Southeastern Nebraska Research Articles

An Analysis of Audit Scores of Adolescent Offenders in Two Midwestern Counties

The Alcohol Use Disorder Identification Test provides an accurate measure of risk associated with alcohol-related problems across sex, age, and cultures. As a recommended screening tool to detect patients who are appropriate candidates for brief, preventive alcohol interventions, it was given to 78 adolescents in a diversion program for drunk drivers in two southeastern Nebraska counties during routine alcohol-dependency evaluations. The subjects were grouped by age (18 and younger and over 18 years) and by sex. Based on a previous study, it was hypothesized that the responses to the first three AUDIT questions, related to alcohol consumption, would reflect sex and age differences. A 2 x 2 analysis of variance of scores on separate items indicated significant main effects for age (F1,74= 10.40, p<.002) for Question 1 with older boys' and girls' groups reporting they have drinks containing alcohol more frequently, for sex (F1,74= 14.65, p<.001) on Question 2 with the older boys' group reporting more frequent drinking on a typical day, and for age (F1,74 = 7.74, p>.01), and sex (F1,74= 4.12, p< .05) on Question 3 with the older boys' group indicating that they more frequently consumed six or more drinks on one occasion. It is recommended that the AUDIT-C be included in drug and alcohol assessments with adolescents similar to those tested here, and professionals be alert to the possibilities of sex and age differences in response to questions related to consumption.

Hybrid hazelnut oil characteristics and its potential oleochemical application

The demand for vegetable oils as alternatives to petroleum is growing. Vegetable oils offer performance advantages and are environmentally friendly. Soybean oil is one of the promising resources and has been studied extensively. However, soybean oil lacks thermal and oxidative stability and has undesirable cold flow properties. These disadvantages are directly related to its fatty acid composition. Therefore, new varieties with superior oil traits are needed. Hybrid hazelnut oil is just such an attractive raw material. The objective of this study was to investigate hybrid hazelnut oil fatty acid composition and several other important properties in view of potential oleochemical applications. Hazelnut oil, derived from hybrid hazelnuts ( Corylus sp. L .) grown in southeastern Nebraska, was extracted using a Soxhlet extractor. The oil contents of 25 different hybrid hazelnut samples ranged from 51.4% to 75.1% of the dry weight of nut kernels. Fatty acid profiles were analyzed by gas chromatography. It was found that oleic and linoleic acids comprised more than 90% of fatty acids in the oil. Oxidative onset temperature (OOT) was used as an indicator of thermal stability. The OOT of the hazelnut oils were in the range of 184.7–190.4 °C, which were higher than that of soybean oil (148.4 °C). The cloud points of hazelnut oils (−12.4 to −14.9 °C) were lower than that of soybean oil (−9.9 °C). The iodine values were in the range of 90.6–97.4. The kinematic viscosity of hazelnut oil was 65.7 ± 2.2 mm 2/s at 22 °C. These initial analyses suggest that hazelnut oil is a potential feedstock for oleochemicals.

Evaluation of methods for determination of hydraulic properties in an aquifer–aquitard system hydrologically connected to a river

Field and laboratory methods have been used to determine the hydraulic properties in a multiple-layer aquifer–aquitard system that is hydrologically connected to a river. First, hypothetical pumping tests in aquifer–aquitard systems were performed to evaluate the feasibility of MODFLOW-PEST in determining these parameters. Sensitivity analyses showed that: the horizontal hydraulic conductivity in the aquifer has the highest composite sensitivity; the vertical hydraulic conductivity has higher composite sensitivity than the horizontal hydraulic conductivity in the aquitard; and a partial penetration pumping well in an aquifer layer can improve the quality of the estimated parameters. This inverse approach was then used to analyze a pumping-recovery test conducted near the Platte River in southeastern Nebraska, USA. The hydraulic conductivities and specific yield were calculated for the aquitard and aquifer. The direct-push technique was used to generate sediment columns; permeameter tests on these columns produced the vertical hydraulic conductivities that are compatible with those obtained from the pumping-recovery test. Thus, the combination of the direct-push technique with permeameter tests provides a new method for estimation of vertical hydraulic conductivity. The hydraulic conductivity, determined from grain-size analysis, is smaller than the horizontal one but larger than the vertical one determined by the pumping-recovery test.

Sequence stratigraphic controls on synsedimentary cementation and preservation of dinosaur tracks: Example from the lower Cretaceous, (Upper Albian) Dakota Formation, Southeastern Nebraska, U.S.A.

A thin cemented sandstone bed in the Upper Albian Dakota Formation of southeastern Nebraska contains the first dinosaur tracks to be described from the state. Of equal importance to the tracks are stable-isotope (C, O) analyses of cements in the track bed, especially in the context of data derived from generally correlative strata (sandstones and sphaerosiderite-bearing paleosols) in the region. These data provide the framework for interpretations of paleoenvironmental conditions, as well as a novel approach to understanding mechanisms of terrestrial vertebrate track preservation. High minus-cement-porosity (> 47%) and low grain-to-grain contacts (∼2.5) in the track bed indicate early (pre-compaction) lithification. Although phreatic cements dominate, the history of cementation within this stratigraphic interval is complex. Cathodoluminescence petrography reveals two distinct calcite zones in the track-bearing horizon and four cement zones in stratigraphically equivalent strata from a nearby section. The earliest calcite cements from both localities are likely coeval because they exhibit identical positive covariant trends ( δ 18O values of − 9.89 to − 6.32‰ and δ 13C values of − 28.01 to − 19.33‰ VPDB) and record mixing of brackish and meteoric groundwaters. All other calcite cements define meteoric calcite lines with δ 18O values clustering around − 9.42‰ and − 8.21‰ VPDB from the track-bearing horizon, and − 7.74‰, − 5.81‰, and − 3.95‰ VPDB from the neighboring section. Distinct meteoric sphaerosiderite lines from roughly correlative paleosols serve as a proxy for locally recharged groundwaters. Back-calculated paleogroundwater δ 18O estimates from paleosol sphaerosiderites range from − 7.4 to − 4.2‰ SMOW; whereas, meteoric calcite lines from the track horizon are generally more depleted. Differences in cement δ 18O values record changes in paleogroundwater recharge areas over time. Early calcite cements indicate mixing of fresh and brackish groundwaters during the syndepositional lithification of the track horizon. Later calcite cements, however, indicate recharge from a larger catchment basin that extended far inland. Therefore, the cements likely record a rise and subsequent fall in relative sea level. We conclude that scrutiny of the cement isotope geochemistry of genetically significant surfaces, especially track beds, can provide new data for interpreting sea level change.

Seasonality and Adult Habitat Use by FourDiabroticaSpecies at Prairie-Corn Interfaces

Although Diabrotica pest species have been well studied in field corn, Zea mays L., relatively little is known about adult habitat use by pest and nonpest species at prairie-corn interfaces. Therefore, the objective of this work was to compare seasonal patterns of beetles of four Diabrotica species and their use of remnant prairie and adjacent field corn habitats in southeastern Nebraska. The study was conducted at five sites in 2001 and continued at three sites in 2002. The Diabrotica species included D. barberi Smith and Lawrence, D. cristata (Harris), D. virgifera virgifera LeConte, and D. undecimpunctata howardi Barber. Cucurbitacin vial traps were used to monitor Diabrotica populations. Available flowers and Diabrotica use of these flowers were also documented. The virgifera group species (D. barberi, D. cristata, and D. v. virgifera) were closely tied to a primary habitat, corn or prairie, but moved to secondary habitat if relative attractiveness of food sources in the primary habitat decreased; these three species had high initial population densities that decreased over the season. The one fucata group species (D. u. howardi) was found in various habitats, with low initial densities that increased over the season. Habitat type and contrasts in plant phenology seem to be key factors that influenced habitat choice by Diabrotica species; this especially affected the level of noncorn habitat use by pest species D. v. virgifera and D. barberi. Use of crop and noncrop parts of the agroecosystem by pest species suggests that a more holistic approach rather than a single field view may be appropriate when managing corn rootworms.

Prevalence and Serovars of Salmonella in the Feces of Free-Ranging White-Tailed Deer (Odocoileus virginianus) in Nebraska

To determine the prevalence and serovars of Salmonella in free-ranging deer, we cultured feces from white-tailed deer (Odocoileus virginianus) harvested by hunters during a regular firearm season in southeastern Nebraska (USA). We recovered Salmonella from 5 (1%; 95% confidence interval: 0.37-2.20%) of 500 samples and identified four different Salmonella enterica serovars [Litchfield (1), Dessau (1), Infantis (2), and Enteritidis (1)]. Although the prevalence of Salmonella in free-ranging deer appears to be low, the serovars recovered are known to be pathogenic to humans and animals.

A Profile of Adolescent Alcohol Offenders in Two Rural Midwestern Counties

Screening tools specifically developed for use with adolescents may be more sensitive predictors of relapse or recidivism than self-report inventories typically used to screen adults. 70 adolescents in a program for drunk drivers in two counties in southeastern Nebraska were given both the CRAFFT and the Alcohol Use Disorder Identification Test questionnaires during routine alcohol-dependency evaluations. The Michigan Alcoholism Screening Test was also given to 28 subjects selected at random. 11 boys and 6 girls did not successfully complete the program. Significant correlations obtained for AUDIT scores for both the CRAFFT (r69=.65, p<.01) and failure to complete diversion (r69=.23, p<.05). Subjects were grouped by age (18 and younger and over 18 years) and by sex. A 2 x 2 analysis of variance for scores on the AUDIT indicated significant main effects for both age (F1,66=4.86, p<.05) and sex (F1.66=5.96, p<.01). MAST and CRAFFT scores showed no age or sex differences. The AUDIT might be included in drug and alcohol assessments with similar samples of adolescents.

SPATIAL HETEROGENEITY IN THE PARASITE COMMUNITIES OF CREEK CHUB (SEMOTILUS ATROMACULATUS) IN SOUTHEASTERN NEBRASKA

The intestinal helminth communities of creek chub (Semotilus atromaculatus) were studied in the streams of southeastern Nebraska to characterize spatial variation, to determine whether drainages act as regional species pools, and to examine the spatial patterning of individual parasite species within and among drainages. Creek chub were sampled in the summer of 2003 and the spring of 2004 at each of 12 sites distributed evenly among 3 drainages in the Big Nemaha River watershed. Four intestinal helminths were recovered: Allocreadium lobatum, Proteocephalus sp., Rhabdochona canadensis, and Paulisentis missouriensis. Host size had little or no effect on the composition of the parasite communities of creek chub, either among individual fish or among samples. In contrast, drainage and sample date explained 82% of the variation in mean infracommunity species richness among samples, and 62% of the variation in mean infracommunity abundance among samples. Drainage differences were determined by the distributions of P. missouriensis and R. canadensis; whereas, A. lobatum and Proteocephalus sp. were more uniformly distributed among drainages. Each drainage was characterized by a unique pattern of species diversity at infracommunity, component community, and drainage levels of organization.

Soybean row spacing and weed emergence time influence weed competitiveness and competitive indices

Weed competitiveness can be quantified with the concept of competitive index (CI), a relative scale of weed competitiveness. Field studies were conducted in 2002 and 2003 in northeastern and southeastern Nebraska to evaluate the influence of soybean row spacing and relative weed emergence time on the competitiveness of major weed species in soybean. Ten weed species were seeded in soybean spaced 19 and 76 cm apart at the planting, emergence, and first trifoliate leaf stages of soybean. Total weed dry matter (TDM), weed plant volume, and percent soybean yield loss were arbitrarily selected as a base for determining the CI for each weed species. Soybean yield loss was the least variable parameter used to quantify weed competitiveness and rank their CIs. In general, weeds grown with soybean planted in 19-cm rows produced less TDM, plant volume, and reduced soybean yield less than weed species grown in 76-cm rows. Later-emerging weeds produced less TDM, plant volume, and reduced soybean yield less than the early-emerging ones. In general, broadleaf species were more competitive than grass weed species. Common sunflower was the most competitive weed species in this study.

(385) Phenolic Analysis of Selected Grape Cultivars

Phenolic levels have been analyzed in several grape cultivars that are suited for growing in southeastern Nebraska. The phenolic levels of these cultivars are not known to have been previously published. The polyphenol content of fruits and fruit products such as wine have been shown to be directly correlated to the antioxidant potential of the product. Antioxidants help to prevent the effects of aging and age-associated diseases. The grape cultivars in the study are grown primarily for wine production, but also as fresh table grapes and for making juice and jellies. The total phenolic content is being analyzed by the Folin-Ciocalteu method. Of the red grapes, `St. Croix' and `Frontenac' have the highest levels of polyphenols, followed by `Chambourcin' and `deChaunac', with levels varying from 1.4–4.9 mg·g-1 (polyphenols/grape), measured as gallic acid equivalents (GAE). The white grapes `Vignoles' and `LaCrosse' have total phenolic levels of 1.4 to 2.2 mg·g-1 (polyphenols/grape), also measured as gallic acid equivalents (GAE).

The Elk Creek Carbonatite, Southeast Nebraska–An Overview

A framework geophysical program in southeastern Nebraska during 1970 identified a near-circular feature having gravity relief of about 8 mgal and a magnetic anomaly of about 800 gammas. Analysis of the geophysical data provided a model of a cylindrical mass of indefinite length with a radius of 5500 ft (1676 m) and beveled at the basement surface at about 600 ft (183 m). At the approximate depth at which Precambrian rocks were expected, the initial test hole (2-B-71) encountered an iron-rich weathered zone overlying carbonate-rich rock. The carbonate rocks consist essentially of dolomite, calcite, and ankerite and lesser amounts of hematite, chlorite, phlogopite, barite, serpentine, pyrochlore, and quartz and contain barium, strontium, and rare earths. Total REE, P2O5, and 87Sr/86Sr ratios confirm the carbonatite identification. Texturally, the rocks range from fragmental to contorted to massive. Associated with the carbonatite are lesser amounts of basalt, lamprophyre, and syenite. Additional exploratory drilling has provided about 80,000 ft (24,384 m) of rock record and has penetrated about 3400 ft (1038 m) of carbonatite. The carbonatite is overlain by marine sediments of Pennsylvanian (Missourian) age. The surrounding Precambrian basement rocks are low-to medium-grade metamorphic gneiss and schist of island arc origin and granitic plutons. The Elk Creek carbonatite is located near the boundary between the Penokean orogen created at about 1.84 Ga (billion years) and the Dawes terrane (1.78 Ga) of the Central Plains orogen. This boundary strongly influenced the geometry of both the Midcontinent Rift System (1.1 Ga) and the Nemaha uplift (0.3 Ga). It is assumed that the emplacement of the Elk Creek carbonatite (0.5 Ga) was influenced similarly by the pre-existing tectonic sutures.

Tillage and Rotation Interactions for Corn and Soybean Grain Yield as Affected by Precipitation and Air Temperature

Reduced tillage, including no‐till, and crop rotation are common practices for corn (Zea mays L.) and soybean [Glycine max (L.) Merr.] production in the Midwest. Benefits of no‐till vary with latitude and cropping system. This study was conducted to evaluate the influence of seasonal temperature and precipitation on the effects of primary tillage (plow, disk, chisel, subsoil, ridge‐till, and no‐till) and rotated and continuous corn and soybean production under rainfed conditions over 16 yr in southeastern Nebraska. Corn and soybean produced less grain with greater summer temperatures. Corn yield increased with less spring and more summer rainfall. Tillage and rotation practices affected corn grain yield; but only rotation affected soybean yield. Corn produced less grain with no‐till than with plow. The tillage × year interaction was significant for both crops; the yield advantage for plow was less during seasons with warmer springs. Soybean grain yield was less responsive to favorable environments with the chisel than other tillage treatments. Grain yield was greater with rotation than continuous cropping for both corn (7.10 vs. 5.83 Mg ha−1) and soybean (2.57 vs. 2.35 Mg ha−1). The benefit of rotation in terms of grain yield was greatest for corn during years with cool springs. The benefit of rotation for soybean grain yield did not vary with weather conditions. Seasonal temperature and rainfall patterns influenced the effects of tillage and rotation on corn yield. In contrast, for soybean, only the pattern of temperature influenced the effect of tillage on yield.

Tillage and Rotation Interactions for Corn and Soybean Grain Yield as Affected by Precipitation and Air Temperature

Reduced tillage, including no-till, and crop rotation are common practices for corn (Zea mays L.) and soybean [Glycine max (L.) Merr.] production in the Midwest. Benefits of no-till vary with latitude and cropping system. This study was conducted to evaluate the influence of seasonal temperature and precipitation on the effects of primary tillage (plow, disk, chisel, subsoil, ridge-till, and no-till) and rotated and continuous corn and soybean production under rainfed conditions over 16 yr in southeastern Nebraska. Corn and soybean produced less grain with greater summer temperatures. Corn yield increased with less spring and more summer rainfall. Tillage and rotation practices affected corn grain yield; but only rotation affected soybean yield. Corn produced less grain with no-till than with plow. The tillage × year interaction was significant for both crops; the yield advantage for plow was less during seasons with warmer springs. Soybean grain yield was less responsive to favorable environments with the chisel than other tillage treatments. Grain yield was greater with rotation than continuous cropping for both corn (7.10 vs. 5.83 Mg ha−1) and soybean (2.57 vs. 2.35 Mg ha−1). The benefit of rotation in terms of grain yield was greatest for corn during years with cool springs. The benefit of rotation for soybean grain yield did not vary with weather conditions. Seasonal temperature and rainfall patterns influenced the effects of tillage and rotation on corn yield. In contrast, for soybean, only the pattern of temperature influenced the effect of tillage on yield.

Resistance status of house flies (Diptera: Muscidae) from southeastern Nebraska beef cattle feedlots to selected insecticides.

The status of resistance to three insecticides (permethrin, stirofos, and methoxychlor), relative to a laboratory-susceptible colony, was evaluated in field populations of house flies, Musca domestica L., collected from two beef cattle feedlots in southeastern Nebraska. Topical application and residual exposure to treated glass surfaces were suitable methods for determining the resistance status of house flies to permethrin, stirofos, or methoxychlor. However, in most cases, residual exposure was more sensitive in resistance detection (i.e., higher resistance ratios). The field populations tested were moderately resistant to permethrin (RR = 4.9-fold and RR = 7.3-fold, for topical application and residual exposure, respectively) and extremely resistant to stirofos and methoxychlor (not accurately quantifiable because of low mortality at the highest possible concentrations or doses). Probable explanations for the resistance status of these house fly populations and implications for global feedlot fly management are discussed.

Resistance Status of House Flies (Diptera: Muscidae) from Southeastern Nebraska Beef Cattle Feedlots to Selected Insecticides

Resistance Status of House Flies (Diptera: Muscidae) from Southeastern Nebraska Beef Cattle Feedlots to Selected Insecticides

Leary Site Revisited: Oneota and Central Plains Tradition Occupation along the Lower Missouri

Archaeologists of the central Plains and prairie peninsula have known of the Leary site (25RH1) in extreme southeastern Nebraska for more than 85 years. Early archaeological visitors to the site concluded that its remains were distinctly different than those from more common Central Plains tradition sites in the region. Instead, the Leary ceramics compare favorably with those from Oneota sites typically found to the east. The apparent anomalous position of this Oneota settlement in the central Plains indicates trans-Missouri movement of Oneota peoples into the eastern Plains. Leary is significant for the clues it holds regarding overall Oneota expansion during the Late Prehistoric period, as well as possible cultural interaction with Plains populations. The latter is especially relevant due to the fact that archaeological remains of the Central Plains tradition are also present at the Leary site. Analysis of curated assemblages collected during 1935 and 1965 suggests multiple Central Plains tradition occupations bracketing or overlapping those associated with the Oneota tradition. This and other finds at the Leary site raise interesting research questions to be addressed through future archaeological studies.

Eimeria lancasterensis and Eimeria ontarioensis from Fox Squirrels, Sciurus niger, in Southeastern Nebraska, U.S.A.

Abstract Eimeria lancasterensis Joseph, 1969, and Eimeria ontarioensis Lee and Dorney, 1971, are reported for the first time from the feces of fox squirrels, Sciurus niger, in southeastern Nebraska. Eimeria lancasterensis was found in 30 of 31 (97%) of the fox squirrels, and E. ontarioensis was found as a coinfection in 2 of 31 (6%). Oocyst measurements and structural features were similar to those reported previously from S. niger and the eastern grey squirrel, S. carolinensis.

THE INFORMATION-THEORETIC APPROACH TO MODEL SELECTION: DESCRIPTION AND CASE STUDY

In the wildlife literature there has been some recent criticism of statistical significance testing. In the past few years, both the Journal of ·Wildlife Management and the Wildlife Society Bulletin have published articles criticizing the overuse and misuse of hypothesis tests. One alternative to using hypothesis tests for model selection is the information-theoretic approach, proposed by Burnham and Anderson (1998). This technique uses values such as the Akaike Information Criterion and others to choose a set of plausible models from a set of a prioTi candidate models. Inferences are based on the set of plausible models, rather than on a single selected best model, and model-averaged point estimates of parameters may be used for prediction. The Burnham and Anderson method is gaining popularity in the wildlife science community, and statisticians who work with wildlife scientists should be aware of this analysis technique and how to use it properly. This paper will introduce statisticians to the information-theoretic approach to model selection and the statistical theory underlying it, as well as demonstrate the technique using data on bird species richness and abundance in riparian areas in southeastern Nebraska.

Watershed monitoring to address contamination source issues and remediation of the contaminant impairments

The Big Blue River Basin is located in southeastern Nebraska and northeastern Kansas and consists of surface water in the Big Blue River, Little Blue River, Black Vermillion River, and various tributaries draining 24,968 km2. Approximately 75% of the land area in the basin are cultivated cropland. The Big Blue River flows into Tuttle Creek Reservoir near Manhattan, Kansas. Releases from the lake are used to maintain streamflow in the Kansas River during low flow periods, contributing 27% of the mean flow rate of the Kansas River at its confluence with the Missouri River. Tuttle Creek Reservoir and the Kansas River are used as sources of public drinking water and meet many of the municipal drinking water supply needs of the urban population in Kansas from Junction City to Kansas City. Elevated concentrations of pesticides in the Big Blue River Basin are of growing concern in Kansas and Nebraska as concentrations may be exceeding public drinking water standards and water quality criteria for the protection of aquatic life. Pesticides cause significant problems for municipal water treatment plants in Kansas, as they are not appreciably removed during conventional water treatment processes unless activated carbon filtering is used. Pesticides have been detected during all months of the year with concentrations ranging up to 200 microg/l. If high concentration in water is associated with high flow conditions then large mass losses of pesticides can flow into the water supplies in this basin. This paper will investigate the use of a monitoring program to assess the non-point source of this atrazine contamination. Several practices will be examined that have shown ability to remediate or prevent these impairments.

Escherichia coli O157:H7 in free-ranging deer in Nebraska.

In order to determine the prevalence and distribution of the human pathogen, Escherichia coli O157:H7, in free-ranging deer, hunters were asked to collect and submit fecal samples from deer harvested during a regular firearm season (14-22 November 1998). Prior to the season, 47% of the hunters with permits in the southeastern Nebraska (USA) study area indicated a willingness to participate in the study. Approximately 25% of successful hunters in the area submitted deer fecal samples. Escherichia coli O157:H7 was cultured from four (0.25%) of 1,608 total samples submitted. All of the fecal samples that were properly identified (1,426) and all that were positive for E. coli O157:H7 were from white-tailed deer (Odocoileus virginianus). We were unable to detect a statistically significant geographic distribution pattern of E. coli O157:H7. The presence of E. coli O157:H7 in the feces of free-ranging deer has implications not only for hunters, consumers of venison, and others in contact with deer or deer feces, but also for the development of strategies aimed at reducing and/or controlling this pathogen in water sources and domestic livestock.