Whole Farm Economic Evaluation of No-Till Rice Production in Arkansas

Rice in Arkansas is typically produced using intensive tillage. No-till rice has been studied, but the research focus has been limited to impacts on yields and per acre net returns. This analysis evaluates the profitability of no-till rice at the whole-farm level using both enterprise budget analysis and linear programming.Crop Production/Industries,

Select \u3cem\u3eListeria monocytogenes\u3c/em\u3e Subtypes Commonly Found in Foods Carry Distinct Nonsense Mutations in \u3cem\u3einlA\u3c/em\u3e, Leading to Expression of Truncated and Secreted Internalin A, and Are Associated with a Reduced Invasion Phenotype for Human Intestinal Epithelial Cells

The surface protein internalin A (InlA) contributes to the invasion of human intestinal epithelial cells by Listeria monocytogenes. Screening of L. monocytogenes strains isolated from human clinical cases (n=46), foods (n=118), and healthy animals (n=58) in the United States revealed mutations in inlA leading to premature stop codons (PMSCs) in L. monocytogenes ribotypes DUP-1052A and DUP-16635A (PMSC mutation type 1), DUP-1025A and DUP-1031A (PMSC mutation type 2), and DUP-1046B and DUP-1062A (PMSC mutation type 3). While all DUP-1046B, DUP-1062A, DUP-16635A, and DUP-1031A isolates (n=76) contained inlA PMSCs, ribotypes DUP-1052A and DUP-1025A (n=72) contained isolates with and without inlA PMSCs. Western immunoblotting showed that all three inlA PMSCs result in the production of truncated and secreted InlA. Searches of the Pathogen Tracker database, which contains subtype and source information for more than 5,000 L. monocytogenes isolates, revealed that the six ribotypes shown to contain isolates with inlA PMSCs were overall more commonly isolated from foods than from human listeriosis cases. L. monocytogenes strains carrying inlA PMSCs also showed significantly (P=0.0004) reduced invasion of Caco-2 cells compared to isolates with homologous 3\u27 inlA sequences without PMSCs. Invasion assays with an isogenic PMSC mutant further supported the observation that inlA PMSCs lead to reduced invasion of Caco-2 cells. Our data show that specific L. monocytogenes subtypes which are common among U.S. food isolates but rare among human listeriosis isolates carry inlA mutations that are associated with, and possibly at least partially responsible for, an attenuated invasion phenotype

Enhancing Learning through Assessment: Case Study using feedback from a Human Dimension Survey

The Department of Wildlife and Fisheries Sciences at Texas A&M University is in the process of developing an assessment plan for measuring and evaluating each academic degree program (including student learning outcomes) in order to achieve objectives for institutional effectiveness. Assessment is a necessary component of any truly dynamic and progressive educational program. Assessment by evaluation can enhance student learning as well as augment instruction given by the professor. It also allows professors to determine which students reach or exceed learning targets and inform them so students can work to improve their weaknesses. Because there is no assessment plan currently in place for Texas A and M University's Department of Wildlife and Fisheries Sciences, I evaluated results from a previously developed survey that had been given in multiple years to students enrolled in Wildlife Conservation and Management (WFSC 201), an entrance level course of the department. In 2008 I administered the survey to students enrolled in WFSC 201 and to senior-level students enrolled in Conservation Biology and Wildlife Habitat Management (WFSC 406), an upper level course, to evaluate undergraduate students' beliefs on various wildlife issues, interest in animals, and knowledge status of endangered species. The research presented in this thesis contributes a general overview of assessment as it relates to undergraduate degree programs in wildlife and fisheries sciences. The focus was in particular to the evaluation of student conservation issues, animal interest, and species knowledge as it relates to student background (student classification, gender, hometown population size, and participation in youth groups. The results from analyses of responses to specific questions from a survey administered to undergraduates in the Department of Wildlife and Fisheries Sciences at Texas A&M University suggest that conservation beliefs and animal interest were highly correlated with gender and hometown population size. Students responding as males and having small hometown population size were more concerned about issues related to land or wildlife usage by humans and students responding as females and having large hometown population sizes were more concerned about issues related to habitat degradation and species viability. Males were also interested in mostly game species and females were interested in those of conservation, domestic, and herptiles. Lastly, the results from the knowledge question suggest that males attain and retain more knowledge of endangered species over females, and this relationship remains the same in non seniors and seniors. These results should be useful to the faculty currently and in the future as they develop an effective departmental assessment plan for the Department of Wildlife and Fisheries Sciences at Texas A&M University

Production Systems Involving Stocker Cattle and Soft Red Winter Wheat

A three year study at the Livestock and Forestry Research Station near Batesville, Arkansas evaluated production systems involving stocker cattle and soft red winter wheat. Grazing of soft red winter wheat forage from October through February followed by harvesting wheat grain or grazing through April with stocker cattle offers an alternative to conventional farming. Soft red winter wheat, when planted by September 15, produces an ample supply of high-quality forage that supports rapid growth of stocker cattle during October through April. Net income from stocker cattle averaged over $100 per acre. A normal wheat grain crop can also be harvested. These alternative production systems could increase the agricultural income by over$75,000,000 per year if 750,000 acres of wheat are grazed

Identification of Select Fumonisin Forming Fusarium Species Using PCR Applications of the Polyketide Synthase Gene and its Relationship to Fumonisin Production in vitro

A polymerase chain reaction (PCR) based diagnostic assay was used to develop markers for detection of Fusarium verticillioides (=F. moniliforme), a fumonisin producing fungus in maize tissues. Species-specific primers were designed based on sequence data from the polyketide synthase (PKS) gene (FUM1- previously FUM5) responsible for fumonisin production in fungi. Four sets of oligonucleotide primers were tested for their specificity using 24 strains of F. verticillioides, 10 F. proliferatum, and 12 of other Fusarium species. In addition, 13 species of other fungal genera, from four phyla, were tested as negative controls. Among the four sets, primer set B consistently amplified a 419-bp fragment from the DNA 96% of all F. verticillioides strains and 83% of F. proliferatum. All other fungi tested were negative using primer set B. A total of 38% of the F. verticillioides strains grown on a selective liquid medium produced fumonisin and 92% formed the toxin on standard rice medium. When fumonisin formed in culture, PCR assay using primer set B detected every strain of F. verticillioides, but only amplified 80% of F. proliferatum strains that produced the toxin. PCR detection was consistent at 100 pg/μl concentration of genomic DNA from 4 F. verticillioides strains, but varied at 10 pg/μl. Two duplicate greenhouse tests using artificially inoculated maize plants, had greater levels of F. verticillioides detected after re-evaluting using primer set B than from culturing of the tissues. The molecular protocols described in this study requires only 1 day for completion compared to approximately 10 days for cultural work and morphological determination. In conclusion, conventional PCR assay using primer set B provides a sensitive and accurate detection assay that can be used as a primary or secondary confirmation method for identification and occurrence of F. verticillioides within the maize tissues. However, studies using primer set B for fumonisin production determined by strains of F. verticillioides and F. proliferatum will require further verification

Preparation and Preliminary Dielectric Characterization of Structured C\u3csub\u3e60\u3c/sub\u3e-Thiol-Ene Polymer Nanocomposites Assembled Using the Thiol-Ene Click Reaction

Fullerene-containing materials have the ability to store and release electrical energy. Therefore, fullerenes may ultimately find use in high-voltage equipment devices or as super capacitors for high electric energy storage due to this ease of manipulating their excellent dielectric properties and their high volume resistivity. A series of structured fullerene (C60) polymer nanocomposites were assembled using the thiol-ene click reaction, between alkyl thiols and allyl functionalized C60 derivatives. The resulting high-density C60-urethane-thiol-ene (C60-Thiol-Ene) networks possessed excellent mechanical properties. These novel networks were characterized using standard techniques, including infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA), and thermal gravimetric analysis (TGA). The dielectric spectra for the prepared samples were determined over a broad frequency range at room temperature using a broadband dielectric spectrometer and a semiconductor characterization system. The changes in thermo-mechanical and electrical properties of these novel fullerene-thiol-ene composite films were measured as a function of the C60 content, and samples characterized by high dielectric permittivity and low dielectric loss were produced. In this process, variations in chemical composition of the networks were correlated to performance characteristics

Maternal Exposure to Occupational Asthmagens During Pregnancy and Autism Spectrum Disorder in the Study to Explore Early Development

Abstract Maternal immune activity has been linked to children with autism spectrum disorder (ASD). We examined maternal occupational exposure to asthma-causing agents during pregnancy in relation to ASD risk. Our sample included 463 ASD cases and 710 general population controls from the Study to Explore Early Development whose mothers reported at least one job during pregnancy. Asthmagen exposure was estimated from a published job-exposure matrix. The adjusted odds ratio for ASD comparing asthmagen-exposed to unexposed was 1.39 (95 % CI 0.96–2.02). Maternal workplace asthmagen exposure was not associated with ASD risk in this study, but this result does not exclude some involvement of maternal exposure to asthma-causing agents in ASD

Apospory and Diplospory in Diploid Boechera (Brassicaceae) May Facilitate Speciation by Recombination-Driven Apomixis-to-Sex Reversals

Apomixis (asexual seed formation) in angiosperms occurs either sporophytically, through adventitious embryony, or gametophytically, where an unreduced female gametophyte (embryo sac) forms and produces an unreduced egg that develops into an embryo parthenogenetically. Multiple types of gametophytic apomixis occur, and these are differentiated based on where and when the unreduced gametophyte forms, a process referred to as apomeiosis. Apomeiotic gametophytes form directly from ameiotic megasporocytes, as in Antennaria-type diplospory, from unreduced spores derived from 1st division meiotic restitutions, as in Taraxacum-type diplospory, or from cells of the ovule wall, as in Hieracium-type apospory. Multiple types of apomeiosis occasionally occur in the same plant, which suggests that the different types occur in response to temporal and/or spatial shifts in termination of sexual processes and onset timing of apomeiosis processes. To better understand the origins and evolutionary implications of apomixis in Boechera (Brassicaceae), we determined apomeiosis type for 64 accessions representing 44 taxonomic units. Plants expressing apospory and diplospory were equally common, and these generally produced reduced and unreduced pollen, respectively. Apospory and diplospory occurred simultaneously in individual plants of seven taxa. In Boechera, apomixis perpetuates otherwise sterile or semisterile interspecific hybrids (allodiploids) through multiple generations. Accordingly, ample time, in these multigenerational clones, is available for rare meioses to produce haploid, intergenomically recombined male and female gametes. The fusion of such gametes could then produce segmentally autoploidized progeny. If sex re-emerges among such progeny, then new and genomically unique sexual species could evolve. Herein, we present evidence that such apomixis-facilitated speciation is occurring in Boechera, and we hypothesize that it might also be occurring in facultatively apomictic allodiploids of other angiospermous taxa

Subclinical Vascular Disease Burden and Premature Mortality Among Middle-aged Adults: the Atherosclerosis Risk in Communities Study

Background: Whether high burden of subclinical vascular disease (SVD) is associated with increased premature mortality among middle-aged adults is not adequately understood. The association of midlife SVD burden with premature mortality among middle-aged adults free of clinical cardiovascular disease (CVD) could provide further insights into stratifying premature death beyond clinical CVD. Objective: To determine whether high burden of subclinical vascular disease is associated with increased premature mortality among middle-aged adults. Design: We leveraged data from the Atherosclerosis Risk in Communities Study. Participants: Thirteen thousand eight hundred seventy-six community-dwelling blacks and whites aged 45–64 years from the Atherosclerosis Risk in Communities Study. Main Measures: Each SVD measure—ankle-brachial index, carotid intima-media thickness, and electrocardiogram—was scored 0 (no abnormalities), 1 (minor abnormalities), or 2 (major abnormalities). An index was constructed as the sum of three measures, ranging from 0 (lowest burden) to 6 (highest burden). We used the Cox proportional-hazards model to determine the association of SVD burden with premature mortality (death before age 70) among persons free of clinical CVD. We then tested the difference in point estimates between SVD and clinical CVD. Key Results: Among persons without CVD, the premature death was 1.7, 2.1, 2.5, and 3.8 per 1000 person-years among those with an SVD score of 0 (lowest burden), 1, 2, and 3–6 (highest burden), respectively. After multivariable-adjustment, highest SVD burden (score = 3–6; HR = 1.47) was significantly associated with premature death among persons initially without CVD. In the model where persons with and without CVD were included, high SVD burden (score: 3–6 vs. 0) and CVD did not have hugely different association with premature death (HR = 1.49 vs. 1.68; P = 0.32 for comparison). Conclusions: Midlife SVD burden was associated with premature mortality and it could stratify premature death beyond clinical CVD. It is important to take SVD into account when designing interventions for reducing premature mortality