176 research outputs found
Extension of effort for lunar flight handbook detailed technical report
Lunar flight handbook - orbital departure windows, libration points, and lunar flight orbit estimation, theory, and operation
Signal transduction in bacteria: CheW forms a reversible complex with the protein kinase CheA.
Complete metamorphosis in Manduca sexta involves specific changes in DNA methylation patterns
Student Perceptions of Age and Ageing-An Evaluation of Swiss Dental Students Receiving Education in Gerodontology
Society is ageing and the higher number of senior citizens in the total population is a challenge for society and often perceived as a burden. Negative images of old age can lead to ageism and poorer healthcare for older people. The younger generation will have to master these demographic challenges. Therefore, their attitude towards and their perception of the older generation has to be monitored. The aim of this study is to present the images of ageing held by dental students who received education in gerodontology and to assess possible changes between different generations of students over time and separated by gender. An annual, anonymous questionnaire survey was conducted among dental students at the end of the 10th semester each year between 2008 and 2021. The questionnaire surveyed personal attitudes towards ageing, the assessment of seniors, and personal experience with seniors (images of ageing, "Aging Semantic Differential"). In addition to confirming Friedan's phenomenon regarding the assessment of age limits, the present study was able to demonstrate a positive image of ageing in dental students, which has remained almost constant over the years. An education in gerodontology might positively influence student perceptions of age and aging
Application of Large-Scale Synthetic Power System Models for Energy Economic Studies
Due to information confidentiality issues, there is limited access to actual power system models that represent features of actual power grids for teaching, training, and research purposes. The authors\u27 previous work describes the process of creating synthetic transmission networks, with statistics similar to those of actual power grids. Thus, this paper outlines a systematic methodology to augment the synthetic network base case for energy economic studies. The key step is to determine generator cost models by fuel type and capacity. Based on statistics summarized from the actual grids, two approaches are proposed to assign coefficients to generator cost models. To illustrate the proposed creation procedure, we describe the construction of a synthetic model for Electric Reliability Council of Texas footprint. Simulation results are presented to verify that the created test system is able to represent the behavior of actual power systems
An Automated Visual Inspection System for the Classification of the Phases of Ti-6Al-4V Titanium Alloy
Metallography is the science of studying the physical properties of metal microstructures, by means of microscopes. While traditional approaches involve the direct observation of the acquired images by human experts, Com-puter Vision techniques may help experts in the analysis of the inspected mate-rials. In this paper we present an automated system to classify the phases of a Titanium alloy, Ti-6Al-4V. Our system has been tested to analyze the final products of a Friction Stir Welding process, to study the states of the micro-structures of the welded material
Electronic structure of SrPt_4Ge_{12}: a combined photoelectron spectroscopy and band structure study
We present a combined study of the electronic structure of the
superconducting skutterudite derivative SrPt4Ge12 by means of X-ray
photoelectron spectroscopy and full potential band structure calculations
including an analysis of the chemical bonding. We establish that the states at
the Fermi level originate predominantly from the Ge 4p electrons and that the
Pt 5d shell is effectively full. We find excellent agreement between the
measured and the calculated valence band spectra, thereby validating that band
structure calculations in combination with photoelectron spectroscopy can
provide a solid basis for the modeling of superconductivity in the compounds
MPt4Ge12 (M = Sr, Ba, La, Pr) series
Phosphorylation Alters the Interaction of the Arabidopsis Phosphotransfer Protein AHP1 with Its Sensor Kinase ETR1
The ethylene receptor ethylene response 1 (ETR1) and the Arabidopsis histidine-containing phosphotransfer protein 1 (AHP1) form a tight complex in vitro. According to our current model ETR1 and AHP1 together with a response regulator form a phosphorelay system controlling the gene expression response to the plant hormone ethylene, similar to the two-component signaling in bacteria. The model implies that ETR1 functions as a sensor kinase and is autophosphorylated in the absence of ethylene. The phosphoryl group is then transferred onto a histidine at the canonical phosphorylation site in AHP1. For phosphoryl group transfer both binding partners need to form a tight complex. After ethylene binding the receptor is switched to the non-phosphorylated state. This switch is accompanied by a conformational change that decreases the affinity to the phosphorylated AHP1. To test this model we used fluorescence polarization and examined how the phosphorylation status of the proteins affects formation of the suggested ETR1âAHP1 signaling complex. We have employed various mutants of ETR1 and AHP1 mimicking permanent phosphorylation or preventing phosphorylation, respectively. Our results show that phosphorylation plays an important role in complex formation as affinity is dramatically reduced when the signaling partners are either both in their non-phosphorylated form or both in their phosphorylated form. On the other hand, affinity is greatly enhanced when either protein is in the phosphorylated state and the corresponding partner in its non-phosphorylated form. Our results indicate that interaction of ETR1 and AHP1 requires that ETR1 is a dimer, as in its functional state as receptor in planta
- âŠ