Corn grain yield response to nitrogen rate and plant population in full and double-crop systems

Interest in incorporating non-traditional crops like corn (Zea mays) into double-crop rotations in Oklahoma has increased recently. Work in other crops suggests differences in management between full season and double-crop, though there is limited information available on corn as a constituent of the double-crop system. As two of the most expensive inputs for corn production, optimizing nitrogen (N) application and plant populations is critical for high-risk double-crop systems. One trial was conducted over two years at three locations to determine grain yield response to these factors and assess best management practices for a double-crop wheat-corn rotation.The study was designed to evaluate the differences between grain yield and physiological yield characteristics as they were affected by nitrogen rate and plant population treatments. Tests were conducted in 2020 and 2021 in Oklahoma. The yield characteristics evaluated were grain N (%), average kernel row⁻¹, average row cob⁻¹, kernel number, kernel weight, and cob weight. The results indicate lower yield performance at plant populations exceeding 57,000 plants ha⁻¹, though not by significant margins. This phenomenon may be explained by competition-induced stress at high plant populations. Varying responses to N rate was recorded at each location, though the best performance was recorded between 82.5 and 110 kg ha⁻¹. Though statistical analysis between full season and double-crop trials was not performed, preliminary results indicate lower N requirement for the double-crop. This may be explained by reduced biomass and dry matter accumulation fostered by the short double-crop season. Average kernel row⁻¹ was significantly impacted by plant population consistently, while N rate had limited effect.It was concluded that grain yield was impacted by the combined effects of plant population and N rate, suggesting optimal management of both aspects is critical. Excessive plant populations create high levels of resource competition resulting in yield reductions. A result of rapid maturation of corn in this system is reduced biomass where less time is spent in vegetative growth stages. These factors alter the capability of corn to utilize N resources

Teachers’ Perspectives of the Impact of Social Emotional Learning on Student Behavior

This Record of Study evaluated teachers’ perceptions of the impact Social Emotional Learning (SEL) can have on student behaviors and how teachers’ belief systems relate to their implementation of SEL within their classrooms. An explanatory sequential mixed methods design was used to develop a comprehensive picture of teachers’ perceptions. SEL is a process through which individuals can acquire and manage personal and interpersonal skills to help them be successful in life. Utilizing CASEL’s Framework for SEL, teacher’s perceptions about the impact Social Emotional Learning has had on specific student behaviors as they relate to the five components within the Framework were analyzed. This study also explored the way in which a teacher’s belief system relates to their implementation of SEL practices. Their level of implementation and implementation practices were analyzed. This study began with initial quantitative data in the form of a questionnaire provided to all face-to-face teachers on campus. Responses were analyzed using a Likert scale based on participants’ responses. From the twenty-three participants, five were selected for qualitative research in the form of interviews, observations, and artifacts to further explain the quantitative data. This data was transcribed and coded for trends and themes as it relates to teachers’ perceptions of student behavior and their implementation of SEL. Analyzing the data found that students’ behaviors within each of the five components were observed more positively by teachers overall and there was an overall growth in student behavior after implementing SEL practices within the classrooms. Additionally, it was found that a teacher’s level of belief did not relate to their frequency of implementation, but it related to the method of implementation. This study will be used to provide improvements to SEL implementation in the future

Enterprise Risk Management Strategies for Organizational Sustainability

The purpose of this single case study was to explore enterprise risk management strategies that nonprofit business leaders used to maintain and improve organizational sustainability. The study population included 3 executive leaders from a rehabilitation and social services nonprofit agency located in the northeastern United States. The Committee of Sponsoring Organizations integrated enterprise risk management framework was the conceptual lens used in this study. Data were collected through semistructured interviews with the 3 executive leaders of the client organization and review of internal, external, and publicly available documents. Data and information from documents and interviews were manually coded. Findings were validated through data triangulation and member checking to help ensure accuracy, consistency, and credibility. Several overarching themes emerged from data analysis related to managing risk for sustainability: a commitment to culture and the mission, vision and values; operational efficiencies to build a financially strong organization; engagement of executive staff and board members; and addressing staffing needs for ongoing operations to meet client needs. Findings from this study might contribute to positive social change by providing nonprofit leaders with enterprise risk management strategies and processes to maintain and improve organizational performance, thereby helping to ensure leaders’ ability to serve and improve their communities

Management of double-crop corn system

The Oklahoma Cooperative Extension Service periodically issues revisions to its publications. The most current edition is made available. For access to an earlier edition, if available for this title, please contact the Oklahoma State University Library Archives by email at [email protected] or by phone at 405-744-6311

Managing double-crop soybean inputs

The Oklahoma Cooperative Extension Service periodically issues revisions to its publications. The most current edition is made available. For access to an earlier edition, if available for this title, please contact the Oklahoma State University Library Archives by email at [email protected] or by phone at 405-744-6311

Maturation-Induced Cloaking of Neutralization Epitopes on HIV-1 Particles

To become infectious, HIV-1 particles undergo a maturation process involving proteolytic cleavage of the Gag and Gag-Pol polyproteins. Immature particles contain a highly stable spherical Gag lattice and are impaired for fusion with target cells. The fusion impairment is relieved by truncation of the gp41 cytoplasmic tail (CT), indicating that an interaction between the immature viral core and gp41 within the particle represses HIV-1 fusion by an unknown mechanism. We hypothesized that the conformation of Env on the viral surface is regulated allosterically by interactions with the HIV-1 core during particle maturation. To test this, we quantified the binding of a panel of monoclonal antibodies to mature and immature HIV-1 particles by immunofluorescence imaging. Surprisingly, immature particles exhibited markedly enhanced binding of several gp41-specific antibodies, including two that recognize the membrane proximal external region (MPER) and neutralize diverse HIV-1 strains. Several of the differences in epitope exposure on mature and immature particles were abolished by truncation of the gp41 CT, thus linking the immature HIV-1 fusion defect with altered Env conformation. Our results suggest that perturbation of fusion-dependent Env conformational changes contributes to the impaired fusion of immature particles. Masking of neutralization-sensitive epitopes during particle maturation may contribute to HIV-1 immune evasion and has practical implications for vaccine strategies targeting the gp41 MPER

Topology of the C-Terminal Tail of HIV-1 gp41: Differential Exposure of the Kennedy Epitope on Cell and Viral Membranes

The C-terminal tail (CTT) of the HIV-1 gp41 envelope (Env) protein is increasingly recognized as an important determinant of Env structure and functional properties, including fusogenicity and antigenicity. While the CTT has been commonly referred to as the “intracytoplasmic domain” based on the assumption of an exclusive localization inside the membrane lipid bilayer, early antigenicity studies and recent biochemical analyses have produced a credible case for surface exposure of specific CTT sequences, including the classical “Kennedy epitope” (KE) of gp41, leading to an alternative model of gp41 topology with multiple membrane-spanning domains. The current study was designed to test these conflicting models of CTT topology by characterizing the exposure of native CTT sequences and substituted VSV-G epitope tags in cell- and virion-associated Env to reference monoclonal antibodies (MAbs). Surface staining and FACS analysis of intact, Env-expressing cells demonstrated that the KE is accessible to binding by MAbs directed to both an inserted VSV-G epitope tag and the native KE sequence. Importantly, the VSV-G tag was only reactive when inserted into the KE; no reactivity was observed in cells expressing Env with the VSV-G tag inserted into the LLP2 domain. In contrast to cell-surface expressed Env, no binding of KE-directed MAbs was observed to Env on the surface of intact virions using either immune precipitation or surface plasmon resonance spectroscopy. These data indicate apparently distinct CTT topologies for virion- and cell-associated Env species and add to the case for a reconsideration of CTT topology that is more complex than currently envisioned