Sum divisor cordial labeling in the context of graphs operations on bistar

A sum divisor cordial labeling of a graph G with vertex set V (G) is a bijection f : V (G) → {1, 2, 3, . . . , |V (G)|} such that an edge e = uv is assigned the label 1 if2|[f(u)+f(v)] and 0 otherwise, then the number of edges labeled with 0 and the number of edges labeled with 1 differ by at most 1. If a graph admits a sum divisor cordial labeling, then it is called sum divisor cordial graph. In this paper we prove that bistar Bm,n, splitting graph of bistar Bm,n, degree splitting graph of bistar Bm,n, shadow graph of bistar Bm,n, restricted square graph of bistar Bm,n, barycentric subdivision of bistar Bm,n and corona product of bistar Bm,n with K₁ admit sum divisor cordial labeling.Publisher's Versio

Impacts of the Food Safety Modernization Act on On-Farm Food Safety Practices for Small and Sustainable Produce Growers

We use data from a national survey of fruit and vegetable growers to examine the current prevalence and cost burden of food safety practices required in the proposed Produce Rule implementing the Food Safety Modernization Act. In particular, we analyze the influence of farm size and farming practices on the probability of adopting food safety measures that would be required by the Produce Rule; and we analyze how the costs of using those food safety practices vary by farm size and farm practices. Majorities of our respondents currently employ most of the food safety practices that would be required under the proposed Produce Rule, but a large number of growers will nonetheless face significant changes to meet the Rule’s requirements. We do not find any effect of farm size on the probability of using food safety measures, but we find that food safety costs significant economies of scale. Sustainable farming practices are negatively correlated with the probability of testing and conducting field inspections, and they are associated with increased costs for testing and sampling, harvest container sanitation, and written records relative to conventional growers. While our estimates indicate that small and sustainable growers would face more significant changes and more burdensome costs to comply with the proposed Produce Rule, in our sample most of them would ultimately be exempt from the rule either based on farm size or the Tester-Hagan exemption

Harnessing Wastewater for Renewable Energy (2013-2)

This case study explores the options for using wastewater to produce renewable energy in the context of a public wastewater treatment plant. It provides an opportunity for students to synthesize knowledge from resource economics, engineering, environmental science, agriculture, and public policy to develop a transdisciplinary approach to a socio-environmental issue. The case is designed for upper division undergraduate courses in resource economics or environmental engineering, but several modifications are provided graduate course applications. Students assume the role of a newly hired analyst at a consulting firm in Washington, DC, that specializes in renewable energy solutions. They are charged with proposing a system that uses wastewater to produce energy, while accounting for multiple constraints across disciplines. Students are provided with economic, political, environmental, and engineering data on four different solid waste disposal options and work in small groups to develop a proposed solution that balances these factors. They present and justify their suggested solutions in small-group presentations, and the case concludes with an instructor-led discussion of the relevant considerations

Military Magic or Nature’s Fool

f this world lasts for a million years or two million “Iyears, or more, never can you exhaust the subject matter of humanity and nature, ” said Charles Burchfield regarding his source of inspiration. “I don’t know how much time I’ve got left, but I’d like to have at least another lifetime … to say what I want to say about nature. ” This fascination began during the artist’s childhood in Salem, Ohio, where he “formed the habit of wandering off to the woods and fields … in search of wild flowers in the spring or colored leaves in the fall. ” These, along with blossoming trees and all manner of plants, made up his earliest drawings, also described in copious journals, more than 10,000 pages. “I hereby dedicate my life and soul to the study and love of nature, with the purpose to bring it before the mass of uninterested public.” Burchfield’s art education began at the Cleveland School of Art, where he became familiar with the teachings of artist and philosopher Arthur Wesley Dow who, ahead of his time, believed that nature should be depicted not in realistic terms but in a harmonious presentation of compositional elements (line, color, light and dark). During these years, Burchfield absorbed such diverse influences as Chinese scroll paintings; the works of Hiroshige, Hokusai, and Aubrey Beardsley; and Russian ballet designs by Léon Bakst. But “The greatest inspiration to me was Henry G. Keller … not only a good painter but also a good teacher…. He made you feel as though art was the most important thing in the world, and you couldn’t do better than to be an artist if you had the aptitude for it. ” Keller said that his Author affi liation: Centers for Disease Control and Prevention

Clostridium difficile: moving beyond antimicrobial therapy

Background\ud New therapies are needed to manage the increasing incidence, severity, and high rate of recurrence of Clostridium difficile infection.\ud \ud Methods\ud Objective\ud To assess the ability of monoclonal antibodies directed against two toxins of C.difficile to prevent recurrence of disease.\ud \ud Design\ud Randomized, double-blind, placebo-controlled study\ud \ud Setting\ud 30 medical centers in the United States and Canada\ud \ud Subjects\ud 200 subjects with diarrhea and a positive stool toxin assay for C.difficile being treating with metronidazole or vancomycin\ud \ud Intervention\ud Antibodies administered together as a single infusion, each at a dose of 10 mg per kilogram of body weight\ud \ud Outcomes\ud The primary outcome was laboratory-documented recurrence of infection during the 84 days after the administration of monoclonal antibodies or placebo.\ud \ud Results\ud Among the 200 patients who were enrolled (101 in the antibody group and 99 in the placebo group), the rate of recurrence of C. difficile infection was lower among patients treated with monoclonal antibodies (7% vs. 25%; 95% confidence interval, 7 to 29; P < 0.001). The absolute risk reduction (ARR) was 16%, yielded a number needed to treat (NNT) of 5.5. The recurrence rates among patients with the epidemic BI/NAP1/027 strain were 8% for the antibody group and 32% for the placebo group (P = 0.06); among patients with more than one previous episode of C. difficile infection, recurrence rates were 7% and 38%, respectively (P = 0.006). The mean duration of the initial hospitalization for inpatients did not differ significantly between the antibody and placebo groups (9.5 and 9.4 days, respectively). At least one serious adverse event was reported by 18 patients in the antibody group and by 28 patients in the placebo group (P = 0.09).\ud \ud Conclusions\ud The addition of monoclonal antibodies against C. difficile toxins to antibiotic agents significantly reduced the recurrence of C. difficile infection. (ClinicalTrials.gov number, NCT00350298 [ClinicalTrials.gov].

Development of phosphate glass-polymer blends

A novel class of organic-inorganic polymer hybrids was developed by melt-blending up to 50 (v/v)%[about 83 (w/w)%] tin-based polyphosphate glass (Pglass) and organic thermoplastic polymers in conventional plastics processing equipment. The melt rheology of the pure Pglass and of the polymer hybrids was studied under oscillatory shear flow and deformation to understand the behavior of these materials and to accelerate efforts to melt process the Pglass with organic polymers. All the materials were found to be linearly viscoelastic in the range of temperature and frequencies examined and their viscoelastic functions increased with increasing Pglass concentration. The Pglass significantly enhanced the shear-thinning characteristics of the Pglass-LDPE hybrid, indicating the presence of nonlinear chemical and physical interactions between the hybrid components. Morphological examination of the materials by scanning electron microscopy revealed interesting evolution of microstructure of the Pglass phase from droplets (or round beads)to elongated and interpenetrating network structures as the glass concentration was increased in the Pglass-LDPE hybrids. Melt viscosities of the hybrid materials were well described by a simple power-law equation and a Maxwellian (Hookean model with three relaxation times. The melt viscosity of the pure Pglass was modeled by a modified Rouse model with two relaxation times. The complex viscosity of the Pglass, and the polymer hybrids at different temperatues and frequencies can be superposed and described by an Arrhenius-type relation, enabling calculation of the flow-activation energies (25-285 kJ/mol) for the materials. The beneficial function of the Pglass in the hybrid system was significantly enhanced by pre-treating the glass with coupling agents prior to incorporating them into the Pglass-LDPE hybrids. The creep and recovery behavior of these polymer hybrids at 300C were studied to understand the effect of the Pglass on the creep resistance of the LDPE. The results suggest that the Pglass acts as a reinforcement and increased Pglass loading leads to significantly lower creep strains. This creep resistance is further enhanced by pre-treating the Pglass with coupling agents prior to incorporating them into the Pglass-LDPE hybrids. The experimental creep compliance of these materials is compared to an empirical power-law equation and a modified Burgers\u27 model. The models successfully predict the creep behavior, suggesting that the materials are linearly viscoelastic under the test conditions

ESSAYS ON QUALITY CERTIFICATION IN FOOD AND AGRICULTURAL MARKETS

This dissertation features three essays exploring the market impacts of two types of quality certification---a voluntary non-GMO label and a mandatory food safety standard. In the first essay, I use a hedonic framework to examine whether firms use a voluntary quality certification for non-GMO products to extract rent from customers. Using U.S. retail scanner data coupled with data from a voluntary non-GMO label, I find no evidence of price premiums or quantity changes for newly certified non-GMO products. Instead, the label may induce firms to develop new non-GMO products targeted to high-valuation consumers. The second essay examines how voluntary non-GMO food labeling impacts demand in the ready-to-eat [RTE] cereal industry. I estimate a discrete-choice, random coefficients logit demand model using monthly data for 50 cereal brands across 100 DMAs. Consumer tastes for the label are widely distributed, and this heterogeneity plays a substantial role in individual choices; but, on average, the non-GMO label has a positive impact on demand. I estimate welfare effects by simulating two labeling scenarios: one in which all brands use the non-GMO label, and one in which no brands use the label. The simulation results suggest that non-GMO labeling in the RTE cereal industry may improve consumer welfare on average. In the final essay, we use data from an original national survey of produce growers to examine whether complying with the Food Safety Modernization Act's Produce Rule will be prohibitively costly for some growers. We examine how food safety measure expenditures required by the Rule vary with farm size and practices using a double hurdle model to control for selectivity in using food safety practices and reporting expenditures. Expenditures per acre decrease with farm size, and growers using sustainable farming practices spend more than conventional growers on many food safety practices. We use our estimates to quantify how the cost burden of compliance varies with farm size. We also explore the policy implications of exemptions to the Rule by simulating how changes to exemption thresholds might affect the cost burden of each food safety practice on farms at the threshold

Adoption and Coexistence of GE, Conventional non-GE, and Organic Crops

The adoption of genetically engineered (GE) crop varieties by U.S. farmers is widespread for major crops—94 percent of planted acres for soybeans, and 88 percent for corn in 2012 (USDA-NASS 2012). The potential exists for GE crop production to impose costs on organic and conventional non-GE production via unintended presence of GE material along the supply chain through: • Contamination of seed stock • Accidental cross-pollination • Accidental co-mingling during planting, harvesting, handling, and storing of crops (Bullock and Desquilbet 2002). Maintaining the integrity of GE-differentiated product markets relies on segregation protocols such as: • Hybrid selection and seed purity testing • Physical distancing during crop production • Equipment cleaning and product segregation during processing • GE-testing (Greene and Smith 2010)

Effect of Market Channel, Farm Scale, and Years in Production on Mid-Atlantic Vegetable Producers\u27 Knowledge and Implementation of Good Agricultural Practices

Foodborne illnesses associated with fresh produce have dramatically increased within the last decade. Good Agricultural Practices (GAP) were developed to address potential sources of pre-harvest microbial contamination, but certification remains low. The majority of mid-Atlantic vegetable farms are fresh market, but limited information is available about what on-farm production practices are being utilized to mitigate food safety risks. Our goal was to assess Maryland and Delaware vegetable producers\u27 understanding and implementation of GAP. An electronic survey on pre-harvest production practices was administered at commercial grower meetings in 2010 and 2013. A total of 313 surveys were analyzed, and Probit regression was used to estimate the average marginal effects of farm scale, years in production and market channel on the probability of using different on-farm food safety practices. Generally, food safety practices did not differ across farm scale or years in production. However, market channel did influence a grower\u27s decision to implement some food safety practices. Growers who marketed their produce primarily through wholesale channels were more likely to: have written policies for how they grew and handled their produce, test their irrigation water at least once a year for microbial contamination, or be GAP-certified. Economic constraints were not reported as the primary obstacle for GAP implementation in either survey. While more research is needed to better understand how market channel influences decision-making activities including on-farm food safety practices, this study highlights the complexity of the issue and the need for GAP educational programs to expand beyond a one-size-fits-all approach