390 research outputs found
Construction of a Forced-Choice University Instructor Rating Scale
Statement of the Problem: The problem, the construction of a rating scale for student evaluation of college teachers, had both pure and applied psychological research aspects. The pure facet of the problem was to develop, apply, and test the effectiveness of certain forced-choice principles of rating scale construction. The applied aspect was to construct in instrument useful to college teachers in the practice of their profession. Quotation marks are used for these terms to indicated the artificial nature of the dualism applied
Good-Bye Dolly Gray : March & Two Step
https://digitalcommons.library.umaine.edu/mmb-ps/1798/thumbnail.jp
From Soil Ecology to Human Nutrtition: Crop Symbiosis with Arbuscular Mycorrhizal Fungi in Agroecosystems
The Green Revolution helped us reduce global poverty, hunger, and malnutrition over the past 30 years. My research is part of an emerging Brown Revolution that is unlocking the power of living soil to sustainability provide human needs. We are losing soil more quickly than it is being replenished � worldwide, an area of farmland the size of half an Oklahoma erodes away every year; however, arbuscular mycorrhizal (AM) fungi are microorganisms that can stabilize and enhance soil, while benefitting most of our crops with increased water and nutrients. A teacup of healthy soil contains enough AM fungi to stretch across 30 football fields from end to end, but some agricultural practices reduce the abundance of AM fungi on farms. These practices degrade soil stability and fertility over time, resulting in a waste of water, a waste of fertilizers, and environmental damage. My research seeks to harness the benefits of AM fungi for sustainable food production and nutrition. We focused on sorghum and cowpea, because they are important in many developing countries, but their efficiency and drought-tolerance also make them ideal for places like Oklahoma. In the greenhouse and field, we assessed differences in plant response to AM fungi to discover which crop genotypes are the most effective partners. Then we examined how that partnership affected agricultural efficiency and seed (grain) nutritional contents, such as protein, zinc, and iron. We also assessed the impact of alternative fertility amendments (biochar, worm compost, reduced commercial fertilizers) and farm management practices (intercropping) on AM abundance, crop yield, and nutrition. More AM responsive genotypes and alternative amendments were shown to increase yield and/or key nutritional contents. Nearly 1 out of every 3 people on this planet are malnourished, and they often need more dietary protein, zinc, and iron; therefore, our results indicate that AM fungi improve soil health and human health as well. Crop genetics, alternative soil amendments, and farm management can enhance the benefits of AM fungi, and we can utilize them to help us regenerate our soils and nourish our growing population.Natural Resources and Ecology Managemen
Recommended from our members
Too proud to lead: how hubris can destroy effective leadership and what to do about it
Incipient speciation in Drosophila melanogaster involves chemical signals.
The sensory and genetic bases of incipient speciation between strains of Drosophila melanogaster from Zimbabwe and those from elsewhere are unknown. We studied mating behaviour between eight strains – six from Zimbabwe, together with two cosmopolitan strains. The Zimbabwe strains showed significant sexual isolation when paired with cosmopolitan males, due to Zimbabwe females discriminating against these males. Our results show that flies' cuticular hydrocarbons (CHs) were involved in this sexual isolation, but that visual and acoustic signals were not. The mating frequency of Zimbabwe females was highly significantly negatively correlated with the male's relative amount of 7-tricosene (%7-T), while the mating of cosmopolitan females was positively correlated with %7-T. Variation in transcription levels of two hydrocarbon-determining genes, desat1 and desat2, did not correlate with the observed mating patterns. Our study represents a step forward in our understanding of the sensory processes involved in this classic case of incipient speciation
Factors affecting follower responses to movement calls in cooperatively breeding dwarf mongooses
In social species, individuals maximize the benefits of group living by remaining cohesive and coordinating their actions. Communication is key to collective action, including ensuring that group members move together; individuals often produce signals when attempting to lead a group to a new area. However, the function of these signals, and how responses to them are affected by intrinsic characteristics of the caller and extrinsic factors, has rarely been experimentally tested. We conducted a series of field-based playback experiments with habituated wild dwarf mongooses, Helogale parvula, a cooperatively breeding and territorial species, to investigate follower responses to movement calls. In our first experiment, we found that focal individuals were more likely to respond to playback of ‘movement calls’ than control ‘close calls’, indicating movement calls function as recruitment signals. In a second experiment, we found that focal individuals responded similarly to the movement calls of dominant and subordinate groupmates, suggesting that dominance status (an intrinsic factor) does not influence receiver responses. In a final experiment, we found that individuals responded to the simulated presence of a rival group, but that this outgroup conflict (an extrinsic factor) did not affect responses to movement calls compared to a control situation. This may be because attention is instead focused on the potential presence of an imminent threat. By using playbacks to isolate the acoustic signal from physical movement cues, our results provide experimental evidence of how movement calls help leaders to attract followers and thus adds to our understanding of recruitment signals more generally
The Impact of Laser Control on The Porosity And Microstructure of Selective Laser Melted Nickel Superalloy 718
Additively manufacturing high performance metals by laser processing represents an exciting opportunity to exploit localized properties by varying input parameters throughout the process. This work explores the solidification and microstructural properties of selectively laser melted (SLM) Inconel 718 (IN718) using unique processing parameters. By employing traditional pulsed laser physics techniques, samples were manufactured with a continuous wave laser to study a potential ubiquitous approach. While the overall power density was controlled, the power, speed, and hatch spacing were varied. The porosity and grain sizes of the samples were characterized by optical and scanning electron microscopes. The influence of processing parameters showed physical differences in the final samples. Sample degradation was observed in higher power processes with porosity up 10%, likely due to increased temperatures and more intense thermal gradients
- …