cultivars in WI, but no differences among the alfalfa germplasms were found for ethanol yield at MN. In WI, no differences were found among the germplasms for leaf crude protein yield, but the high quality cultivars had greater leaf crude protein yield than the non-lodging germplasms in MN. While germplasm differences were found for leaf crude protein and potential ethanol yields, the environmental influences of harvest date and locations had the greatest impact on these two alfalfa biomass energy products.

Investigating Research and Accessing Reproductive Material

Dan Markingson was acutely psychotic when University of Minnesota psychiatrists enrolled him in 2004 into the local arm of a controversial multisite CAFE clinical trial, an AstraZeneca-sponsored comparative study of three of the newer neuroleptic drugs. He had been repeatedly judged incompetent to make his own treatment decisions—including as late as two days before enrolling in the study—and was involuntarily committed after making delusional threats to his mother. But his commitment was suspended by a “stay of commitment order” from a district court judge that allowed him to leave the hospital under court-imposed conditions, a key condition being that he had to follow the treatment instructions of his treating psychiatrist, Dr. Olson. Shortly after the stay of commitment order, Dr. Olson proposed that Markingson participate in the clinical trial (of which Olson was the lead investigator at the Minnesota site). Markingson was surprisingly assessed as competent to consent to participate in this trial. Seventeen days after his enrolment in the trial, he moved to a halfway house. His mother, Mary Weiss, believing his condition was deteriorating, attempted repeatedly to get her son out of the study. Notes from a social worker and an occupational therapist also suggested that he was not doing well while in the trial. At one point, Weiss explicitly warned the research team that her son was in serious danger of killing himself. Her warnings were ignored. On May 8, 2004, Markingson committed a violent suicide. These are, in short, the facts of a case that has created turmoil in the bioethics and research communities, particularly in North America, since the St. Paul, Minnesota, Pioneer Press reported on it in 2008 in a series of articles. That the case never completely faded away in the 5 years following the first media report and continues to be the focus of heated debate is due to ongoing actions by Mary Weiss and her friend, Mike Howard, as well as the relentless questioning and reporting by Carl Elliott, a University of Minnesota professor of bioethics. After Bioethical Inquiry (2014) 11:11–19 DOI 10.1007/s11673-013-9503-2

Earthworm invasion alters enchytraeid community composition and individual biomass in northern hardwood forests of North America

European earthworms are invading many ecosystems worldwide and fundamentally transform habitats by acting as dominant ecosystem engineers. However, there is little knowledge of the consequences of earthworm invasion on the composition and diversity of native soil organisms. Particularly functionally similar groups, such as enchytraeids (Annelida: Enchytraeidae), may be affected through changes in the chemical and physical properties of the soil, but also due to competition for resources. In 2010–2011, we studied the impact of earthworm invasion on enchytraeids at two sites in the northern hardwood forests of North America: one site within the Chippewa National Forest in northern Minnesota and one site in the Chequamegon-Nicolet National Forest in northern Wisconsin, USA. At each site, three plots were sampled along a transect, representing (1) a non-invaded or very slightly invaded area, (2) the leading edge of earthworm invasion and (3) a heavily invaded area with an established population of the anecic earthworm Lumbricus terrestris (among other species). In total, 29 enchytraeid (morpho)species were identified (some yet to be formally described, several first or second records for the continent); of those 24 occurred at the Minnesota site and 17 at the Wisconsin site. The structure of enchytraeid assemblages differed significantly among the three invasion stages, although this was not equally pronounced at the two sites. Each stage was characterized by one or several indicator species. Mean enchytraeid densities (10,700–30,400individuals/m2) did not differ significantly among the invasion stages, but were lowest at the leading edge of earthworm invasion at both sites. In the heavily invaded plot at the Minnesota site, the mean enchytraeid density and biomass in L. terrestris middens were significantly higher than in soil in-between the middens. This was due to a pronounced effect of L. terrestris middens in the uppermost 3cm of soil. Differences in biomass among earthworm invasion stages were most apparent for mean individual biomass. This was significantly higher in the heavily invaded area than at the leading edge or in the non-invaded area at the Minnesota site. Compositional changes of the enchytraeid assemblage are likely to result in changes in the functioning of soil foods webs. Our results suggest that earthworm invasions can cause a loss of native species in soil, including heretofore unknown ones, that might go unnoticed.

The Differential Response of Surface Fluxes from Agro-ecosystems in Response to Local Environmental Conditions

Meeting the competing demands for freshwater of the urban, industrial, and agricultural communities is increasingly challenging as the global population continues to grow and the need for potable water, food, fiber, and fuel grows with it. One of the keys to meeting these demands is maximizing the efficiency of water use in agricultural applications. Toward this end, a thorough understanding of the factors driving evapotranspiration and their response to spatiotemporal variations in local environmental conditions is needed for the development and validation of numerical and remote sensing-based models. Moreover, because these exchange processes are strongly nonlinear, scaling measurements collected at one scale to another remains a nontrivial task. In an effort to identify the key environmental drivers controlling the latent heat flux (λE) from agro-ecosystems and their potential impacts on upscaling in-situ flux measurements, eddy covariance and micrometeorological data collected over maize and soy at three distinct sites located in Maryland, Iowa, and Minnesota, respectively were evaluated for the years between 2007 and 2011. The magnitudes of the evaporative fluxes were comparable for measurements collected during clear-sky days with similar environmental conditions; on average, the measurements of λE agreed to within 50W m-2, or approximately 10%. When considered in terms of evaporative fraction (fe), however, there were marked differences among the sites. For example, while the magnitude and diurnal pattern of fe for mature maize at the Minnesota site was nearly constant (fe = 0.66) during the day, fe at both the Maryland and Iowa site increased steadily during the day from a minimum value near 0.68 at midmorning to peak value of 0.87 in the afternoon. These differences appear to be primarily linked to differences in soil moisture and vegetation density at the various sites. As such, this research underscores the impact of local environmental conditions in controlling land-atmosphere exchange processes. It also underscores the importance accurately describing local environmental conditions when modeling surface fluxes.

Reduced renal function and sleep-disordered breathing in community-dwelling elderly men

Background Sleep-disordered breathing (SDB) may increase the risk of cardiovascular disease (CVD) and death in chronic kidney disease (CKD). However, the association between mild reductions in renal function and SDB is uncertain. Methods We studied 508 community-dwelling men aged ⩾67 years (mean 76.0 ± 5.3) who were enrolled at the Minnesota site for the Minneapolis center of the Outcomes of Sleep Disorders in Older Men (MrOS) sleep study and had serum cystatin-C and creatinine measured coincident with overnight polysomnography. CKD was defined as estimated glomerular filtration rate (eGFR) <60 ml/min/1.73 m 2 using Cockcroft–Gault (CG), modification of diet in renal disease (MDRD) and Mayo Clinic formulae. SDB was defined by a respiratory disturbance index (RDI) ⩾15 events/h. Results Mean cystatin-C was 1.21 ± 0.30 mg/L, and mean creatinine was 1.09 ± 0.23 mg/dL. Median RDI was 7.0 events/h (range 0–73). Higher quartiles of cystatin-C were associated with higher mean RDI ( p for trend = 0.007). This association persisted after adjustment for age and race ( p for trend = 0.03), but not after adjustment for body mass index (BMI, p for trend = 0.34). After adjusting for age, race, BMI, diabetes, hypertension, and CVD, CKD defined by the Mayo Clinic formula, but not CG or MDRD, was associated with a higher odds of SDB [odds ratio (OR) 1.95, 95% confidence interval (CI) 1.04–3.65, p = 0.04]. Conclusions Older men with reduced renal function as defined by higher cystatin-C concentration have higher average RDI. This effect is explained by higher BMI in men with higher cystatin-C. CKD defined by the Mayo Clinic formula is independently associated with twofold higher odds for SDB. Therefore, reduced renal function may be associated with SDB in older men.

Carbon-13 Fractionation of Relic Soil Organic Carbon during Mineralization Effects Calculated Half-Lives

The 13 C natural abundance approach for determining soil organic C (SOC) stability and turnover has been used to determine SOC mineralization kinetics. These calculations generally assume that 13 C fractionation during relic SOC and unharvested biomass mineralization is insignificant. The objective of this study was to determine the impact of this assumption on calculated relic SOC half-lives. Study sites were located in Minnesota and South Dakota. At the Minnesota site, SOC contained in the surface 30 cm of soil in a fallowed area decreased from 90.8 to 73.2 Mg ha -1 during a 22-yr period. Associated with this decrease was a 0.72%o increase in the soil δ 13 C values (from -18.97 to -18.25%o). Based on these values, the Rayleigh fractionation constant (e) of relic SOC was -3.45%o. At the South Dakota site, SOC decreased 10% (2.8 ± 1.8 g kg -1 ) and δ 13 C increased 3.2% (0.548 ± 0.332%o) during a 5-yr period. The Rayleigh fractionation constant for this experiment was -6.94%o (±4.74‰). In a separate experiment, the δ 13 C value of corn (Zea mays L.) and soybean [Glycine max (L.) Merr.] residue remained unchanged after 4 mo. The impact of 13 C enrichment during relic C mineralization on calculated C budgets depends on the type of residue returned to the soil. A simulation study showed that for systems where C 4 residues are returned to soil derived from C 3 and C 4 plants, not considering 13 C enrichment during relic SOC mineralization will result in underestimating relic SOC half-lives and overestimating the contribution of fresh C 4 biomass in the SOC. The effect of 13 C enrichment during relic SOC and unharvested biomass mineralization had cumulative impacts on C budgets and did not cancel each other out. The reverse was true for C 3 biomass. To minimize these errors, SOC maintenance rate experiments should measure 13 C enrichment during relic SOC and unharvested biomass mineralization.

First Report of Bentgrass Seed Gall Nematode, Anguina agrostis, in Virginia and Minnesota.

On August 24, 2003, during a foray for grasses infected with fungi, redtop creeping bentgrass (Agrostis stolonifera L.) was collected on Butt Mountain Lookout near an abandoned fire tower with coordinates 80°37'40.3″ W and 37°22'14.0″N at an altitude of 1,284 m overlooking the New River between the towns of Pembroke and Ripplemead, VA. Seed heads with very elongated glumes, lemmas, and paleas were very common, and the incidence rate was nearly 95% on the basis of symptomatic plants in the immediate area surrounding the tower comprising more than 5 ha of a grassy meadow. Close examination revealed the occurrence of elongated, blackish galls replacing the ovaries and containing Anguina agrostis (Steinbuch, 1799) Filipjev, 1936. Nematode cultures were established and maintained on red top creeping bentgrass (A. stolonifera) in a greenhouse. Identification was based on morphology and measurements of juveniles L = 407 + 22 (376-418) μ, stylet L = 18.5 + 1.7 (17.0-21.3) μ males L = 351 + 17 (339-367) μm; and females L = 455 + 33. Examination of specimens collected previously by C. Roane revealed that another population of Anguina agrostis was also found on August 9, 1990 parasitizing the same host growing along Echo Trail near Big Lake Lodge Rd. in St. Louis County, MN. The infestation at the Virginia site may have been from sowing infested seeds at the disturbed construction site for the fire lookout tower and other buildings. However, the occurrence at the Minnesota site is less likely to be anthropogenic. Voucher specimens from both locations were placed in the Virginia Tech Nematode Collection, and voucher cultures are maintained in the Virginia Tech Nematode Culture Collection.

A Simple Method for Calculating Growth Rates of Petroleum Hydrocarbon Plumes

Consumption of aquifer Fe(III) during biodegradation of ground water contaminants may result in expansion of a contaminant plume, changing the outlook for monitored natural attenuation. Data from two research sites contaminated with petroleum hydrocarbons show that toluene and xylenes degrade under methanogenic conditions, but the benzene and ethylbenzene plumes grow as aquifer Fe(III) supplies are depleted. By considering a one-dimensional reaction front in a constant unidirectional flow field, it is possible to derive a simple expression for the growth rate of a benzene plume. The method balances the mass flux of benzene with the Fe(III) content of the aquifer, assuming that the biodegradation reaction is instantaneous. The resulting expression shows that the benzene front migration is retarded relative to the ground water velocity by a factor that depends on the concentrations of hydrocarbon and bioavailable Fe(III). The method provides good agreement with benzene plumes at a crude oil study site in Minnesota and a gasoline site in South Carolina. Compared to the South Carolina site, the Minnesota site has 25% higher benzene flux but eight times the Fe(III), leading to about one-sixth the expansion rate. Although it was developed for benzene, toluene, ethylbenzene, and xylenes, the growth-rate estimation method may have applications to contaminant plumes from other persistent contaminant sources.

Functional recovery and exercise behavior in men and women 5 to 6 years following coronary artery bypass graft (CABG) surgery.

Improvement following coronary artery bypass graft (CABG) surgery has been reported to be less in women than men. Relationships between exercise behavior and functional status of men and women 5 to 6 years after CABG have not been examined in a representative patient sample. This study compared the 5- to 6-year recovery in a cohort of 184 patients at the Minnesota site of the Post CABG Biobehavioral Study. Data were collected by telephone interview and self-administered questionnaires. Results showed that women had lower physical ( p </=.004) and social ( p=.001) functioning scores; men were more likely to participate in regular exercise ( p =.01). Exercisers had higher functional status scores. ANCOVA demonstrated that differences in measures of functional status by exercise category were maintained even after controlling for age, sex, and symptom severity ( p </=.01). In conclusion, individuals who exercised had more positive functional outcomes 5 to 6 years post-CABG.

Use of In Situ Burning as an Oil Spill Response Tool: Follow-Up of Four Case Studies

ABSTRACT Four in situ burning sites that varied widely in the physical setting, oil type, timing of the burn, and post-burn treatment were assessed 0.5–1.5 years post-burn: two condensate spills in intertidal marshes at Mosquito Bay, LA in April 2001 and near Sabine Lake, LA in February 2000; crude oil spill in a ponded wetland in Minnesota in July 2000; and a spill of diesel in a salt flat/wetland north of Great Salt Lake, UT in January 2000. When used quickly after a release, burning is most effective at reducing damage to vegetation and the areal extent of impact. Where crude oil was burned within hours after the release at the Minnesota site, the impact area was restricted to 3 acres. In contrast, the diesel in the Utah spill spread over 38 acres within 3 days. The window of opportunity for in situ burning to be an effective means of oil removal can be days to months, depending on the spill conditions. The condensate spill at Mosquito Bay site was effectively burned 6–7 days after the release was reported. For spills with snow and ice cover, burning may still be effective months later. In fact, it may be necessary to consider additional burns during thaw periods and during the final thaw. Burning will not reduce the toxic effects of the oil that occurred prior to the burn. It can, however, be very effective at reducing the extent and degree of impacts by quickly removing the remaining oil. In three of the four case studies, the area burned was significantly larger than the oiled area (up to 10 x). Healthy, green, unoiled vegetation is not always an effective fire break, particularly downwind; fires can quickly jump the kinds of fire breaks placed during spill emergencies in wetlands (e.g., vegetation laid down by the passage of airboats).

A regional survey of malformed frogs in Minnesota (USA) (Minnesota malformed frogs).

In late 1995, school children discovered malformed frogs in a south central Minnesota pond. Press coverage resulted in numerous citizen reports of frog malformation across Minnesota in 1996. After some initial site investigation, 3 affected frog sites and 4 nearby reference sites were selected for more detailed evaluation. Field biologists made 89 visits to study sites beginning spring 1997 through fall 1999 to examine the number and type of frog malformations. Over 5,100 Leopard frogs (Rana pipiens) were captured and examined at all study sites. Water elevations and associated littoral inundation were recorded from 1997-2000. Results indicate that malformation occurred at all study sites above historical background levels. Rana pipiens malformation across all sites over three seasons averaged 7.9% and ranged from 0 to 7% at reference sites and 4 to 23% at affected sites. At one northern Minnesota site, mink frog (Rana septentrionalis) malformation was 75% in 1998. A site characteristic common to the most affected sites was an elastic zone of littoral inundation. Climate driven hydrologic variation likely influenced water depth and associated breeding locations.

Spring Migration Patterns of Male Red-Winged Blackbirds (Agelaius phoeniceus) from Two Migratory Roosts in South Dakota and Minnesota

-During March 1985 male red-winged blackbirds (Agelaius phoeniceus) were marked with aerially applied fluorescent-colored pigments at two migratory roost sites in southeastern South Dakota and western Minnesota to determine their dispersal to breeding areas. Postspray samples revealed that approximately 54% (1.58 million) of the males present were marked with at least one of four pigments used. During late spring, breeding males were shot in 16 predetermined collecting areas in four N-central states in the United States and three central Canadian provinces. Of 3289 males collected, 555 (16.9%) were marked with one or more pigments; 86.8% (482) of the marked birds were from the South Dakota marking site and 13.2% (73) from the Minnesota site. The 16 collecting areas where male redwings were shot were grouped into six recovery regions for chi-square analysis. Results showed unequal proportions of marked breeding males among the recovery areas (P = <0.001). Temporal use of the South Dakota roost site by migrating males also affected breeding male distribution (P = <0.001). Inadequate sample sizes precluded analysis of temporal distribution of marked birds from the Minnesota marking site. Although marked redwings were dispersed over several thousand square kilometers from South Dakota to Alberta, Canada, 76% of the marked male redwings from South Dakota were concentrated in southern Saskatchewan and N-central North Dakota; 74% of the marked birds from Minnesota were concentrated more easterly in southern Manitoba, northeastern North Dakota and northwestern Minnesota. The N-northwestward distances traveled by migrating male redwings from marking sites to breeding areas was significantly different (P = 0.006) among groups marked at different time intervals at each site. Distances traveled ranged from 856 km to 1093 km.