1,178 research outputs found

    Quadruped Gait Learning Using Cyclic Genetic Algorithms

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    Generating walking gaits for legged robots is a challenging task. Gait generation with proper leg coordination involves a series of actions that are continually repeated to create sustained movement. In this paper we present the use of a Cyclic Genetic Algorithm (CGA) to learn gaits for a quadruped servo robot with three degrees of movement per leg. An actual robot was used to generate a simulation model of the movement and states of the robot. The CGA used the robot\u27s unique features and capabilities to develop gaits specific for that particular robot. Tests done in simulation show the success of the CGA in evolving a reasonable control program and preliminary tests on the robot show that the resultant control program produces a suitable gait

    Master equation approach to DNA-breathing in heteropolymer DNA

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    After crossing an initial barrier to break the first base-pair (bp) in double-stranded DNA, the disruption of further bps is characterized by free energies between less than one to a few kT. This causes the opening of intermittent single-stranded bubbles. Their unzipping and zipping dynamics can be monitored by single molecule fluorescence or NMR methods. We here establish a dynamic description of this DNA-breathing in a heteropolymer DNA in terms of a master equation that governs the time evolution of the joint probability distribution for the bubble size and position along the sequence. The transfer coefficients are based on the Poland-Scheraga free energy model. We derive the autocorrelation function for the bubble dynamics and the associated relaxation time spectrum. In particular, we show how one can obtain the probability densities of individual bubble lifetimes and of the waiting times between successive bubble events from the master equation. A comparison to results of a stochastic Gillespie simulation shows excellent agreement.Comment: 12 pages, 8 figure

    The Role of Patient Activation in Preferences for Shared Decision Making: Results From a National Survey of US Adults

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    Financial support for this study was provided by a contract with UnitedHealthcare, Optum Institute. The funding agreement ensured our independence in designing the study, interpreting the data, and writing and publishing the report. Samuel G. Smith is supported by a Cancer Research UK Postdoctoral Fellowship (C42785=A17965). Carol J. Simon and Steven R. Rush are employed by the sponsor

    Draft genome sequence of Frankia sp. strain DC12, an atypical, noninfective, ineffective isolate from Datisca cannabina

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    Frankia sp. strain DC12, isolated from root nodules of Datisca cannabina, is a member of the fourth lineage of Frankia, which is unable to reinfect actinorhizal plants. Here, we report its 6.88-Mbp high-quality draft genome sequence, with a G+C content of 71.92% and 5,858 candidate protein-coding genes

    The use of storytelling in therapy with children

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    This study was a qualitative study that asked clinicians from any discipline to describe how they use storytelling in their clinical practices. Two primary research questions were addressed; the first being to ascertain whether or not clinicians are using storytelling and the second question was to learn how they are using this technique in practice. 13 subjects responded to an on-line electronic survey that was distributed using a snowball method of sampling. Several themes emerged through the narratives of the participants regarding how they use storytelling in their practices. These themes were: Conceptualization of storytelling; Choices of implementation; Content of stories; Importance of narrative; Population choices. The findings of the research revealed that all 13 clinicians believed there are benefits to using storytelling in therapy with children, however there was significant variation in the conceptualization and application of therapeutic storytelling reported among the study participants, as well population choices deemed appropriate to receive a therapeutic storytelling technique. Participants reported benefits and obstacles to using storytelling in therapy with children. The research indicates social work graduate curricula should include information on the effective uses of storytelling in therapy, and evidence-based treatment research into storytelling would benefit the field of social work, as clinicians would be better informed as to the techniques they choose to employ

    The performance of human papillomavirus high-risk DNA testing in the screening and diagnostic settings.

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    OBJECTIVE: We sought to evaluate the performance of the human papillomavirus high-risk DNA test in patients 30 years and older. MATERIALS AND METHODS: Screening (n=835) and diagnosis (n=518) groups were defined based on prior Papanicolaou smear results as part of a clinical trial for cervical cancer detection. We compared the Hybrid Capture II (HCII) test result with the worst histologic report. We used cervical intraepithelial neoplasia (CIN) 2/3 or worse as the reference of disease. We calculated sensitivities, specificities, positive and negative likelihood ratios (LR+ and LR-), receiver operating characteristic (ROC) curves, and areas under the ROC curves for the HCII test. We also considered alternative strategies, including Papanicolaou smear, a combination of Papanicolaou smear and the HCII test, a sequence of Papanicolaou smear followed by the HCII test, and a sequence of the HCII test followed by Papanicolaou smear. RESULTS: For the screening group, the sensitivity was 0.69 and the specificity was 0.93; the area under the ROC curve was 0.81. The LR+ and LR- were 10.24 and 0.34, respectively. For the diagnosis group, the sensitivity was 0.88 and the specificity was 0.78; the area under the ROC curve was 0.83. The LR+ and LR- were 4.06 and 0.14, respectively. Sequential testing showed little or no improvement over the combination testing. CONCLUSIONS: The HCII test in the screening group had a greater LR+ for the detection of CIN 2/3 or worse. HCII testing may be an additional screening tool for cervical cancer in women 30 years and older

    Atmosphere Assessment for MARS Science Laboratory Entry, Descent and Landing Operations

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    On August 6, 2012, the Mars Science Laboratory rover, Curiosity, successfully landed on the surface of Mars. The Entry, Descent and Landing (EDL) sequence was designed using atmospheric conditions estimated from mesoscale numerical models. The models, developed by two independent organizations (Oregon State University and the Southwest Research Institute), were validated against observations at Mars from three prior years. In the weeks and days before entry, the MSL "Council of Atmospheres" (CoA), a group of atmospheric scientists and modelers, instrument experts and EDL simulation engineers, evaluated the latest Mars data from orbiting assets including the Mars Reconnaissance Orbiter's Mars Color Imager (MARCI) and Mars Climate Sounder (MCS), as well as Mars Odyssey's Thermal Emission Imaging System (THEMIS). The observations were compared to the mesoscale models developed for EDL performance simulation to determine if a spacecraft parameter update was necessary prior to entry. This paper summarizes the daily atmosphere observations and comparison to the performance simulation atmosphere models. Options to modify the atmosphere model in the simulation to compensate for atmosphere effects are also presented. Finally, a summary of the CoA decisions and recommendations to the MSL project in the days leading up to EDL is provided

    Fullerene up-take alters bilayer structure and elasticity: A small angle X-ray study.

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    The coupling of fullerene (C60) to the structure and elasticity of 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine bilayers has been explored by synchrotron small angle X-ray scattering. Multilamellar vesicles were loaded with 0, 2 and 10mol.% of C60 and studied in a temperature range from 15 to 65°C. The addition of C60 caused an increase in the bilayer undulations (∼20%), in the bilayer separation (∼15%), in the linear expansion coefficient and caused a drop in the bending rigidity of the bilayers (20-40%). Possible damaging effects of fullerene on biomembranes are mainly discussed on the basis of altered bilayer fluidity and elasticity changes
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