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2017 Texas High Plains and Panhandle Replicated Agronomic Cotton Evaluation (RACE) Trials
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Using Light-Level Geolocator Technology to Examine Movement Ecology for an Endangered Songbird, the Golden-Cheeked Warbler
No full textSixty percent of neotropical migratory songbirds have experienced population declines over the last century and there is growing evidence that events during non-breeding periods contribute to their declines. Unfortunately, we lack data to describe habitat associations and movements during non-breeding periods for most species. Such information is necessary to develop and implement effective conservation strategies for migratory songbirds, but can be difficult to obtain given the size of most tracking devices. One exception is the miniaturized light-level geolocator, which records light intensity data that can be used to estimate locations once the device is retrieved. The golden-cheeked warbler (Setophaga chrysoparia; hereafter warbler) is a very small (1 winter location. Warblers exhibited weak migratory connectivity, however, given their relatively narrow migration pathway and small winter range, continued and increased conservation in non-breeding areas could help ensure population persistence and protect co-occurring species
Why Teach Science: Purposes for Teaching Communicated by Three Science Education Stakeholder Groups
Get PDFReasons why someone chooses to be a teacher sustains oneself during struggles and throughout one���s career. While purposes for teaching evolve over time, educators often base their purposes upon their own intrinsic motivators, including the subject matter they teach or their prior experiences with teaching and learning. This dissertation is guided by one major question: Why should educators teach science? I qualitatively investigated purposes for teaching science across three major stakeholders to elementary science education. First, I investigated purposes communicated across the country���s elementary science standards. Results from this study point to three major categories of purposes for teaching science well established and supported in the elementary science education literature: use of skills, understanding science, and economic readiness. Second, I analyzed purposes among science teacher educators across the country. Results from interviewing 12 faculty point to three major purposes for teaching science held by elementary teacher educators: they wish to promote student growth and development from learning science; they want to foster large-scale progress for humanity, technology, and science; and they prefer science content over and above other subject areas. Third, I examined purposes preservice teachers communicated in their teaching philosophy statements. I found their teaching philosophy statements primarily communicate three ideas: how they think they are ready to teach, what they wanted their students to achieve, and how they intend to get them to do so. Overall, I qualitatively coded for ideas of purpose across these groups. While I did not find equilateral coherence, the three major groups share an interest in teaching science for understanding and developing skills. This should be true of all subject matter teaching. Interestingly, each group presented at least one unique category of purpose for teaching: within standards documents, purposes centered economic readiness; teacher educators focused on their preference for the subject area; preservice teachers emphasized their own ability and likeness to be a teacher as well as focusing on what they would do as teachers
Synthesis of Supramolecules as Adjustable Viscosity Modifiers and Study of Their Interfacial Behavior and Applications
No full textRecently, the interest in stimuli-responsive and adaptable materials has continuously grown in various fields and applications. For such responsive systems, different triggers, including pH, light, pressure, temperature, and electric field, have been utilized to control dynamics and assembly. Among these, pH is one of the most convenient, energy-efficient, and economic modalities. Besides, viscosity modifying agents are one of the most critical components of hydraulic fracturing fluids. To improve the productivity index of hydraulic fracturing processes, better viscosifiers with a higher proppant carrying capacity and a lower potential of formation damage are needed. However, plenty of traditional materials have poor thermal and salt stability, limiting their applications.
Herein, we report several findings of supramolecular systems including a new design of a pH-responsive viscoelastic supramolecular complex (VSC) by complexing a new long-chain amino-amide and maleic acid. The system demonstrated a sol-gel-sol transition from pH 2 to 10, with the largest static viscosity occurring at pH 6 (~1000 Pa��s) and the smallest viscosity at pH 4 (~3.3 Pa��s), indicating ~300-fold control over the viscosity; a novel pH- and temperature-responsive binary supramolecular assembly involving a long-chain hydroxyamino amide (HAA) and an inorganic hydrotrope, boric acid, with highly-tunable viscous and viscoelastic properties. The system under investigation demonstrates a high degree of control over its viscosity, with the capacity to achieve over four orders of magnitude of control through the concomitant manipulation of pH and temperature; a novel viscoelastic system relying on the complexation of zwitterionic octadecylamidopropyl betaine (OAPB) and diethylenetriamine (DTA) in water. At a concentration of 2 wt%, the zwitterionic complex fluid had a static viscosity of 9 to 200 poise, which could be reversibly adjusted by changing the suspension pH; and investigate the influence of alkyl chain length on the self-assembly of long-chain amidopropyl betaines (CnDAB) and the effect of complexation with various degree of amines on viscoelastic supramolecular structures.
Aside from applications in hydraulic fracturing and enhanced oil recovery, we anticipate that the intriguing rheological properties of this viscoelastic system can be beneficial for other chemical engineering applications including personal care products, cosmetics, lubricants, and biomedical gels
