1,260 research outputs found
Field Evaluations of Herbicides on Vegetable, Small Fruit, and Ornamental Crops, 2000, 2001, & 2002
Field evaluations of herbicides provide the chemical industry, governmental agencies, such as IR-4, and the Arkansas Agricultural Experiment Station with an evaluation of herbicide performance on small fruit, vegetable, and ornamental crops grown under Arkansas conditions. This report provides a means for disseminating information to interested private and public service weed scientists
Leading for Learning: Reflective Tools for School and District Leaders
Provides reflective ideas and tools for educators to enhance leadership in learning. Includes key ideas, real examples, and reflective questions that leaders can use can use to assess their organizations, enact strategic plans, and teach colleagues
Field Evaluation of Herbicides on Small Fruit, Vegetable, and Ornamental Crops, 1997
Growers generally use herbicides to efficiently produce high-quality fruit and vegetables for processing or fresh market sales. Due to the smaller acreage of these crops compared to major field crops, fewer herbicides are registered for use in fruit and vegetable crops than for field crops. Each year, new herbicides are evaluated under Arkansas growing conditions with the objective of improving the herbicide technology for the grower, processor, and ultimately the consumer. This report includes studies on the control of many of the more serious weed problems in important crops of this region, including snapbeans, spinach, southern pea, watermelon, cantaloupe, tomato, blackberry, and grape. In addition, the report includes information on the tolerance of selected bedding plants to some effective herbicides
Evaluating Simplistic Methods to Understand Current Distributions and Forecast Distribution Changes Under Climate Change Scenarios: An Example With Coypu (Myocastor coypus)
Invasive species provide a unique opportunity to evaluate factors controlling biogeographic distributions; we can consider introduction success as an experiment testing suitability of environmental conditions. Predicting potential distributions of spreading species is not easy, and forecasting potential distributions with changing climate is even more difficult. Using the globally invasive coypu (Myocastor coypus [Molina, 1782]), we evaluate and compare the utility of a simplistic ecophysiological based model and a correlative model to predict current and future distribution. The ecophysiological model was based on winter temperature relationships with nutria survival. We developed correlative statistical models using the Software for Assisted Habitat Modeling and biologically relevant climate data with a global extent. We applied the ecophysiological based model to several global circulation model (GCM) predictions for mid-century. We used global coypu introduction data to evaluate these models and to explore a hypothesized physiological limitation, finding general agreement with known coypu distribution locally and globally and support for an upper thermal tolerance threshold. Global circulation model based model results showed variability in coypu predicted distribution among GCMs, but had general agreement of increasing suitable area in the USA. Our methods highlighted the dynamic nature of the edges of the coypu distribution due to climate non-equilibrium, and uncertainty associated with forecasting future distributions. Areas deemed suitable habitat, especially those on the edge of the current known range, could be used for early detection of the spread of coypu populations for management purposes. Combining approaches can be beneficial to predicting potential distributions of invasive species now and in the future and in exploring hypotheses of factors controlling distributions
Policy Brief: Exploring Response to Intervention’s Effectiveness with Students of Color
This policy analysis explores the effectiveness of Response to Intervention (RTI) at diminishing racial disproportionalities in special education. It includes a brief review of the legislative context of RTI. It also examines one contributing factor to the effectiveness of RTI—educator ideologies. The analysis concludes with implications and future policy directions
VEZF1 elements mediate protection from DNA methylation
There is growing consensus that genome organization and long-range gene regulation involves partitioning of the genome into domains of distinct epigenetic chromatin states. Chromatin insulator or barrier elements are key components of these processes as they can establish boundaries between chromatin states. The ability of elements such as the paradigm β-globin HS4 insulator to block the range of enhancers or the spread of repressive histone modifications is well established. Here we have addressed the hypothesis that a barrier element in vertebrates should be capable of defending a gene from silencing by DNA methylation. Using an established stable reporter gene system, we find that HS4 acts specifically to protect a gene promoter from de novo DNA methylation. Notably, protection from methylation can occur in the absence of histone acetylation or transcription. There is a division of labor at HS4; the sequences that mediate protection from methylation are separable from those that mediate CTCF-dependent enhancer blocking and USF-dependent histone modification recruitment. The zinc finger protein VEZF1 was purified as the factor that specifically interacts with the methylation protection elements. VEZF1 is a candidate CpG island protection factor as the G-rich sequences bound by VEZF1 are frequently found at CpG island promoters. Indeed, we show that VEZF1 elements are sufficient to mediate demethylation and protection of the APRT CpG island promoter from DNA methylation. We propose that many barrier elements in vertebrates will prevent DNA methylation in addition to blocking the propagation of repressive histone modifications, as either process is sufficient to direct the establishment of an epigenetically stable silent chromatin stat
HOW ACQUISITION DECISIONS IMPACTED FLEET READINESS IN THE LCS PLATFORM
The Littoral Combat Ship (LCS) program was initiated to address the U.S. Navy’s need for improved capabilities in littoral environments. This study examines how acquisition decisions impacted the LCS program’s ability to enhance naval readiness. The research combines an in-depth literature review of official documents and reports with the author’s firsthand experience serving on the USS Freedom, USS Fort Worth, and at Littoral Combat Squadron 1. The findings reveal that the LCS program encountered significant operational challenges, cost overruns, and delays in meeting initial capability requirements. Inadequate acquisition and sustainment strategies, including a lack of thorough testing before production and overreliance on contractor support, contributed to these issues. While the Navy has taken steps to address the shortcomings, the LCS’s limitations have strategic implications for littoral power projection and fleet readiness. The study concludes that the LCS program provides valuable lessons for balancing innovation and practicality in naval acquisition. Recommendations include re-evaluating the LCS’s role, enhancing acquisition practices, investing in technology and training, strengthening oversight, and exploring alternative solutions. By applying these lessons, the Navy can improve future acquisition efforts to develop a more agile and cost-effective fleet capable of meeting complex maritime challenges.Distribution Statement A. Approved for public release: Distribution is unlimited.Lieutenant, United States Nav
Stretching the Rules: Monocentric Chromosomes with Multiple Centromere Domains
The centromere is a functional chromosome domain that is essential for faithful chromosome segregation during cell division and that can be reliably identified by the presence of the centromere-specific histone H3 variant CenH3. In monocentric chromosomes, the centromere is characterized by a single CenH3-containing region within a morphologically distinct primary constriction. This region usually spans up to a few Mbp composed mainly of centromere-specific satellite DNA common to all chromosomes of a given species. In holocentric chromosomes, there is no primary constriction; the centromere is composed of many CenH3 loci distributed along the entire length of a chromosome. Using correlative fluorescence light microscopy and high-resolution electron microscopy, we show that pea (Pisum sativum) chromosomes exhibit remarkably long primary constrictions that contain 3-5 explicit CenH3-containing regions, a novelty in centromere organization. In addition, we estimate that the size of the chromosome segment delimited by two outermost domains varies between 69 Mbp and 107 Mbp, several factors larger than any known centromere length. These domains are almost entirely composed of repetitive DNA sequences belonging to 13 distinct families of satellite DNA and one family of centromeric retrotransposons, all of which are unevenly distributed among pea chromosomes. We present the centromeres of Pisum as novel ``meta-polycentric'' functional domains. Our results demonstrate that the organization and DNA composition of functional centromere domains can be far more complex than previously thought, do not require single repetitive elements, and do not require single centromere domains in order to segregate properly. Based on these findings, we propose Pisum as a useful model for investigation of centromere architecture and the still poorly understood role of repetitive DNA in centromere evolution, determination, and function
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