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Midwestern United States (midwestern + united_states)
Selected AbstractsAbundance of six tetracycline resistance genes in wastewater lagoons at cattle feedlots with different antibiotic use strategiesENVIRONMENTAL MICROBIOLOGY, Issue 1 2007Nicholas Peak Summary The abundance of six tetracycline resistance genes tet(O), tet(Q), tet(W), tet(M), tet(B) and tet(L), were quantified over time in wastewater lagoons at concentrated animal feeding operations (CAFO) to assess how feedlot operation affects resistance genes in downstream surface waters. Eight lagoons at five cattle feedlots in the Midwestern United States were monitored for 6 months. Resistance and 16S-rRNA gene abundances were quantified using real-time PCR, and physicochemical lagoon conditions, tetracycline levels, and other factors (e.g. feedlot size and weather conditions) were monitored over time. Lagoons were sorted according to antibiotic use practice at each site, and designated as ,no-use', ,mixed-use' or ,high-use' for comparison. High-use lagoons had significantly higher detected resistance gene levels (tetR; 2.8 × 106 copies ml,1) relative to no-use lagoons (5.1 × 103 copies ml,1; P < 0.01) and mixed-use lagoons (7.3 × 105 copies ml,1; P = 0.076). Bivariate correlation analysis on pooled data (n = 54) confirmed that tetR level strongly correlated with feedlot area (r = 0.67, P < 0.01) and ,total' bacterial 16S-rRNA gene level in each lagoon (r = 0.51, P < 0.01), which are both characteristic of large CAFOs. tet(M) was the most commonly detected gene, both in absolute number and normalized to 16S-rRNA gene level, although tet(O), tet(Q) and tet(W) levels were also high in the mixed and high-use lagoons. Finally, resistance gene levels were highly seasonal with abundances being 10,100 times greater in the autumn versus the summer. Results show that antibiotic use strategy strongly affects both the abundance and seasonal distribution of resistance genes in associated lagoons, which has implications on water quality and feedlot management practices. [source] The effect of land use on dissolved organic carbon and nitrogen uptake in streamsFRESHWATER BIOLOGY, Issue 11 2009LAURA T. JOHNSON Summary 1. Agricultural and urban land use may increase dissolved inorganic nitrogen (DIN) concentrations in streams and saturate biotic nutrient demand, but less is known about their impacts on the cycling of organic nutrients. To assess these impacts we compared the uptake of DIN (as ammonium, NH4+), dissolved organic carbon (DOC, as acetate), and dissolved organic nitrogen (DON, as glycine) in 18 low-gradient headwater streams in southwest Michigan draining forested, agricultural, or urban land-use types. Over 3 years, we quantified uptake in two streams in each of the three land-use types during three seasons (spring, summer and autumn). 2. We found significantly higher NH4+ demand (expressed as uptake velocity, Vf) in urban compared to forested streams and NH4+Vf was greater in spring compared to summer and autumn. Acetate Vf was significantly higher than NH4+ and glycine Vf, but neither acetate nor glycine Vf were influenced by land-use type or season. 3. We examined the interaction between NH4+ and acetate demand by comparing simultaneous short-term releases of both solutes to releases of each solute individually. Acetate Vf did not change during the simultaneous release with NH4+, but NH4+Vf was significantly higher with increased acetate. Thus, labile DOC Vf was not limited by the availability of NH4+, but NH4+Vf was limited by the availability of labile DOC. In contrast, neither glycine nor NH4+Vf changed when released simultaneously indicating either that overall N-uptake was saturated or that glycine and NH4+ uptake were controlled by different factors. 4. Our results suggest that labile DOC and DON uptake can be equivalent to, or even higher than NH4+ uptake, a solute known to be highly bioreactive, but unlike NH4+ uptake, may not differ among land-use types and seasons. Moreover, downstream export of nitrogen may be exacerbated by limitation of NH4+ uptake by the availability of labile DOC in headwater streams from the agricultural Midwestern United States. Further research is needed to identify the factors that influence cycling of DOC and DON in streams. [source] An integrated biogeochemical and economic analysis of bioenergy crops in the Midwestern United StatesGCB BIOENERGY, Issue 5 2010ATUL K. JAIN Abstract This study integrates a biophysical model with a county-specific economic analysis of breakeven prices of bioenergy crop production to assess the biophysical and economic potential of biofuel production in the Midwestern United States. The bioenergy crops considered in this study include a genotype of Miscanthus, Miscanthus×giganteus, and the Cave-in-Rock breed of switchgrass (Panicum virgatum). The estimated average peak biomass yield for miscanthus in the Midwestern states ranges between 7 and 48 metric tons dry matter per hectare per year ( t DM ha,1 yr,1), while that for switchgrass is between 10 and 16 t DM ha,1 yr,1. With the exception of Minnesota and Wisconsin, where miscanthus yields are likely to be low due to cold soil temperatures, the yield of miscanthus is on average more than two times higher than yield of switchgrass. We find that the breakeven price, which includes the cost of producing the crop and the opportunity cost of land, of producing miscanthus ranges from $53 t,1 DM in Missouri to $153 t,1 DM in Minnesota in the low-cost scenario. Corresponding costs for switchgrass are $88 t,1 DM in Missouri to $144 t,1 DM in Minnesota. In the high-cost scenario, the lowest cost for miscanthus is $85 t,1 DM and for switchgrass is $118 t,1 DM, both in Missouri. These two scenarios differ in their assumptions about ease of establishing the perennial crops, nutrient requirements and harvesting costs and losses. The differences in the breakeven prices across states and across crops are mainly driven by bioenergy and row crop yields per hectare. Our results suggest that while high yields per unit of land of bioenergy crops are critical for the competitiveness of bioenergy feedstocks, the yields of the row crops they seek to displace are also an important consideration. Even high yielding crops, such as miscanthus, are likely to be economically attractive only in some locations in the Midwest given the high yields of corn and soybean in the region. [source] Conceptualization and assessment of disengagement in romantic relationshipsPERSONAL RELATIONSHIPS, Issue 3 2008ROBIN A. BARRY Research examining relationship distress and dissolution highlights the importance of romantic disengagement. Nevertheless, prior conceptualizations and measures of romantic disengagement have tended to combine disengagement with related but distinct constructs hindering the study of romantic disengagement. The present research used exploratory and confirmatory factor analyses to clarify the conceptualization of romantic disengagement and to develop a novel measure,the Romantic Disengagement Scale (RDS). The RDS demonstrated adequate fit across samples of dating individuals (n = 203), married couples (n = 77), and women in physically aggressive relationships (n = 42) from the Midwestern United States. The RDS also demonstrated strong divergent and incremental validity. The discussion focuses on implications for enhancing conceptual models, research methodology, and clinical interventions. [source] Will climate change be beneficial or detrimental to the invasive swede midge in North America?GLOBAL CHANGE BIOLOGY, Issue 8 2008Contrasting predictions using climate projections from different general circulation models Abstract Climate change may dramatically affect the distribution and abundance of organisms. With the world's population size expected to increase significantly during the next 100 years, we need to know how climate change might impact our food production systems. In particular, we need estimates of how future climate might alter the distribution of agricultural pests. We used the climate projections from two general circulation models (GCMs) of global climate, the Canadian Centre for Climate Modelling and Analysis GCM (CGCM2) and the Hadley Centre model (HadCM3), for the A2 and B2 scenarios from the Special Report on Emissions Scenarios in conjunction with a previously published bioclimatic envelope model (BEM) to predict the potential changes in distribution and abundance of the swede midge, Contarinia nasturtii, in North America. The BEM in conjunction with either GCM predicted that C. nasturtii would spread from its current initial invasion in southern Ontario and northwestern New York State into the Canadian prairies, northern Canada, and midwestern United States, but the magnitude of risk depended strongly on the GCM and the scenario used. When the CGCM2 projections were used, the BEM predicted an extensive shift in the location of the midges' climatic envelope through most of Ontario, Quebec, and the maritime and prairie provinces by the 2080s. In the United States, C. nasturtii was predicted to spread to all the Great Lake states, into midwestern states as far south as Colorado, and west into Washington State. When the HadCM3 was applied, southern Ontario, Saskatchewan, and Washington State were not as favourable for C. nasturtii by the 2080s. Indeed, when used with the HadCM3 climate projections, the BEM predicted the virtual disappearance of ,very favourable' regions for C. nasturtii. The CGCM2 projections generally caused the BEM to predict a small increase in the mean number of midge generations throughout the course of the century, whereas, the HadCM3 projections resulted in roughly the same mean number of generations but decreased variance. Predictions of the likely potential of C. nasturtii spatial spread are thus strongly dependent on the source of climate projections. This study illustrates the importance of using multiple GCMs in combination with multiple scenarios when studying the potential for spatial spread of an organism in response to climate change. [source] The Effects of Mammographic Detection and Comorbidity on the Survival of Older Women with Breast CancerJOURNAL OF AMERICAN GERIATRICS SOCIETY, Issue 6 2002Carol P. McPherson MSW OBJECTIVES: To determine an upper age limit or quantifiable level of comorbidity that would render mammography screening ineffectual in decreasing mortality in women aged 65 and older. DESIGN: Retrospective cohort study. SETTING: Upper midwestern United States. PARTICIPANTS: Five thousand one hundred eighty-six predominantly Caucasian women aged 65 to 101 diagnosed with invasive breast cancer from 1986 through 1994. Data were obtained from The Upper Midwest Tumor Registry System, a regional consortium database in Minnesota, North Dakota, and South Dakota. MEASUREMENTS: Relative risks (RRs) of death were computed for patients with mammographically detected tumors, stratified by age and comorbidity. Survival analysis was performed, stratified by level of comorbidity and method of tumor detection. RESULTS: Patients with mammographically detected tumors and no comorbidity experienced significantly lower RRs of death in every age group (range P < .001 to P = .039). Women with mammographically detected tumors and mild to moderate comorbidity had RRs of death as follows: age 65 to 69 (RR = 0.32, 95% confidence interval (CI) = 0.15,0.69), age 70 to 74, (RR = 0.45, 95% CI = 0.22,0.91); age 75 to 79 (RR = 0.47, 95% CI = 0.25,0.88), age 80 and older (RR = 0.52, 95% CI = 0.33,0.80). Women with severe or multiple comorbidities experienced no improvement in survival with mammographically detected tumors. CONCLUSIONS: Mammographic detection of breast cancer may be associated with a significantly decreased risk of death for older women of all ages, even for women with mild to moderate levels of comorbidity, but for older women with severe or multiple comorbidities, mammography is not associated with improvement in overall survival. [source] Genetic Determination of Colles' Fracture and Differential Bone Mass in Women With and Without Colles' FractureJOURNAL OF BONE AND MINERAL RESEARCH, Issue 7 2000Hong-Wen Deng Abstract Osteoporotic fractures (OFs) are a major public health problem. Direct evidence of the importance and, particularly, the magnitude of genetic determination of OF per se is essentially nonexistent. Colles' fractures (CFs) are a common type of OF. In a metropolitan white female population in the midwestern United States, we found significant genetic determination of CF. The prevalence (K) of CF is, respectively, 11.8% (±SE 0.7%) in 2471 proband women aged 65.55 years (0.21), 4.4% (0.3%) in 3803 sisters of the probands, and 14.6% (0.7%) in their mothers. The recurrence risk (K0), the probability that a woman will suffer CF if her mother has suffered CF is 0.155 (0.017). The recurrence risk (Ks), the probability that a sister of a proband woman will suffer CF given that her proband sister has suffered CF is 0.084 (0.012). The relative risk , (the ratio of the recurrence risk to K), which measures the degree of genetic determination of complex diseases such as CF, is 1.312 (0.145; ,0) for a woman with an affected mother and 1.885 (0.276; ,s) for a woman with an affected sister. A ,-value significantly greater than 1.0 indicates genetic determination of CF. The terms ,0 and ,s are related to the genetic variances of CF. These parameters translate into a significant and moderately high heritability (0.254 [0.118]) for CF. These parameters were estimated by a maximum likelihood method that we developed, which provides a general tool for characterizing genetic determination of complex diseases. In addition, we found that women without CF had significantly higher bone mass (adjusted for important covariates such as age, weight, etc.) than women with CF. [source] Validation of A brief sense of community scale: Confirmation of the principal theory of sense of communityJOURNAL OF COMMUNITY PSYCHOLOGY, Issue 1 2008N. Andrew Peterson First-order and second-order models of sense of community (SOC) were tested using confirmatory factor analysis (CFA) of data gathered from a random sample of community residents (n=293) located in the midwestern United States. An 8-item Brief Sense of Community Scale (BSCS) was developed to represent the SOC dimensions of needs fulfillment, group membership, influence, and shared emotional connection. The CFA results for the BSCS supported both the scale's hypothesized first-order and second-order factor structure. The overall BSCS scale and its subscales were also found to be correlated as expected with community participation, psychological empowerment, mental health, and depression. Findings provide empirical support for the BSCS and its underlying multidimensional theory of SOC. Implications of the study are described and directions for future research discussed. © 2007 Wiley Periodicals, Inc. [source] How and why do college students use Wikipedia?JOURNAL OF THE AMERICAN SOCIETY FOR INFORMATION SCIENCE AND TECHNOLOGY, Issue 11 2009Sook Lim The purposes of this study were to explore college students' perceptions, uses of, and motivations for using Wikipedia, and to understand their information behavior concerning Wikipedia based on social cognitive theory (SCT). A Web survey was used to collect data in the spring of 2008. The study sample consisted of students from an introductory undergraduate course at a large public university in the midwestern United States. A total of 134 students participated in the study, resulting in a 32.8% response rate. The major findings of the study include the following: Approximately one-third of the students reported using Wikipedia for academic purposes. The students tended to use Wikipedia for quickly checking facts and finding background information. They had positive past experiences with Wikipedia; however, interestingly, their perceptions of its information quality were not correspondingly high. The level of their confidence in evaluating Wikipedia's information quality was, at most, moderate. Respondents' past experience with Wikipedia, their positive emotional state, their disposition to believe information in Wikipedia, and information utility were positively related to their outcome expectations of Wikipedia. However, among the factors affecting outcome expectations, only information utility and respondents' positive emotions toward Wikipedia were related to their use of it. Further, when all of the independent variables, including the mediator, outcome expectations, were considered, only the variable information utility was related to Wikipedia use, which may imply a limited applicability of SCT to understanding Wikipedia use. However, more empirical evidence is needed to determine the applicability of this theory to Wikipedia use. Finally, this study supports the knowledge value of Wikipedia (Fallis, 2008), despite students' cautious attitudes toward Wikipedia. The study suggests that educators and librarians need to provide better guidelines for using Wikipedia, rather than prohibiting Wikipedia use altogether. [source] Different seasons: Biological aging among the Mennonites of the midwestern United StatesAMERICAN JOURNAL OF HUMAN BIOLOGY, Issue 3 2002Brian Suarez No abstract is available for this article. [source] Regional Spatial Modeling of Topsoil GeochemistryBIOMETRICS, Issue 1 2009C. A. Calder Summary Geographic information about the levels of toxics in environmental media is commonly used in regional environmental health studies when direct measurements of personal exposure is limited or unavailable. In this article, we propose a statistical framework for analyzing the spatial distribution of topsoil geochemical properties, including the concentrations of various toxicants. Due to the small-scale heterogeneity of most geochemical topsoil processes, direct measurements of the processes themselves only provide highly localized information; it is thus financially prohibitive to study the spatial patterns of these processes across a large region using traditional geostatistical analyses of point-referenced topsoil data. Instead, it is standard practice to assess geochemical patterns at a regional scale using point-referenced measurements collected in stream sediment because, unlike topsoil data, individual stream sediment geochemical measurements are representative of the surrounding area. We propose a novel multiscale soils (MSS) model that formally synthesizes data collected in topsoil and stream sediment and allows the richer stream sediment information to inform about the topsoil process, which in environmental health studies is typically more relevant. Our model accommodates the small-scale heterogeneity of topsoil geochemical processes by modeling spatial dependence at an aggregate resolution corresponding to hydrologically similar regions known as watersheds. We present an analysis of the levels of arsenic, a toxic heavy metal, in topsoil across the midwestern United States using the MSS model and show that this model has better predictive abilities than alternative approaches using more conventional statistical models for point-referenced spatial data. [source] | ||||||||||||||||