947 research outputs found
Prioritization, Incentives, and Resource Use for Sustainable Dentistry: The EU PRUDENT Project
SPORTS, EXERCISE ONLINE? THE OPINION OF SPORT MAJORS ON THE NON-ATTENDANCE TUITION
Aim of the study: The aim of our research is to map out the new aspect of life, in one section of higher education, created by the epidemiological situation, to get to know the methodics used by the teachers of the two sport science institutes (ESI, STI) in our faculty, and get to know our student's opinion on the topic. Methods: We worked with our own questionnaire, which includes the following groups of questions: demographic data, questions about the students' availability of tools, students' opinions about the requirements, communication with the instructor, the completion of the courses, changes in their own learning habits and their physical and practical preparation capabilities. The members of sample was studied at the Eötvös Loránd University PPK in Szombathely and Budapest by students majoring in sport field. Results: No difficulties were reported by our students, 90% had adequate tools. Their workload was much higher than in previous periods, which was reflected in a strong increase in time spent with studying (p <0.01). The lessons, tasks and dissertations carried out in the online learning space were a bigger challenge for the lecturers, based on the opinion of our students, the education did not seem more exciting or creative (2.8 on a 6-point scale). Opinions about the educational platforms used were evenly distributed, they did not find it difficult to navigate between the different surfaces (3.66 on a scale of 6.).Conclusion: The virtue of problem solving could be practiced in recent times. It is advisable to incorporate the experience of the recent period into the solutions of the important tasks aheadAim of the study: The aim of our research is to map out the new aspect of life, in one section of higher education, created by the epidemiological situation, to get to know the methodics used by the teachers of the two sport science institutes (ESI, STI) in our faculty, and get to know our student's opinion on the topic. Methods: We worked with our own questionnaire, which includes the following groups of questions: demographic data, questions about the students' availability of tools, students' opinions about the requirements, communication with the instructor, the completion of the courses, changes in their own learning habits and their physical and practical preparation capabilities. The members of sample was studied at the Eötvös Loránd University PPK in Szombathely and Budapest by students majoring in sport field. Results: No difficulties were reported by our students, 90% had adequate tools. Their workload was much higher than in previous periods, which was reflected in a strong increase in time spent with studying (p <0.01). The lessons, tasks and dissertations carried out in the online learning space were a bigger challenge for the lecturers, based on the opinion of our students, the education did not seem more exciting or creative (2.8 on a 6-point scale). Opinions about the educational platforms used were evenly distributed, they did not find it difficult to navigate between the different surfaces (3.66 on a scale of 6.).Conclusion: The virtue of problem solving could be practiced in recent times. It is advisable to incorporate the experience of the recent period into the solutions of the important tasks ahea
Experiment K-6-21. Effect of microgravity on 1) metabolic enzymes of type 1 and type 2 muscle fibers and on 2) metabolic enzymes, neutransmitter amino acids, and neurotransmitter associated enzymes in motor and somatosensory cerebral cortex. Part 1: Metabolic enzymes of individual muscle fibers; part 2: metabolic enzymes of hippocampus and spinal cord
The individual fibers of any individual muscle vary greatly in enzyme composition, a fact which is obscured when enzyme levels of a whole muscle are measured. The purpose of this study was therefore to assess the changes due to weightless on the enzyme patterns composed by the individual fibers within the flight muscles. In spite of the limitation in numbers of muscles examined, it is apparent that: (1) that the size of individual fibers (i.e., their dry weight) was reduced about a third, (2) that this loss in dry mass was accompanied by changes in the eight enzymes studied, and (3) that these changes were different for the two muscles, and different for the two enzyme groups. In the soleus muscle the absolute amounts of the three enzymes of oxidative metabolism decreased about in proportion to the dry weight loss, so that their concentration in the atrophic fibers was almost unchanged. In contrast, there was little loss among the four enzymes of glycogenolysis - glycolysis so that their concentrations were substantially increased in the atrophic fibers. In the TA muscle, these seven enzymes were affected in just the opposite direction. There appeared to be no absolute loss among the oxidative enzymes, whereas the glycogenolytic enzymes were reduced by nearly half, so that the concentrations of the first metabolic group were increased within the atrophic fibers and the concentrations of the second group were only marginally decreased. The behavior of hexokinase was exceptional in that it did not decrease in absolute terms in either type of muscle and probably increased as much as 50 percent in soleus. Thus, their was a large increase in concentration of this enzyme in the atrophied fibers of both muscles. Another clear-cut finding was the large increase in the range of activities of the glycolytic enzymes among individual fibers of TA muscles. This was due to the emergence of TA fibers with activities for enzymes of this group extending down to levels as low as those found in control soleus muscles. It would be interesting to know if this represents a transition stage, and whether with prolonged weightlessness most of the fibers would be transformed into a low glycogenolytic type
Nonlinear Analysis of the Space Shuttle Super-Lightweight External Fuel Tank
The results of buckling and nonlinear analyses of the Space Shuttle External Tank super-lightweight liquid oxygen (LOX) tank are presented. Modeling details and results are presented for two prelaunch loading conditions and for two full-scale structural tests conducted on the original external tank. These results illustrate three distinctly different types of nonlinear responses for thin-walled shells subjected to combined mechanical and thermal loads. These nonlinear response phenomena consist of bifurcation-type buckling, short-wavelength nonlinear bending, and nonlinear collapse associated with a limit point. For each case, the results show that accurate predictions of nonlinear behavior generally require a large scale high-fidelity finite element model. Results are also presented that show that a fluid filled launch vehicle shell can be highly sensitive to initial geometric imperfections. In addition, results presented for two full scale structural tests of the original standard weight external tank suggest that the finite element modeling approach used in the present study is sufficient for representing the nonlinear behavior of the super lightweight LOX tank
Excitonic fine structure and recombination dynamics in single-crystalline ZnO
The optical properties of a high quality bulk ZnO, thermally post treated in a forming gas environment are investigated by temperature dependent continuous wave and time-resolved photoluminescence (PL) measurements. Several bound and free exciton transitions along with their first excited states have been observed at low temperatures, with the main neutral-donor-bound exciton peak at 3.3605 eV having a linewidth of 0.7 meV and dominating the PL spectrum at 10 K. This bound exciton transition was visible only below 150 K, whereas the A-free exciton transition at 3.3771 eV persisted up to room temperature. A-free exciton binding energy of 60 meV is obtained from the position of the excited states of the free excitons. Additional intrinsic and extrinsic fine structures such as polariton, two-electron satellites, donor-acceptor pair transitions, and longitudinal optical-phonon replicas have also been observed and investigated in detail. Time-resolved PL measurements at room temperature reveal a biexponential decay behavior with typical decay constants of similar to170 and similar to864 ps for the as-grown sample. Thermal treatment is observed to increase the carrier lifetimes when performed in a forming gas environment
Interplay between pulsations and mass loss in the blue supergiant 55 Cygnus = HD 198478
Blue supergiant stars are known to display photometric and spectroscopic
variability that is suggested to be linked to stellar pulsations. Pulsational
activity in massive stars strongly depends on the star's evolutionary stage and
is assumed to be connected with mass-loss episodes, the appearance of
macroturbulent line broadening, and the formation of clumps in the wind. To
investigate a possible interplay between pulsations and mass-loss, we carried
out an observational campaign of the supergiant 55 Cyg over a period of five
years to search for photospheric activity and cyclic mass-loss variability in
the stellar wind. We modeled the H, He I, Si II and Si III lines using the
nonlocal thermal equilibrium atmosphere code FASTWIND and derived the
photospheric and wind parameters. In addition, we searched for variability in
the intensity and radial velocity of photospheric lines and performed a moment
analysis of the line profiles to derive frequencies and amplitudes of the
variations. The Halpha line varies with time in both intensity and shape,
displaying various types of profiles: P Cygni, pure emission, almost complete
absence, and double or multiple peaked. The star undergoes episodes of variable
mass-loss rates that change by a factor of 1.7-2 on different timescales. We
also observe changes in the ionization rate of Si II and determine a
multiperiodic oscillation in the He I absorption lines, with periods ranging
from a few hours to 22.5 days. We interpret the photospheric line variations in
terms of oscillations in p-, g-, and strange modes. We suggest that these
pulsations can lead to phases of enhanced mass loss. Furthermore, they can
mislead the determination of the stellar rotation. We classify the star as a
post-red supergiant, belonging to the group of alpha Cyg variables.Comment: 20 pages, 18 figures, 3 tables, accepted to Astronomy & Astrophysic
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Interpersonal distance theory of autism and its implication for cognitive assessment, therapy, and daily life
The interpersonal distance (IPD) theory provides a novel approach to studying autism spectrum disorder (ASD). In this article, we present recent findings on the neurobiological underpinnings of IPD regulation that are distinct in individuals with ASD. We also discuss the potential influence of environmental factors on IPD. We suggest that different IPD regulation may have implications for cognitive performance in experimental and diagnostic settings, may influence the effectiveness of training and therapy, and may play a role in the typical forms of social communication and leisure activities chosen by autistic individuals. We argue that reconsidering the results of ASD research through the lens of IPD would lead to a different interpretation of previous findings. Finally, we propose a methodological approach to study this phenomenon systematically
Development of Experimental Rocket for Component and Payload Acceleration Load Testing
With a burgeoning commercial space industry in the United States, more reliable and cost effective methods for qualifying critical flight components are required in order to reduce the costs of spacecraft development programs. Electronic payloads designed to undergo high acceleration loading during military and civil rocket flight have proven especially difficult to properly flight test prior to operational use. This paper describes the design, construction, flight testing, and post-flight analysis of a single stage launch vehicle with an intended apogee of 50,000 feet and maximum velocity in excess of Mach 2 with a simulated electronic payload. Software suites including OpenRocket, RasAero, and AeroFinSim were utilized in order to confirm rocket stability, a projected flight outline, and structural integrity of the airframe and fin composition/attachment that commonly fail during supersonic flight regimes. The airframe was primarily constructed of G12 filament wound fiberglass tubing in addition to a composite fin can centered around CNC’d G10 fiberglass cores with a wet carbon fiber layup by hand. Flight roll control was achieved via the onboard reaction wheel, which was constructed of 3D printed components and inertial measurement sensors. The completed vehicle experienced a successful flight to 42,000 ft, maximum velocity of Mach 2.2, and maximum acceleration of 16 G. The airframe and all components were safely recovered and in working order post-flight. A successful test of the simulated electronic payload was performed and a low cost flight verification method was established.https://digitalscholarship.unlv.edu/durep_podium/1025/thumbnail.jp
Orbital Magnetism and Current Distribution of Two-Dimensional Electrons under Confining Potential
The spatial distribution of electric current under magnetic field and the
resultant orbital magnetism have been studied for two-dimensional electrons
under a harmonic confining potential V(\vecvar{r})=m \omega_0^2 r^2/2 in
various regimes of temperature and magnetic field, and the microscopic
conditions for the validity of Landau diamagnetism are clarified. Under a weak
magnetic field (\omega_c\lsim\omega_0, \omega_c being a cyclotron frequency)
and at low temperature (T\lsim\hbar\omega_0), where the orbital magnetic
moment fluctuates as a function of the field, the currents are irregularly
distributed paramagnetically or diamagnetically inside the bulk region. As the
temperature is raised under such a weak field, however, the currents in the
bulk region are immediately reduced and finally there only remains the
diamagnetic current flowing along the edge. At the same time, the usual Landau
diamagnetism results for the total magnetic moment. The origin of this dramatic
temperature dependence is seen to be in the multiple reflection of electron
waves by the boundary confining potential, which becomes important once the
coherence length of electrons gets longer than the system length. Under a
stronger field (\omega_c\gsim\omega_0), on the other hand, the currents in
the bulk region cause de Haas-van Alphen effect at low temperature as
T\lsim\hbar\omega_c. As the temperature gets higher (T\gsim\hbar\omega_c)
under such a strong field, the bulk currents are reduced and the Landau
diamagnetism by the edge current is recovered.Comment: 15 pages, 11 figure
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