2,909 research outputs found
Exact solutions for vibrational levels of the Morse potential via the asymptotic iteration method
Exact solutions for vibrational levels of diatomic molecules via the Morse
potential are obtained by means of the asymptotic iteration method. It is shown
that, the numerical results for the energy eigenvalues of are all
in excellent agreement with the ones obtained before. Without any loss of
generality, other states and molecules could be treated in a similar way
Low cost antennas for MSAT vehicular applications
For Mobile MSAT applications a number of vehicular antennas have been developed that meet the program requirements. They are, however, costly to manufacture. Two antenna candidates are described here that provide adequate gain in the coverage zone and are also lower cost. One is the mast antenna that uses three or four element arrays of aquadrifilar helices. It generates omnidirectional pattern in azimuth and its beam is scanned in elevation. The second unit is a planar spiral antenna; it generates directional beams by a summation of the azimuthal modes. A variation of this antenna uses conical spirals to fulfill the same task. In both cases beam scanning is achieved by means of electronic switches rather than phase shifters, thus resulting in simpler configurations
Criterion for polynomial solutions to a class of linear differential equation of second order
We consider the differential equations y''=\lambda_0(x)y'+s_0(x)y, where
\lambda_0(x), s_0(x) are C^{\infty}-functions. We prove (i) if the differential
equation, has a polynomial solution of degree n >0, then \delta_n=\lambda_n
s_{n-1}-\lambda_{n-1}s_n=0, where \lambda_{n}=
\lambda_{n-1}^\prime+s_{n-1}+\lambda_0\lambda_{n-1}\hbox{and}\quad
s_{n}=s_{n-1}^\prime+s_0\lambda_{k-1},\quad n=1,2,.... Conversely (ii) if
\lambda_n\lambda_{n-1}\ne 0 and \delta_n=0, then the differential equation has
a polynomial solution of degree at most n. We show that the classical
differential equations of Laguerre, Hermite, Legendre, Jacobi, Chebyshev (first
and second kind), Gegenbauer, and the Hypergeometric type, etc, obey this
criterion. Further, we find the polynomial solutions for the generalized
Hermite, Laguerre, Legendre and Chebyshev differential equations.Comment: 12 page
Roles of binding elements, FOXL2 domains, and interactions with cJUN and SMADs in regulation of FSHβ.
We previously identified FOXL2 as a critical component in FSHβ gene transcription. Here, we show that mice deficient in FOXL2 have lower levels of gonadotropin gene expression and fewer LH- and FSH-containing cells, but the same level of other pituitary hormones compared to wild-type littermates, highlighting a role of FOXL2 in the pituitary gonadotrope. Further, we investigate the function of FOXL2 in the gonadotrope cell and determine which domains of the FOXL2 protein are necessary for induction of FSHβ transcription. There is a stronger induction of FSHβ reporter transcription by truncated FOXL2 proteins, but no induction with the mutant lacking the forkhead domain. Specifically, FOXL2 plays a role in activin induction of FSHβ, functioning in concert with activin-induced SMAD proteins. Activin acts through multiple promoter elements to induce FSHβ expression, some of which bind FOXL2. Each of these FOXL2-binding sites is either juxtaposed or overlapping with a SMAD-binding element. We determined that FOXL2 and SMAD4 proteins form a higher order complex on the most proximal FOXL2 site. Surprisingly, two other sites important for activin induction bind neither SMADs nor FOXL2, suggesting additional factors at work. Furthermore, we show that FOXL2 plays a role in synergistic induction of FSHβ by GnRH and activin through interactions with the cJUN component of the AP1 complex that is necessary for GnRH responsiveness. Collectively, our results demonstrate the necessity of FOXL2 for proper FSH production in mice and implicate FOXL2 in integration of transcription factors at the level of the FSHβ promoter
Telerobotics: A simulation facility for university research
An experimental telerobotics (TR) simulation suitable for studying human operator (H.O.) performance is described. Simple manipulator pick-and-place and tracking tasks allowed quantitative comparison of a number of calligraphic display viewing conditions. A number of control modes could be compared in this TR simulation, including displacement, rate and acceleratory control using position and force joysticks. A homeomorphic controller turned out to be no better than joysticks; the adaptive properties of the H.O. can apparently permit quite good control over a variety of controller configurations and control modes. Training by optimal control example seemed helpful in preliminary experiments. An introduced communication delay was found to produce decrease in performance. In considerable part, this difficulty could be compensated for by preview control information. That neurological control of normal human movement contains a data period of 0.2 second may relate to this robustness of H.O. control to delay. The Ames-Berkeley enhanced perspective display was utilized in conjunction with an experimental helmet mounted display system (HMD) that provided stereoscopic enhanced views
Quality of life of adolescents with cancer: family risks and resources
PURPOSE: The goal of this study was to evaluate the relative contribution of treatment intensity, family sociodemographic risk, and family resources to health-related quality of life (QOL) of 102 adolescents in treatment for cancer. METHODS: Adolescents and parents completed self-report measures of teen QOL, family functioning, and parent-child bonding. Based on parent report of family sociodemographic variables, an additive risk index was computed. A pediatric oncologist rated treatment intensity. RESULTS: Simultaneous regression analyses demonstrated the significant contribution of roles in family functioning and quality of parent-child relationship to prediction of psychosocial QOL (parent and teen-reported) as well as parent-reported teen physical QOL over and above the contribution of treatment intensity. Family sociodemographic risk did not contribute to QOL in these regression analyses. In additional analyses, specific diagnosis, types of treatment and individual sociodemographic risk variables were not associated with QOL. Parent and teen ratings of family functioning and quality of life were concordant. CONCLUSIONS: Family functioning, including quality of parent-child relationship, are central and potentially modifiable resistance factors in teen QOL while under treatment for cancer. Even more important than relying on diagnosis or treatment, screening for roles and relationships early in treatment may be an important aspect of determining risk for poor QOL outcomes
Flow behaviour of grains through the dosing station of spacecraft under low gravity environments
For the design of the grain-processing stations of spacecrafts, such as EXOMARS 2020, reliable estimates are required on the internal and bulk flow characteristics of granular media under the low gravitational environments. Using theoretical and computational modelling, here we present results on the generic flow behaviour of granular materials through flow channels under different gravity levels. For this, we use three approaches, viz., (i) a simple one-dimensional discrete layer approach (DLA) based on hybrid-Lagrange continuum analysis (ii) three dimensional Kirya structural continuum model and (iii) three dimensional discrete element modelling (DEM). Each model has its merits and limitations. For the granular simulant considered here, a good level of agreement is obtained between the results of Kirya model and DEM simulations on the flow properties of the grains. Some qualitative comparisons are also reported favourably on the flow characteristics of grains between the results of the experimental parabolic flight campaign and the DEM simulations. The theoretical and DEM simulations presented here could help to minimise relying on the complex experimental programmes, such as the parabolic flight campaign, for evaluating the processing behaviour of grains under low gravitational environments in future
Flow behaviour of grains through the dosing station of spacecraft under low gravity environments
For the design of the grain-processing stations of spacecrafts, such as EXOMARS 2020, reliable estimates are required on the internal and bulk flow characteristics of granular media under the low gravitational environments. Using theoretical and computational modelling, here we present results on the generic flow behaviour of granular materials through flow channels under different gravity levels. For this, we use three approaches, viz., (i) a simple one-dimensional discrete layer approach (DLA) based on hybrid-Lagrange continuum analysis (ii) three dimensional Kirya structural continuum model and (iii) three dimensional discrete element modelling (DEM). Each model has its merits and limitations. For the granular simulant considered here, a good level of agreement is obtained between the results of Kirya model and DEM simulations on the flow properties of the grains. Some qualitative comparisons are also reported favourably on the flow characteristics of grains between the results of the experimental parabolic flight campaign and the DEM simulations. The theoretical and DEM simulations presented here could help to minimise relying on the complex experimental programmes, such as the parabolic flight campaign, for evaluating the processing behaviour of grains under low gravitational environments in future
Any -state solutions of the Hulth\'en potential by the asymptotic iteration method
In this article, we present the analytical solution of the radial
Schr\"{o}dinger equation for the Hulth\'{e}n potential within the framework of
the asymptotic iteration method by using an approximation to the centrifugal
potential for any states. We obtain the energy eigenvalues and the
corresponding eigenfunctions for different screening parameters. The wave
functions are physical and energy eigenvalues are in good agreement with the
results obtained by other methods for different values. In order to
demonstrate this, the results of the asymptotic iteration method are compared
with the results of the supersymmetry, the numerical integration, the
variational and the shifted 1/N expansion methods.Comment: 14 pages and 1 figur
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