2,110 research outputs found
Shuttle S-band communications technical concepts
Using the S-band communications system, shuttle orbiter can communicate directly with the Earth via the Ground Spaceflight Tracking and Data Network (GSTDN) or via the Tracking and Data Relay Satellite System (TDRSS). The S-band frequencies provide the primary links for direct Earth and TDRSS communications during all launch and entry/landing phases of shuttle missions. On orbit, S-band links are used when TDRSS Ku-band is not available, when conditions require orbiter attitudes unfavorable to Ku-band communications, or when the payload bay doors are closed. the S-band communications functional requirements, the orbiter hardware configuration, and the NASA S-band communications network are described. The requirements and implementation concepts which resulted in techniques for shuttle S-band hardware development discussed include: (1) digital voice delta modulation; (2) convolutional coding/Viterbi decoding; (3) critical modulation index for phase modulation using a Costas loop (phase-shift keying) receiver; (4) optimum digital data modulation parameters for continuous-wave frequency modulation; (5) intermodulation effects of subcarrier ranging and time-division multiplexing data channels; (6) radiofrequency coverage; and (7) despreading techniques under poor signal-to-noise conditions. Channel performance is reviewed
Nonverbale Synchronie und Musik-Erleben im klassischen Konzert
Die Praxis der Musikrezeption im Rahmen klassischer Konzerte ist von restriktiven Verhaltenskonventionen geprĂ€gt. Aktuelle kognitionswissenschaftliche und philosophische AnsĂ€tze, welche Musik-Erleben als verkörpert oder als ĂŒber mehrere Individuen verteilt konzeptualisieren, scheinen daher fĂŒr die ErklĂ€rung des Musik-Erlebens in klassischen Konzerten weniger geeignet. Vor diesem Hintergrund untersuchte die vorliegende explorative Studie das Auftreten koordinierter Körperbewegungen als nonverbale Synchronie im Rahmen eines klassischen Konzertes und den Zusammenhang zwischen den Synchronien innerhalb des Publikums und Aspekten des subjektiven Musik-Erlebens. Im Rahmen eines Forschungskonzerts wurden 22 Teilnehmern verschiedene Kammermusikwerke prĂ€sentiert, sowie dabei SelbstauskĂŒnfte zu Aspekten des Musik-Erlebens erhoben und Körperbewegungen mit drei stationĂ€ren Kameras erfasst. Nonverbale Synchronie, als Indikator fĂŒr koordinierte Körperbewegungen, wurde ĂŒber die Korrelation von Bewegungsenergie-Zeitreihen ermittelt. Die Bewegungsenergie wurde als Anzahl der sich Ă€ndernden Pixel aufeinanderfolgender Frames operationalisiert. Es zeigte sich stark ausgeprĂ€gte Synchronie zwischen den Musikern sowie eine Synchronie kleiner bis mittlerer EffektstĂ€rke innerhalb des Publikums. Zwischen den Musikern und dem Publikum konnte hingegen keine Synchronie festgestellt werden. In Bezug auf das VerhĂ€ltnis von Synchronie innerhalb des Publikums und dem subjektiven Musik-Erleben zeigten sich signifikante negative ZusammenhĂ€nge zwischen dem GefĂŒhl der Verbundenheit mit den Musikern, dem Grad der Absorption und der Synchronisierung innerhalb des Publikums. Dies lĂ€sst sich dahingehend interpretieren, dass bei einem stĂ€rkeren Fokus der Aufmerksamkeit und des Erlebens auf das BĂŒhnengeschehen die Synchronisierung mit den anderen Mitgliedern des Publikums abnimmt. Die Ergebnisse dieser Studie stehen im Einklang mit Theorien zum verkörperten Musik-Erleben, sie stĂŒtzen jedoch AnsĂ€tze nicht, die darunter die Nachahmung der klangproduzierenden Bewegungen der Musiker verstehen. Ebenso stehen die Befunde nicht in Einklang mit AnsĂ€tzen zum verteilten Musik-Erleben. AbschlieĂend werden die Ergebnisse hinsichtlich ihrer musikpraktischen Relevanz bezĂŒglich einer Diversifizierung klassischer Konzerte diskutiert
Leaf Temperatures in a Gas Exchange Chamber and in the Open Air
Leaf temperatures in a Koch fully climatized gas-exchange chamber as designed by Siemens and in a similarly equipped open-air reference were measured with horizontally and vertically inserted thermocouples on Nerium oleander L. On a sunny day with only little air movement and an average air temperature of 20.4 °C, leaf over-temperatures in the gas-exchange chamber were lower on average by 2.2 K. The extent of reduction of over-temperature in the chamber is determined by the reduced global radiation in the chamber and the differences of wind velocities in chamber and reference. Differences in the ventilation intensity in the chamber have no demonstrable influence on the leaf over-temperatures. The over-temperatures of the reference leaves, on the other hand, depend to a large degree on air velocity. The changed radiation and air flow conditions in the chamber as compared with open-air conditions have consequences for the physiological reactions of the enclosed plant and must be taken into account when comparing results from gas-exchange measurements with open-air conditions. For further improvements of gas-exchange measurement equipment, air flow conditions and radiation quantity and quality might be starting point
Preparing for the Rookie Year: Lessons from Those Who Have Gone Before
Christian business faculty prepare students for careers in the marketplace. But do they do enough to help students with their crucial rookie year in business? This paper proposes that faculty could do more and that the place to begin is to learn from the experiences of prior rookies. It provides an overview on the process of organizational entry and the lives of Christians in business as well as data from interviews of recent Christian college graduates who have entered the business world. The essay highlights dozens of stories of their experiences during their rookie years. Consideration is then turned to how faculty can use this information in their teaching and advising to help facilitate studentsâ transition from college to corporation. Finally, implications for future research are discussed
Not even the past: The joint influence of former leader and new leader during leader successions in the midst of organizational change
Leader succession often occurs during organizational change processes, but the implications of leader succession, in terms of reactions to the change, rarely have been investigated. Employee attitudes and behaviors during organizational change may be influenced jointly by a former leader who recently has transitioned out of the team and the new leader who recently has transitioned into it. We predict an interaction between former and new leadersâ transformational leadership on employeesâ behavioral resistance to and support for change. Based on contrast effect theory, a highly transformational former leader constrains the potential effectiveness of the new leader, but a former leader low in transformational leadership enhances this potential effectiveness. We also propose conditional indirect effects transmitted through commitment to the changing organization. Our research was conducted in a large Chinese hospitality organization that was implementing radical organizational change, during which virtually all aspects of processes and products are changed. We collected a 2-wave multisource data from employees who had recently experienced a leader succession and their newly assigned leaders. Based on a final sample of 203 employees from 22 teams, we find empirical support for the proposed interaction effects. The conditional indirect effects were also consistent with our expectations, but the effect on behavioral resistance to change was stronger than the effect on behavioral support for change.postprin
Dynamics of surface steps
In the framework of SOS models, the dynamics of isolated and pairs of surface
steps of monoatomic height is studied, for step--edge diffusion and for
evaporation kinetics, using Monte Carlo techniques. In particular, various
interesting crossover phenomena are identified. Simulational results are
compared, especially, to those of continuum theories and random walk
descriptions.Comment: 13 pages in elsart style, 4 eps figures, submitted to Physica
A contiuum model for low temperature relaxation of crystal steps
High and low temperature relaxation of crystal steps are described in a
unified picture, using a continuum model based on a modified expression of the
step free energy. Results are in agreement with experiments and Monte Carlo
simulations of step fluctuations and monolayer cluster diffusion and
relaxation. In an extended model where mass exchange with neighboring terraces
is allowed, step transparency and a low temperature regime for unstable step
meandering are found.Comment: Submitted to Phys.Rev.Let
A Novel Modelling Process in Chemistry: Merging Biological and Mathematical Perspectives to Develop Modelling Competences
Models are essential in science and therefore in scientific literacy. Therefore, pupils need to
attain competency in the appropriate use of models. This so-called modelâmethodical competence
distinguishes between model competence (the conceptual part) and modelling competence (the
procedural part), wherefrom a definition follows a general overview of the concept of models in this
article. Based on this, modelling processes enable the promotion of the modelling competence. In this
context, two established approaches mainly applied in other disciplines (biology and mathematics)
and a survey among chemistry teachers and employees of chemistry education departments (N = 98)
form the starting point for developing a chemistry modelling process. The article concludes with
a description of the developed modelling process, which by its design, provides an opportunity to
develop studentsâ modelling competence
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