Crocodylus acutus

Number of Pages: 17Integrative BiologyGeological Science

Early warning signals: The charted and uncharted territories

The realization that complex systems such as ecological communities can collapse or shift regimes suddenly and without rapid external forcing poses a serious challenge to our understanding and management of the natural world. The potential to identify early warning signals that would allow researchers and managers to predict such events before they happen has therefore been an invaluable discovery that offers a way forward in spite of such seemingly unpredictable behavior. Research into early warning signals has demonstrated that it is possible to define and detect such early warning signals in advance of a transition in certain contexts. Here we describe the pattern emerging as research continues to explore just how far we can generalize these results. A core of examples emerges that shares three properties: the phenomenon of rapid regime shifts, a pattern of 'critical slowing down' that can be used to detect the approaching shift, and a mechanism of bifurcation driving the sudden change. As research has expanded beyond these core examples, it is becoming clear that not all systems that show regime shifts exhibit critical slowing down, or vice versa. Even when systems exhibit critical slowing down, statistical detection is a challenge. We review the literature that explores these edge cases and highlight the need for (a) new early warning behaviors that can be used in cases where rapid shifts do not exhibit critical slowing down, (b) the development of methods to identify which behavior might be an appropriate signal when encountering a novel system; bearing in mind that a positive indication for some systems is a negative indication in others, and (c) statistical methods that can distinguish between signatures of early warning behaviors and noise

Alligator mississippiensis

Number of Pages: 14Integrative BiologyGeological Science

Graphical Methods in Device-Independent Quantum Cryptography

We introduce a framework for graphical security proofs in device-independent quantum cryptography using the methods of categorical quantum mechanics. We are optimistic that this approach will make some of the highly complex proofs in quantum cryptography more accessible, facilitate the discovery of new proofs, and enable automated proof verification. As an example of our framework, we reprove a previous result from device-independent quantum cryptography: any linear randomness expansion protocol can be converted into an unbounded randomness expansion protocol. We give a graphical proof of this result, and implement part of it in the Globular proof assistant.Comment: Publishable version. Diagrams have been polished, minor revisions to the text, and an appendix added with supplementary proof

Lodging and Other Characteristics of Seventy Corn Hybrids

In 1975, a lodging study was conducted on forty medium season and thirty full season corn hybrids at Knoxville and Crossville, Tennessee. Lodging and yields were determined at Knoxville and Crossville. Senescence over time, ear height, and number of days to silking and tasseling were determined at Knoxville. Senescence, ear height and yield has little or no influence on lodging. Among all the factors evaluated, ear height, senescence, and number of days to silking and tasseling affected yields most in the medium season test. Ear height and number of days to silking and tasseling had the greatest effect on yields in the full season test

PhD

thesisAs observed in these studies, mice in the age range of 6-17 days of age were more susceptible to the injection of staphylococcal supernatants than were older mice. Freezing and thawing the storage of a staphylococcal broth culture at -26° C for seven months did not affect the coagulase titers nor the toxic activity of this culture. It was observed that filtration of staphylococcal broth cultures through Seitz and Mandler filters removed coagulase, but did not affect the toxic activity of these cultures. Millipore filtration did not remove coagulase. Prolonged incubation of Staph. aureaus cultures in the present of increased carbon dioxide favored the production of toxin rather that coagulase. Lethality for suckling was sue to the presence of staphylococcal exotoxin in the cultures and in cell free filtrates rather than coagulase. In addition, cell free filtrates were more lethal than were the cultures which contained organisms. Exposure to boiling temperature of cell free filtrates, prepared from cultures of Staph. aureaus strains 15 and 17, did not destroy the toxic activity of these filtrates as it did with the filtrates of strains 5 and 13. The results obtained with strain 17, a turkey isolate, resembled those of the human strain 15. Cell free filtrates of both strains were quite toxic; however, the toxins of strain 15 appeared to be more heat stable than those of strain 17. No significant immunological difference was shown between the heat labile and the heat stable fractions of staphylococcal exotoxin. In addition, mice injected with a mixture of cell free filtrates plus homologous or heterologous antiserm were not protected from the toxic activity of these filtrates. A positive coagulase test was not obtained with a suspension of Staph. aureus strain 15 heated at 56°C for 75 minutes. However, this treatment did not destroy the ability of this organism to produce coagulase. In the experiment to determine if coagulase in produced in vivo, coagulase could not be detected in the supernatant fluid of a suspension of ground mouse muscle tissue

Theoretical and experimental study of flow-control devices for inlets of indraft wind tunnels

Low-contraction ratio wind tunnel inlets have been shown to generate nonuniform velocity fields in the location where it is necessary to place anti-turbulence screens. The pressure drop experienced by the flow passing through the screens is proportional to the local dynamic pressure and can, therefore, result in a nonuniform test-section velocity distribution. The interaction of screens and two-dimensional inlet flow was examined in this study both theoretically and experimentally. The results indicate that the addition of more screens does not improve the test-section velocity distribution except for a very limited range of inlet geometries. In addition, the turning of the flow by the screens was found to be the most important factor influencing the inlet flow distribution and that the turning action of the screens must be included in any analysis of this type of flow. The use of a set of turning vanes (cascade) upstream of the screens was found to be effective in modifying the inlet flow distribution so as to generate a uniform test-section velocity distribution. A successful application of the inlet cascade to the 80- by 120-Foot Wind Tunnel at NASA Ames Research Center is also presented

Leadership Competencies for the Community College Department Chairperson

Published in 2005, the American Association of Community Colleges developed a list of six leadership competencies deemed by stakeholders as essential to a community college leadership position. The six AACC leadership competencies include organizational strategy, resource management, communication, collaboration, community college advocacy, and professionalism, and they have been well researched with upper-level community college leadership, student services personnel, and boards of trustees. This research examined these competencies as they relate to the community college department chairperson. Often viewed as a path to upper level leadership, the community college chairperson is both a faculty member and administrator, and chairpersons must represent their department or division to both internal constituents (students, other departments, administrators) and external constituents (communities, legislative groups). In addition, faculty members becoming chairpersons learn the position in several recurring ways: graduate programs, in-house leadership programs, on-the-job training, learning from others in a similar position, previous/progressive responsibilities, formal professional development opportunities, challenging job assignments, and mentoring relationships. . The researcher was interested in determining if there were differences in the importance rating of each competency between community college chairpersons and upper level leadership within the community college institution. In addition, the researcher questioned if new chairpersons had similar opinions about the competencies as veteran chairpersons. The researcher also sought to determine if any formal or non-formal experiences allowed the chairperson opportunities to develop the six AACC leadership competencies. Department chairpersons and upper level administrators at all fifteen community colleges in Mississippi (n = 115) were invited to participate in this research by completing a Qualtrics administered survey to assess the importance rating of each competency as evidenced by six different questions per competency. Additionally, respondents were asked if they were trained on each competency, and, if they were trained, to identify the methods utilized in the training. It was determined that no differences existed between the importance rating of each competency by department chairpersons or upper level administrators. There was also no difference in the importance rating of each competency by new chairpersons and veteran chairpersons, and chairpersons most often learned about the competencies by on-the-job training or by learning from a colleague in a similar position

Floating Widgets: Interaction with Acoustically-Levitated Widgets

Acoustic levitation enables new types of human-computer interface, where the content that users interact with is made up from small objects held in mid-air. We show that acoustically-levitated objects can form mid-air widgets that respond to interaction. Users can interact with them using in-air hand gestures. Sound and widget movement are used as feedback about the interaction