2,834 research outputs found
A phylogenomic perspective on the radiation of ray-finned fishes based upon targeted sequencing of ultraconserved elements
Ray-finned fishes constitute the dominant radiation of vertebrates with over
30,000 species. Although molecular phylogenetics has begun to disentangle major
evolutionary relationships within this vast section of the Tree of Life, there
is no widely available approach for efficiently collecting phylogenomic data
within fishes, leaving much of the enormous potential of massively parallel
sequencing technologies for resolving major radiations in ray-finned fishes
unrealized. Here, we provide a genomic perspective on longstanding questions
regarding the diversification of major groups of ray-finned fishes through
targeted enrichment of ultraconserved nuclear DNA elements (UCEs) and their
flanking sequence. Our workflow efficiently and economically generates data
sets that are orders of magnitude larger than those produced by traditional
approaches and is well-suited to working with museum specimens. Analysis of the
UCE data set recovers a well-supported phylogeny at both shallow and deep
time-scales that supports a monophyletic relationship between Amia and
Lepisosteus (Holostei) and reveals elopomorphs and then osteoglossomorphs to be
the earliest diverging teleost lineages. Divergence time estimation based upon
14 fossil calibrations reveals that crown teleosts appeared ~270 Ma at the end
of the Permian and that elopomorphs, osteoglossomorphs, ostarioclupeomorphs,
and euteleosts diverged from one another by 205 Ma during the Triassic. Our
approach additionally reveals that sequence capture of UCE regions and their
flanking sequence offers enormous potential for resolving phylogenetic
relationships within ray-finned fishes
Scheduling, Complexity, and Solution Methods for Space Robot On-Orbit Servicing
This research proposes problems, models, and solutions for the scheduling of space robot on-orbit servicing. We present the Multi-Orbit Routing and Scheduling of Refuellable On-Orbit Servicing Space Robots problem which considers on-orbit servicing across multiple orbits with moving tasks and moving refuelling depots. We formulate a mixed integer linear program model to optimize the routing and scheduling of robot servicers to accomplish on-orbit servicing tasks. We develop and demonstrate flexible algorithms for the creation of the model parameters and associated data sets. Our first algorithm creates the network arcs using orbital mechanics. We have also created a novel way to mathematically represent the movement of the tasks and refuelling depots and present algorithms for constructing both sets of data. We create robust case studies based on current operational satellites in Low Earth Orbit, Mid Earth Orbit, and Geosynchronous Earth Orbit. With these case studies we perform extensive computational experiments to present example insights about robot servicers, task completion, and their use of refuelling depots.
Building upon this work, we next focus on proving the computational complexity and generating fast, accurate algorithms and present and demonstrate two solution methods. The solution methods use node labels akin to those in Dijkstra\u27s algorithm but include much more information about the servicers, tasks, and fuel levels. We use the labels to find the shortest paths to tasks which are in motion on the network. The first heuristic assigns servicers to tasks greedily and the second heuristic assigns tasks using a clustering algorithm. We use a case study to compare our heuristic time and solution performance with CPLEX with promising results.
In our final work, we address the Multi-Orbit Routing and Scheduling of Refuellable On-Orbit Servicing Space Robots with Known Task Times. Previously, we considered the tasks to have instantaneous completion which is realistic for surveillance type tasks but not for the more intricate tasks, such as corrective maintenance or equipment upgrade. Thus we remove the assumption of instantaneous task completion and consider a known task processing time. We present a new mixed integer linear program model to optimize the routing and scheduling of robot servicers to accomplish the on-orbit servicing tasks. As both tasks and servicers move, considering task duration is complex because (i) the task and servicer must coincide at the correct location and time, (ii) the task and servicer must move through the network together for at least the duration of the processing time, and (iii) the completion of the task is at a different location and time than the start. The model accounts for the movement of the servicers, tasks, and refuelling depots and also for the task duration. We also present two related constructive heuristics for solving the problem. We also incorporate the task times into a case study which is based on satellites and orbits which are in use today. We use the case study to conduct computational experiments comparing the heuristic solving times and solution accuracy with CPLEX
The boll weevil in Missouri : history, biology and management
"Original author: Clyde E. Sorenson""The cotton boll weevil, Anthonomus grandis grandis, was the most important pest of cotton in much of America's Cotton Belt. Fortunately, it was eradicated in the United States by a U.S. Department of Agriculture (USDA) program in cooperation with state agencies and cotton farmers. In Missouri, the eradication started in 2001 and lasted seven years. The weevil's importance was due not only to the considerable damage it does but also to its disruption of management programs that target other pests. High numbers of boll weevils caused repeated insecticide applications during the growing season because the boll weevil went through several overlapping generations during every crop season, reproduced quickly, moved often and could be controlled with insecticides only during its adult stage. Applying insecticides reduced populations of organisms that regulate the populations of other cotton pests, such as aphids, plant bugs and the bollworm complex. The presence of significant boll weevil populations dictated, to some extent, the management of other pests."--First page.Written by; Clyde E. Sorenson (formerly of the MU Delta Center), Gene Stevens (Extension Professor, Agronomy)New 4/95; Revised 9/1
The Family Council: A Model for Corporate Leisure Time Planning
The family has undergone change. The most important concern is how to improve family conditions. A family council will help families to better focus and help each member better understand the other\u27s position. The council will help provide · a structure and a format for decision-making which will provide a forum for democratic input from all members
Real-Time Temperature Sensing Using a Ratiometric Dual Fluorescent Protein Biosensor
Accurate temperature control within biological and chemical reaction samples and instrument calibration are essential to the diagnostic, pharmaceutical and chemical industries. This is particularly challenging for microlitre-scale reactions typically used in real-time PCR applications and differential scanning fluorometry. Here, we describe the development of a simple, inexpensive ratiometric dual fluorescent protein temperature biosensor (DFPTB). A combination of cycle three green fluorescent protein and a monomeric red fluorescent protein enabled the quantification of relative temperature changes and the identification of temperature discrepancies across a wide temperature range of 4–70 °C. The maximal sensitivity of 6.7% °C−1 and precision of 0.1 °C were achieved in a biologically relevant temperature range of 25–42 °C in standard phosphate-buffered saline conditions at a pH of 7.2. Good temperature sensitivity was achieved in a variety of biological buffers and pH ranging from 4.8 to 9.1. The DFPTB can be used in either purified or mixed bacteria-encapsulated formats, paving the way for in vitro and in vivo applications for topologically precise temperature measurements
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Universal Design for Learning in K-12 Educational Settings: A Review of Group Comparison and Single-subject Intervention Studies
This literature review on Universal Design for Learning (UDL) included articles from January 1984 through June 2014. We (a) investigated the UDL educational framework without the inclusion of other major K-12 educational frameworks in learning environments, (b) reported researchers’ scope and depth of use of the UDL principles, and (c) focused our investigation on two research methods: group comparison and single-subject. We used the quality indicators for evidence-based practices (EBPs) in special education to review, not rate, the final pool of five peer-reviewed articles. Results included analyses of the incorporation of UDL principles in all identified studies, highlighting the need for caution in promoting conceptual frameworks until sufficient empirical evidence is available to validate pedagogical utility in educational environments. We conclude that the UDL framework has merit but researchers must conduct studies that use group comparison and single-subject studies to independently test the UDL principles, guidelines, and checkpoints to increase the likelihood of causation in treatment outcomes
Study to determine experimentally the feasibility of new methods for improving thermal conductance of mechanical joints in a vacuum Summary research report, 8 Apr. - 30 Sep. 1966
Surface-plateauing techniques, and flexible surface membranes for improved thermal conductance of mechanical joints in vacuu
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