Catfish farming

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

Method and apparatus for controlling the approach angle of a plow unit in response to speed variations

A moldboard plow implement includes an elongated tool bar and several moldboard plow units, each plow unit including a plow bottom and a plow bottom support frame connected to the tool bar for pivotal movement about a pivot axis situated in vertical alignment with the point of the respective plow bottom. The plow units are pivotally moved in unison in response to the plowing speed to maintain the specific plow resistance constant for all tractor speeds

Critical Literacy In An EFL Learning Virtual Course

El objetivo de la presente investigación está relacionado con Describir cómo un grupo de estudiantes de nivel intermedio responde a una implementación pedagógica de alfabetización crítica en un curso de EFL en línea en un instituto de idiomas. El estudio tiene un enfoque cualitativo, de nivel descriptivo. La muestra estuvo constituida por seis estudiantes mujeres, todas ellas estudiantes de secundaria de 15 y 16 años; con un dominio del idioma inglés se encuentra en un nivel intermedio B1. Este estudio considera cuatro instrumentos de recolección de datos: observaciones en el aula - videograbaciones y diarios de los docentes, entrevista abierta semiestructurada con el objetivo de captar las representaciones, pensamientos y concepciones que los estudiantes han construido sobre los problemas sociales a través del enfoque de alfabetización crítica implementado para enseñar inglés en un entorno de aprendizaje virtual. Entre los principales hallazgos se encuentra que a partir del desarrollo de la alfabetización multimodal, los estudiantes lograron conocimientos más estructurados en argumentos; además aprendizajes más autónomos como también en un claro incremento de la interacción y el consenso entre estudiantes; finalmente, se incrementó el dominio de las fuentes y la recopilación de la información para el aprendizaje. Se concluye que los participantes sí respondieron efectivamente al desarrollo de habilidades críticas de lectoescritura, a través de un proceso de aprendizaje gradual y satisfactorioThe objective of the present investigation is related to describing how a group of intermediate-level students responds to a pedagogical implementation of critical literacy in an online EFL course at a language institute. The study has a qualitative approach and descriptive level. The sample consisted of six female students, all of them 15 and 16-year-old high school students; with a command of the English language at an intermediate level B1. This study considers four data collection instruments: classroom observations - video recordings and teachers' diaries, semi-structured open interviews with the aim of capturing the representations, thoughts, and conceptions that students have built on social problems through the approach of critical literacy implemented to teach English in a virtual learning environment. Among the main findings is that from the development of multimodal literacy, students achieved more structured knowledge in arguments; also more autonomous learning as well as a clear increase in interaction and consensus among students; finally, the mastery of the sources and the collection of information for learning increased. Overall,  participants responded effectively to the development of critical literacy skills, through a gradual and satisfactory learning process

Application of poultry litter to pine forests

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

Synthesis of Three Isoelemental MXenes and Their Structure–Property Relationships

The MXene family has rapidly expanded since its discovery in 2011 to include nearly 50 unique MXenes, not accounting for solid solutions and diverse surface terminations. However, a question raised since their discovery has been: What is the effect of n? In other words, how does the number of layers affect the MXene properties? To date, no direct study of the impact of n has been conducted due to the lack of isoelemental MXene compositions spanning more than two n values. Herein, we report on a system of three MXenes with identical M-site chemistries, (Mo2/3V1/3)n+1CnTx (n = 1, 2, and 3), allowing for the study of MXene structure–property relationships across n, for the first time. Chemical analysis of the samples shows complete and partial ordering of the M-elements in the n = 2 and 3 samples, respectively. We show that sample stability gradually evolves as n is increased from 1 to 3, while electronic and electrochemical properties exhibit more significant changes in going from n = 1 to 2 than from n = 2 to 3

Semiconductor Lasers: Physics and Applications

Contains an introduction and reports on eight research projects.MIT Lincoln Laboratory Contract BX-6558MIT Lincoln LaboratoryU.S. Navy - Office of Naval Research/MUR

Divergent Serpentoviruses in Free-Ranging Invasive Pythons and Native Colubrids in Southern Florida, United States

Burmese python (Python bivittatus) is an invasive snake that has significantly affected ecosystems in southern Florida, United States. Aside from direct predation and competition, invasive species can also introduce nonnative pathogens that can adversely affect native species. The subfamily Serpentovirinae (order Nidovirales) is composed of positive-sense RNA viruses primarily found in reptiles. Some serpentoviruses, such as shingleback nidovirus, are associated with mortalities in wild populations, while others, including ball python nidovirus and green tree python nidovirus can be a major cause of disease and mortality in captive animals. To determine if serpentoviruses were present in invasive Burmese pythons in southern Florida, oral swabs were collected from both free-ranging and long-term captive snakes. Swabs were screened for the presence of serpentovirus by reverse transcription PCR and sequenced. A total serpentovirus prevalence of 27.8% was detected in 318 python samples. Of the initial swabs from 172 free-ranging pythons, 42 (24.4%) were positive for multiple divergent viral sequences comprising four clades across the sampling range. Both sex and snout-vent length were statistically significant factors in virus prevalence, with larger male snakes having the highest prevalence. Sampling location was statistically significant in circulating virus sequence. Mild clinical signs and lesions consistent with serpentovirus infection were observed in a subset of sampled pythons. Testing of native snakes (n = 219, 18 species) in part of the python range found no evidence of python virus spillover; however, five individual native snakes (2.3%) representing three species were PCR positive for unique, divergent serpentoviruses. Calculated pairwise uncorrected distance analysis indicated the newly discovered virus sequences likely represent three novel genera in the subfamily Serpentovirinae. This study is the first to characterize serpentovirus in wild free-ranging pythons or in any free-ranging North America reptile. Though the risk these viruses pose to the invasive and native species is unknown, the potential for spillover to native herpetofauna warrants further investigation

Gas Source Molecular Beam Epitaxy of Compound Semiconductors

Contains an introduction and reports on seven research projects.Defense Advanced Research Projects Agency Subcontract 284-25041Joint Services Electronics Program Contract DAAL04-95-1-0038National Center for Integrated Photonic Technology Contract 542-381U.S. Army Research Office/ AASERT Contract DAAH04-93-G-0175National Science Foundation Grant DMR 92-02957Joint Services Electronics Program Grant DAAL04-95-1-0038National Science Foundation Grant DMR 90-22933National Science Foundation Grant DMR 92-02957National Center for Integrated Photonic Technology Contract 542-381MIT Lincoln LaboratoryNational Center for Integrated Photonic Technology Subcontract 542-383National Science Foundation DMR 94-0033

First Resolved Scattered-light Images of Four Debris Disks in Scorpius-Centaurus with the Gemini Planet Imager

We present the first spatially resolved scattered-light images of four debris disks around members of the Scorpius-Centaurus (Sco-Cen) OB association with high-contrast imaging and polarimetry using the Gemini Planet Imager (GPI). All four disks are resolved for the first time in polarized light, and one disk is also detected in total intensity. The three disks imaged around HD 111161, HD 143675, and HD 145560 are symmetric in both morphology and brightness distribution. The three systems span a range of inclinations and radial extents. The disk imaged around HD 98363 shows indications of asymmetries in morphology and brightness distribution, with some structural similarities to the HD 106906 planet–disk system. Uniquely, HD 98363 has a wide comoving stellar companion, Wray 15-788, with a recently resolved disk with very different morphological properties. HD 98363 A/B is the first binary debris disk system with two spatially resolved disks. All four targets have been observed with ALMA, and their continuum fluxes range from one nondetection to one of the brightest disks in the region. With the new results, a total of 15 A/F stars in Sco-Cen have resolved scattered-light debris disks, and approximately half of these systems exhibit some form of asymmetry. Combining the GPI disk structure results with information from the literature on millimeter fluxes and imaged planets reveals a diversity of disk properties in this young population. Overall, the four newly resolved disks contribute to the census of disk structures measured around A/F stars at this important stage in the development of planetary systems

The First Near-infrared Transmission Spectrum of HIP 41378 f, A Low-mass Temperate Jovian World in a Multiplanet System

Abstract: We present a near-infrared transmission spectrum of the long-period (P = 542 days), temperate (T eq = 294 K) giant planet HIP 41378 f obtained with the Wide-Field Camera 3 instrument aboard the Hubble Space Telescope (HST). With a measured mass of 12 ± 3 M ⊕ and a radius of 9.2 ± 0.1 R ⊕, HIP 41378 f has an extremely low bulk density (0.09 ± 0.02 g cm−3). We measure the transit depth with a median precision of 84 ppm in 30 spectrophotometric channels with uniformly sized widths of 0.018 μm. Within this level of precision, the spectrum shows no evidence of absorption from gaseous molecular features between 1.1 and 1.7 μm. Comparing the observed transmission spectrum to a suite of 1D radiative-convective-thermochemical-equilibrium forward models, we rule out clear, low-metallicity atmospheres and find that the data prefer high-metallicity atmospheres or models with an additional opacity source, such as high-altitude hazes and/or circumplanetary rings. We explore the ringed scenario for HIP 41378 f further by jointly fitting the K2 and HST light curves to constrain the properties of putative rings. We also assess the possibility of distinguishing between hazy, ringed, and high-metallicity scenarios at longer wavelengths with the James Webb Space Telescope. HIP 41378 f provides a rare opportunity to probe the atmospheric composition of a cool giant planet spanning the gap in temperature, orbital separation, and stellar irradiation between the solar system giants, directly imaged planets, and the highly irradiated hot Jupiters traditionally studied via transit spectroscopy