Strategic Asset Seeking and Innovation Performance: The Role of Innovation Capabilities and Host Country Institutions

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PSR B1828-11: a precession pulsar torqued by a quark planet?

The pulsar PSR B1828-11 has long-term, highly periodic and correlated variations in both pulse shape and the rate of slow-down. This phenomenon may provide evidence for precession of the pulsar as suggested previously within the framework of free precession as well as forced one. On a presumption of forced precession, we propose a quark planet model to this precession henomenon instead, in which the pulsar is torqued by a quark planet. We construct this model by constraining mass of the pulsar ($M_{\rm psr}$), mass of the planet ($M_{\rm pl}$) and orbital radius of the planet ($r_{\rm pl}$). Five aspects are considered: derived relation between $M_{\rm psr}$ and $r_{\rm pl}$, movement of the pulsar around the center of mass, ratio of $M_{\rm psr}$ and $M_{\rm pl}$, gravitational wave radiation timescale of the planetary system, and death-line criterion. We also calculate the range of precession period derivative and gravitational wave strength (at earth) permitted by the model. Under reasonable parameters, the observed phenomenon can be understood by a pulsar ($10^{-4}\sim10^{-1}M_{\odot}$) with a quark planet ($10^{-8}\sim10^{-3}M_{\odot}$) orbiting it. According to the calculations presented, the pulsar would be a quark star because of its low mass, which might eject a lump of quark matter (to become a planet around) during its birth.Comment: 6 pages, 3 figures, accepted by MNRAS (Letters

Deformation of skull bone as intracranial pressure changing

Raised intracranial pressure (ICP), a serious and often fatal condition, is often not preventable. In the present study, the relationship was determined between cranial deformation and ICP change. To recordthe deformation of skull bone, strain foil was placed on the exterior surface of parietal skull. Prior to construction of finite-element model (FEM), using the rats, an in vivo study was undertaken. Threeanesthetized adult rats were subjected to baseline recording followed by either experimental raising ICP. By using the ‘Ansys’ finite element processor, a three-dimensional FEM of a hollow sphere wasconstructed for human skull. The model was used to calculate the deformation of human skull with the intracranial pressure changing. The skull is a layered sphere constructed in a specially designed formwith a Tabula externa, Tabula interna, and a porous Diploe sandwiched in between. The stress and strain deformations were well-proportional on the exterior surface of human skull. The deformation scope of human skull was theoretically from 1.0 to 3.4 with the changing ICP from 1.5 to 5.0 kPa. The cranium could move and human skull - dura mater system was deformed as the ICP fluctuates

Numerical modeling study of the momentum deposition of small amplitude gravity waves in the thermosphere

We study the momentum deposition in the thermosphere from the dissipation of small amplitude gravity waves (GWs) within a wave packet using a fully nonlinear two-dimensional compressible numerical model. The model solves the nonlinear propagation and dissipation of a GW packet from the stratosphere into the thermosphere with realistic molecular viscosity and thermal diffusivity for various Prandtl numbers. The numerical simulations are performed for GW packets with initial vertical wavelengths (&lambda;_<i>z</i>) ranging from 5 to 50 km. We show that &lambda;_<i>z</i> decreases in time as a GW packet dissipates in the thermosphere, in agreement with the ray trace results of Vadas and Fritts (2005) (VF05). We also find good agreement for the peak height of the momentum flux (<i>z</i>_diss) between our simulations and VF05 for GWs with initial &lambda;_<i>z</i> &le; 2&pi; <i>H</i> in an isothermal, windless background, where <i>H</i> is the density scale height. We also confirm that <i>z</i>_diss increases with increasing Prandtl number. We include eddy diffusion in the model, and find that the momentum deposition occurs at lower altitudes and has two separate peaks for GW packets with small initial &lambda;_<i>z</i>. We also simulate GW packets in a non-isothermal atmosphere. The net &lambda;_<i>z</i> profile is a competition between its decrease from viscosity and its increase from the increasing background temperature. We find that the wave packet disperses more in the non-isothermal atmosphere, and causes changes to the momentum flux and &lambda;_<i>z</i> spectra at both early and late times for GW packets with initial &lambda;_<i>z</i> &ge; 10 km. These effects are caused by the increase in <i>T</i> in the thermosphere, and the decrease in <i>T</i> near the mesopause

Statistical analysis on spatial correlation of ionospheric day-to-day variability by using GPS and Incoherent Scatter Radar observations

In this paper, the spatial correlations of ionospheric day-to-day variability are investigated by statistical analysis on GPS and Incoherent Scatter Radar observations. The meridional correlations show significant (&amp;gt;0.8) correlations in the latitudinal blocks of about 6 degrees size on average. Relative larger correlations of TEC&apos;s day-to-day variabilities can be found between magnetic conjugate points, which may be due to the geomagnetic conjugacy of several factors for the ionospheric day-to-day variability. The correlation coefficients between geomagnetic conjugate points have an obvious decrease around the sunrise and sunset time at the upper latitude (60&amp;deg;) and their values are bigger between the winter and summer hemisphere than between the spring and autumn hemisphere. The time delay of sunrise (sunset) between magnetic conjugate points with a high dip latitude is a probable reason. Obvious latitude and local time variations of meridional correlation distance, latitude variations of zonal correlation distance, and altitude and local time variations of vertical correlation distance are detected. Furthermore, there are evident seasonal variations of meridional correlation distance at higher latitudes in the Northern Hemisphere and local time variations of zonal correlation distance at higher latitudes in the Southern Hemisphere. These variations can generally be interpreted by the variations of controlling factors, which may have different spatial scales. The influences of the occurrence of ionospheric storms could not be ignored. Further modeling and data analysis are needed to address this problem. We suggest that our results are useful in the specific modeling/forecasting of ionospheric variability and the constructing of a background covariance matrix in ionospheric data assimilation

Probing neutral top-pion via a flavor-changing process γγ→tcˉΠt0\gamma\gamma\to t\bar{c}\Pi_{t}^{0}

In the framework of topcolor-assisted-technicolor model(TC2), we study a flavor-changing neutral top-pion production process $\gamma\gamma\to t\bar{c}\Pi_{t}^{0}$. The study shows that there exists a resonance effect which can enhance the cross section up to a few fb even tens fb. For a yearly luminosity 100 $fb^{-1}$ at future linear colliders, there might be hundreds even thousands events to be produced. On the other hand, the background of such flavor-changing process is very clean due to the GIM mechanism in SM . With such sufficient events and clean background, neutral toppion could be detected at future linear colliders with high center of energy and luminosity. Our study provides a possible way to test TC2 model.Comment: 10 pages, 4 figures,has been accepted by Phys.Rev.