588 research outputs found
Integrated Turbine-Based Combined Cycle Dynamic Simulation Model
A Turbine-Based Combined Cycle (TBCC) dynamic simulation model has been developed to demonstrate all modes of operation, including mode transition, for a turbine-based combined cycle propulsion system. The High Mach Transient Engine Cycle Code (HiTECC) is a highly integrated tool comprised of modules for modeling each of the TBCC systems whose interactions and controllability affect the TBCC propulsion system thrust and operability during its modes of operation. By structuring the simulation modeling tools around the major TBCC functional modes of operation (Dry Turbojet, Afterburning Turbojet, Transition, and Dual Mode Scramjet) the TBCC mode transition and all necessary intermediate events over its entire mission may be developed, modeled, and validated. The reported work details the use of the completed model to simulate a TBCC propulsion system as it accelerates from Mach 2.5, through mode transition, to Mach 7. The completion of this model and its subsequent use to simulate TBCC mode transition significantly extends the state-of-the-art for all TBCC modes of operation by providing a numerical simulation of the systems, interactions, and transient responses affecting the ability of the propulsion system to transition from turbine-based to ramjet/scramjet-based propulsion while maintaining constant thrust
P-Match: transcription factor binding site search by combining patterns and weight matrices
P-Match is a new tool for identifying transcription factor (TF) binding sites in DNA sequences. It combines pattern matching and weight matrix approaches thus providing higher accuracy of recognition than each of the methods alone. P-Match is closely interconnected with the TRANSFAC(®) database. In particular, P-Match uses the matrix library as well as sets of aligned known TF-binding sites collected in TRANSFAC(®) and therefore provides the possibility to search for a large variety of different TF binding sites. Using results of extensive tests of recognition accuracy, we selected three sets of optimized cut-off values that minimize either false negatives or false positives, or the sum of both errors. Comparison with the weight matrix approaches such as Match™ tool shows that P-Match generally provides superior recognition accuracy in the area of low false negative errors (high sensitivity). As familiar to the user of Match™, P-Match also allows to save user-specific profiles that include selected subsets of matrices with corresponding TF-binding sites or user-defined cut-off values. Furthermore, a number of tissue-specific profiles are provided that were compiled by the TRANSFAC(®) team. A public version of the P-Match tool is available at
Tree-based solvers for adaptive mesh refinement code FLASH -- III: a novel scheme for radiation pressure on dust and gas and radiative transfer from diffuse sources
Radiation is an important contributor to the energetics of the interstellar
medium, yet its transport is difficult to solve numerically. We present a novel
approach towards solving radiative transfer of diffuse sources via backwards
ray tracing. Here we focus on the radiative transfer of infrared radiation and
the radiation pressure on dust. The new module, \textsc{TreeRay/RadPressure},
is an extension to the novel radiative transfer method \textsc{TreeRay}
implemented in the grid-based MHD code {\sc Flash}. In
\textsc{TreeRay/RadPressure}, every cell and every star particle is a source of
infrared radiation. We also describe how gas, dust and radiation are coupled
via a chemical network. This allows us to compute the local dust temperature in
thermal equilibrium, leading to a significantly improvement over the classical
grey approximation. In several tests, we demonstrate that the scheme produces
the correct radiative intensities as well as the correct momentum input by
radiation pressure. Subsequently, we apply our new scheme to model massive star
formation from a collapsing, turbulent core of 150 . We trace
the effects of both, ionizing and infrared radiation on the dynamics of the
core. We find that the newborn massive star(s) prevent fragmentation in their
proximity through radiative heating. Over time, dust and radiation temperature
equalize, while the gas temperature can be either warmer due to shock heating
or colder due to insufficient dust-gas coupling. Compared to gravity, the
effects of radiation pressure become significant on the core scale only at an
evolved stage.Comment: 25 pages, 19 figures, submitted to MNRA
Pathways to paediatric urology subspecialisation:a study of casemix, incumbent attitudes and opinions
Objective: To identify any self-reported differences or attitudes towards certification, publication, or practice patterns between adult urology and paediatric general surgery-trained paediatric urology providers. There are no known published differences in clinical/operative/research outcomes in either group. Methods: An 18-item cross-sectional survey was compiled through the EAU Young Academic Urologists (YAU) office and disseminated to a trans-Atlantic convenience sample of current practising paediatric urologists. This was created using a mini-Delphi method to provide current semi-quantitative data relating to current opinions and attitudes of this cohort. Results: A total of 228 respondents completed the survey, with female respondents representing 37% and 34% for urology and paediatric general surgery, respectively. Nearly 90% overall respondents felt that a full 2-year paediatric fellowship program was very important and 94% endorsed a collaborative dedicated paediatric urology on call service, with 92% supporting the joint development of transitional care. Urology managed higher numbers of bedwetting (p = 0.04), bladder bowel dysfunction (p = 0.02), endourological procedures (p = 0.04), and robotics (p = 0.04). Paediatric general surgery managed higher numbers of laparoscopic reconstruction (p = 0.03), and posterior urethral valve ablation (p = 0.002). Conclusion: This study represents the first time that a cross-sectional cohort of paediatric urologists from different training backgrounds were compared to assess their productivity, practice patterns and attitudes. Paediatric urology is in a unique position to have two contributing specialities, with the ability to provide optimal transitional and lifelong care. We believe that there should be a strong emphasis on collaboration and to remove any historically-created barriers under policies of equity, diversity and inclusivity.</p
Mobility and Sporting Activity After Renal Trauma:A Survey Regarding Best Clinical Practice During the Recovery Stage
Objective: To evaluate strategies that are followed after pediatric renal trauma during the recovery stage, with an emphasis on mobility and involvement in subsequent sporting activities. Renal trauma is the most common urogenital trauma in children. The American Association for the Surgery of Trauma (AAST) scale is most commonly used to stratify the severity of injury. There is no consensus in the existing literature with respect to the recovery stage following renal trauma. Methods: A survey was constructed by the European Association of Urology (EAU) – Young Academic Urologists (YAU) Pediatric Urology Working Group and then made digitally available on SurveyMonkey. The survey consists of 15 questions exploring relevant factors and timing to start again with mobility and activity. Results: In total 153 people responded, of whom 107 completed the entire survey. The presence of pain and severity of trauma were acknowledged as most important factors to commence mobilization, whereas presence of hematuria was identified as an additional factor for sporting activity. Regardless of severity of trauma a minimum of 90% of respondents recommend return to noncontact sports within 12 weeks. For contact sports, a minimum of 33% of respondents advised >12 weeks minimum before starting again. A small number of respondents would never allow sporting activities again. Conclusion: The time to allow sporting activity shows high variation among the respondents, some even restricting sporting activities completely. This survey highlights the need for a standardized protocol based on multicenter follow-up data.</p
Ion acceleration from microstructured targets irradiated by high-intensity picosecond laser pulses
Structures on the front surface of thin foil targets for laser-driven ion acceleration have been proposed to increase the ion source maximum energy and conversion efficiency. While structures have been shown to significantly boost the proton acceleration from pulses of moderate-energy fluence, their performance on tightly focused and high-energy lasers remains unclear. Here, we report the results of laser-driven three-dimensional (3D)-printed microtube targets, focusing on their efficacy for ion acceleration. Using the high-contrast (∼1012) PHELIX laser (150J, 1021W/cm2), we studied the acceleration of ions from 1-μm-thick foils covered with micropillars or microtubes, which we compared with flat foils. The front-surface structures significantly increased the conversion efficiency from laser to light ions, with up to a factor of 5 higher proton number with respect to a flat target, albeit without an increase of the cutoff energy. An optimum diameter was found for the microtube targets. Our findings are supported by a systematic particle-in-cell modeling investigation of ion acceleration using 2D simulations with various structure dimensions. Simulations reproduce the experimental data with good agreement, including the observation of the optimum tube diameter, and reveal that the laser is shuttered by the plasma filling the tubes, explaining why the ion cutoff energy was not increased in this regime.Fil: Bailly Grandvaux, M.. University of California at San Diego; Estados UnidosFil: Kawahito, D.. University of California at San Diego; Estados UnidosFil: McGuffey, C.. University of California at San Diego; Estados UnidosFil: Strehlow, J.. University of California at San Diego; Estados UnidosFil: Edghill, B.. University of California at San Diego; Estados UnidosFil: Wei, M.S.. Laboratory For Laser Energetics; Estados UnidosFil: Alexander, N.. General Atomics; Estados UnidosFil: Haid, A.. General Atomics; Estados UnidosFil: Brabetz, C.. Helmholtzzentrum Für Schwerionenforschung; AlemaniaFil: Bagnoud, V.. Helmholtzzentrum Für Schwerionenforschung; AlemaniaFil: Hollinger, R.. State University of Colorado - Fort Collins; Estados UnidosFil: Capeluto, Maria Gabriela. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Física de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Física de Buenos Aires; ArgentinaFil: Rocca, J.J.. State University of Colorado - Fort Collins; Estados UnidosFil: Beg, F.N.. University of California at San Diego; Estados Unido
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PManalyzer: A Software Facilitating the Study of Sensorimotor Control of Whole-Body Movements
Motion analysis is used to study the functionality or dysfunctionality of the neuromuscular system, as human movements are the direct outcome of neuromuscular control. However, motion analysis often relies on measures that quantify simplified aspects of a motion, such as specific joint angles, despite the well-known complexity of segment interactions. In contrast, analyzing whole-body movement patterns may offer a new understanding of movement coordination and movement performance. Clinical research and sports technique evaluations suggest that principal component analysis (PCA) provides novel and valuable insights into control aspects of the neuromuscular system and how they relate to coordinative patterns. However, the implementation of PCA computations are time consuming, and require mathematical knowledge and programming skills, drastically limiting its application in current research. Therefore, the aim of this study is to present the Matlab software tool “PManalyzer” to facilitate and encourage the application of state-of-the-art PCA concepts in human movement science. The generalized PCA concepts implemented in the PManalyzer allow users to apply a variety of marker set independent PCA-variables on any kinematic data and to visualize the results with customizable plots. In addition, the extracted movement patterns can be explored with video options that may help testing hypotheses related to the interplay of segments. Furthermore, the software can be easily modified and adapted to any specific application
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