1,054 research outputs found

    YF-17/ADEN system study

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    The YF-17 aircraft was evaluated as a candidate nonaxisymmetric nozzle flight demonstrator. Configuration design modifications, control system design, flight performance assessment, and program plan and cost we are summarized. Two aircraft configurations were studied. The first was modified as required to install only the augmented deflector exhaust nozzle (ADEN). The second one added a canard installation to take advantage of the full (up to 20 deg) nozzle vectoring capability. Results indicate that: (1) the program is feasible and can be accomplished at reasonable cost and low risk; (2) installation of ADEN increases the aircraft weight by 600 kg (1325 lb); (3) the control system can be modified to accomplish direct lift, pointing capability, variable static margin and deceleration modes of operation; (4) unvectored thrust-minus-drag is similar to the baseline YF-17; and (5) vectoring does not improve maneuvering performance. However, some potential benefits in direct lift, aircraft pointing, handling at low dynamic pressure and takeoff/landing ground roll are available. A 27 month program with 12 months of flight test is envisioned, with the cost estimated to be 15.9millionforthecanardequippedaircraftand15.9 million for the canard equipped aircraft and 13.2 million for the version without canard. The feasiblity of adding a thrust reverser to the YF-17/ADEN was investigated

    A Computer Simulation Model of Waterhyacinth and Weevil Interactions

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    A personal computer simulation model termed INSECT has been developed to evaluate biological control of waterhyacinth (Eichhornia crassipes (Mart.) Solms.) by two species of weevil (Neochetina eichhorniae Warner, and N. bruchi Hustache). The model results were compared with the data from three different locations. For each data set, the simulated plant biomass, adult and larva populations were plotted aqainst the 95% confidence intervals of the actual field observations. In many cases, the simulation results were within the 95% confidence intervals, and especially during the growing season, they indicated trends similar to those seen in the field data. However, there were discrepancies in both the magnitude and the trend for early and the late periods of the year. These initial results suggest that development of a model to simulate the impact of a biocontrol agent on waterhyacinth populations is a feasible approach to better understand the interactions within this control system

    Implementing Classroom PBIS in Georgia Turnaround (or Other) Schools

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    While supporting three schools identified in Cohort I of the Georgia Turnaround Schoolsā€™ Initiative, the PBIS external coach worked with PBIS school teams to develop a framework for redelivery of the Georgia Department of Educationā€™s Classroom PBIS curriculum. To document fidelity of implementation, baseline and progress monitoring data were obtained through classroom walk-through observations. Tools were developed to facilitate that data collection and analysis process. Following monthly and/or bimonthly walk-though observations, a tiered system of coaching supports was established and implemented using each schoolā€™s administration, PBIS Coach, academic coach, and/or external coach depending on the individualized needs of each teacher. This process will be explained to participants. Successes and challenges will be shared along with tools and schoolwide data-driven results. Classroom PBIS is an evidence-based intervention of Tier I PBIS which promotes student resiliency, improves school and classroom climates, and reduces exclusionary discipline practices when implemented with fidelity

    Mining the TRAF6/p62 interactome for a selective ubiquitination motif

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    A new approach is described here to predict ubiquitinated substrates of the E3 ubiquitin ligase, TRAF6, which takes into account its interaction with the scaffold protein SQSTM1/p62. A novel TRAF6 ubiquitination motif defined as [ā€“(hydrophobic)ā€“kā€“(hydrophobic)ā€“xā€“xā€“(hydrophobic)ā€“ (polar)ā€“(hydrophobic)ā€“(polar)ā€“(hydrophobic)] was identified and used to screen the TRAF6/p62 interactome composed of 155 proteins, that were either TRAF6 or p62 interactors, or a negative dataset, composed of 54 proteins with no known association to either TRAF6 or p62. NRIF (K19), TrkA (K485), TrkB (K811), TrkC (K602 and K815), NTRK2 (K828), NTRK3 (K829) and MBP (K169) were found to possess a perfect match for the amino acid consensus motif for TRAF6/p62 ubiquitination. Subsequent analyses revealed that this motif was biased to the C-terminal regions of the protein (nearly 50% the sites), and had preference for loops (~50%) and helices (~37%) over beta-strands (15% or less). In addition, the motif was observed to be in regions that were highly solvent accessible (nearly 90%). Our findings suggest that specific Lysines may be selected for ubiquitination based upon an embedded code defined by a specific amino acid motif with structural determinants. Collectively, our results reveal an unappreciated role for the scaffold protein in targeting ubiquitination. The findings described herein could be used to aid in identification of other E3/scaffold ubiquitination sites

    Wood Property Variation of Mississippi Delta Hardwoods

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    Variation in specific gravity, fiber length, fiber dimensions, and volumetric composition were investigated for selected heights and growth rings of five Mississippi Delta hardwood species: black willow, willow oak, sycamore, pecan, and sugarberry. Variation of specific gravity with age of the cambium was not only different from species to species, but was also different at different sampling heights. The fiber length-age relationship in study trees conformed to the general pattern of large increases in fiber length with age in rings near the pith, followed by a more gradual increase until a maximum was reached. Variations in fiber diameter were not great, but in all species, cell diameter decreased as height in the stem increased. Thin-walled fibers were found near the pith and thick-walled fibers developed in the outermost growth increments.Volumetric composition data revealed large variations between sampling points. The general pattern with age was a linear or curvilinear increase in vessel volume with a corresponding decrease in fiber volume, while ray volume remained constant or increased slightly with age.Correlation analysis was used to evaluate the interrelationships of measured properties in three different species (willow, sugarberry, and pecan). Wide growth rings in these species contained proportionately fewer vessels and more fibers than narrow growth rings as well as shorter fibers. High specific gravity was associated with increased fiber volume. However, the analysis showed no significant differences in specific gravity resulting from variations in growth rate

    A Method to Identify p62's UBA Domain Interacting Proteins

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    The UBA domain is a conserved sequence motif among polyubiquitin binding proteins. For the first time, we demonstrate a systematic, high throughput approach to identification of UBA domain-interacting proteins from a proteome-wide perspective. Using the rabbit reticulocyte lysate in vitro expression cloning system, we have successfully identified eleven proteins that interact with p62ā€™s UBA domain, and the majority of the eleven proteins are associated with neurodegenerative disorders, such as Alzheimerā€™s disease. Therefore, p62 may play a novel regulatory role through its UBA domain. Our approach provides an easy route to the characterization of UBA domain interacting proteins and its application will unfold the important roles that the UBA domain plays

    Binary continuous random networks

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    Many properties of disordered materials can be understood by looking at idealized structural models, in which the strain is as small as is possible in the absence of long-range order. For covalent amorphous semiconductors and glasses, such an idealized structural model, the continuous-random network, was introduced 70 years ago by Zachariasen. In this model, each atom is placed in a crystal-like local environment, with perfect coordination and chemical ordering, yet longer-range order is nonexistent. Defects, such as missing or added bonds, or chemical mismatches, however, are not accounted for. In this paper we explore under which conditions the idealized CRN model without defects captures the properties of the material, and under which conditions defects are an inherent part of the idealized model. We find that the density of defects in tetrahedral networks does not vary smoothly with variations in the interaction strengths, but jumps from close-to-zero to a finite density. Consequently, in certain materials, defects do not play a role except for being thermodynamical excitations, whereas in others they are a fundamental ingredient of the ideal structure.Comment: Article in honor of Mike Thorpe's 60th birthday (to appear in J. Phys: Cond Matt.

    March Madness: NCAA Tournament Participation and College Alcohol Use

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    While athletic success may improve the visibility of a university to prospective students and thereby benefit the school, it may also increase risky behavior in the current student body. Using the Harvard School of Public Health College Alcohol Study, we find that a school\u27s participation in the NCAA Basketball Tournament is associated with a 47% increase in binge drinking by male students at that school. Additionally, we find evidence that drunk driving increases by 5% among all students during the tournament. (JEL I12, I23, Z28

    Signaling, Polyubiquitination, Trafficking, and Inclusions: Sequestosome 1/p62's Role in Neurodegenerative Disease

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    Aggregated misfolded proteins are hallmarks of most neurodegenerative diseases. In a chronic disease state, including pathologic situations of oxidative stress, these proteins are sequestered into inclusions. Accumulation of aggregated proteins can be prevented by chaperones, or by targeting their degradation to the UPS. If the accumulation of these proteins exceeds their degradation, they may impair the function of the proteasome. Alternatively, the function of the proteasome may be preserved by directing aggregated proteins to the autophagy-lysosome pathway for degradation. Sequestosome 1/p62 has recently been shown to interact with polyubiquitinated proteins through its UBA domain and may direct proteins to either the UPS or autophagosome. P62 is present in neuronal inclusions of individuals with Alzheimer's disease and other neurodegenerative diseases. Herein, we review p62's role in signaling, aggregation, and inclusion formation, and specifically as a possible contributor to Alzheimer's disease. The use of p62 as a potential target for the development of therapeutics and as a disease biomarker is also discussed
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