Asymptotically Non-Static Kerr-deSitter Spacetime With No Event Horizon

We present our derivations for Kerr-deSitter metric in a proper comoving coordinate system.It asymptotically approaches to the deSitter metric in Robertson-walker form.This has been done by considring the stationary axially-symmetric spacetime in which motion of particle is integrable.That is the Hamilton-Jacobi and Klein-Gordon equations are separable.In this form it is asymptotically consistent with comoving frame.Comment: Title changed,revised arguments,results unchanged

Asymptotics of Transmit Antenna Selection: Impact of Multiple Receive Antennas

Consider a fading Gaussian MIMO channel with $N_\mathrm{t}$ transmit and $N_\mathrm{r}$ receive antennas. The transmitter selects $L_\mathrm{t}$ antennas corresponding to the strongest channels. For this setup, we study the distribution of the input-output mutual information when $N_\mathrm{t}$ grows large. We show that, for any $N_\mathrm{r}$ and $L_\mathrm{t}$, the distribution of the input-output mutual information is accurately approximated by a Gaussian distribution whose mean grows large and whose variance converges to zero. Our analysis depicts that, in the large limit, the gap between the expectation of the mutual information and its corresponding upper bound, derived by applying Jensen's inequality, converges to a constant which only depends on $N_\mathrm{r}$ and $L_\mathrm{t}$. The result extends the scope of channel hardening to the general case of antenna selection with multiple receive and selected transmit antennas. Although the analyses are given for the large-system limit, our numerical investigations indicate the robustness of the approximated distribution even when the number of antennas is not large.Comment: 6 pages, 4 figures, ICC 201

Percolation in Networks with Voids and Bottlenecks

A general method is proposed for predicting the asymptotic percolation threshold of networks with bottlenecks, in the limit that the sub-net mesh size goes to zero. The validity of this method is tested for bond percolation on filled checkerboard and "stack-of-triangle" lattices. Thresholds for the checkerboard lattices of different mesh sizes are estimated using the gradient percolation method, while for the triangular system they are found exactly using the triangle-triangle transformation. The values of the thresholds approach the asymptotic values of 0.64222 and 0.53993 respectively as the mesh is made finer, consistent with a direct determination based upon the predicted critical corner-connection probability.Comment: to appear, Physical Review E. Small changes from first versio

Serangga Hama Penggerek Batang Albizia Falcataria (L.) Fosb. Dan Variasi Tipe Serangannya

R. UBAIDILLAH & M. AMIR. 1987. The Stem Borer Insects Pest on Albizia talcataria (L.) FOSB.and its Variation of tvoe of the Damage. Suppl. Berita Biologi. 3 : 66 - 69. .The stem borer insect of Albizia falcataria causes not only damage of the trunk, but also reduce the quality of the wood.Control of the insects borer using silviculture method require knowledges about its nature, behaviour and other ecological factor.The study of damage to Albizia stand by insects borer was carried out at the Albizia plantation, Rancamaya, Bogor.Observation were made on the group stands of 2 - 3; 6 - 7 and 9-10 years old respectively.The results indicate the Albizia stand are attacked by two species of insect borer, namely Xystrocera festiva Pasc.(Coleoptera : Cerambycidae) and Arbela tetraonis Moore. (Lepidoptera : Arbelidae).X festiva attacked stands of all group categories, while A. tetraonis attacked only the young stands or the branches of old stands. The damage caused by X. festra is up to 20% of the period 8-10 years, while A tetraonis caused damage up to 30% of the same class

Shading and Smothering of Gamma Ray Bursts

The gamma ray burst (GRB) 980425 is distinctive in that it seems to be associated with supernova (SN) 1998bw, has no X-ray afterglow, and has a single peak light curve and a soft spectrum. The supernova is itself unusual in that its expansion velocity exceeds c/6. We suggest that many of these features can be accounted for with the hypothesis that we observe the GRB along a penumbral line of sight that contains mainly photons that have scattered off ejected baryons. The hypothesis suggests a baryon poor jet (BPJ) existing within a baryon rich outflow. The sharp distinction can be attributed to whether or not the magnetic field lines thread an event horizon. Such a configuration suggests that there will be some non-thermal acceleration of pick-up ex-neutrons within the BPJ. This scenario might produce observable spallation products and neutrinos.Comment: 7 pages, 2 figures, submitted to ApJ

NK cells as effectors of acquired immune responses: effector CD4+ T cell-dependent activation of NK cells following vaccination.

We characterized vaccine-induced cellular responses to rabies virus in naive adult volunteers. Contrary to current paradigms, we observed potent and prolonged in vitro NK cell cytokine production and degranulation responses after restimulation of PBMCs with inactivated rabies virus in vaccinated, but not in unvaccinated, individuals. This "recall" NK cell response was absolutely dependent on Ag-specific IL-2 from CD45RO(+) CD4(+) T cells as well as IL-12 and IL-18 from accessory cells. Importantly, NK cells represented over 70% of all IFN-gamma-secreting and degranulating cells in the first 12-18 h after virus rechallenge indicating they may be required for rapid control of infection after vaccination. Activation of NK cells may be a critical function of IL-2-secreting effector memory T cells. Although IL-2-dependent postvaccination NK cell activation has been reported previously, this is the first time the magnitude of this effect and its contribution to the overall vaccine-induced response has been appreciated and the mechanisms of NK activation postvaccination have been elucidated. Our data will allow standard protocols for evaluating vaccine-induced immunity to be adapted to assess NK cell effector responses

On Robustness of Massive MIMO Systems Against Passive Eavesdropping under Antenna Selection

In massive MIMO wiretap settings, the base station can significantly suppress eavesdroppers by narrow beamforming toward legitimate terminals. Numerical investigations show that by this approach, secrecy is obtained at no significant cost. We call this property of massive MIMO systems `secrecy for free' and show that it not only holds when all the transmit antennas at the base station are employed, but also when only a single antenna is set active. Using linear precoding, the information leakage to the eavesdroppers can be sufficiently diminished, when the total number of available transmit antennas at the base station grows large, even when only a fixed number of them are selected. This result indicates that passive eavesdropping has no significant impact on massive MIMO systems, regardless of the number of active transmit antennas.Comment: 7 pages, 2 figures; To be presented in IEEE Global Communications Conference (Globecom) 2018 in Abu Dhabi, UA

Optimal Number of Transmit Antennas for Secrecy Enhancement in Massive MIMOME Channels

This paper studies the impact of transmit antenna selection on the secrecy performance of massive MIMO wiretap channels. We consider a scenario in which a multi-antenna transmitter selects a subset of transmit antennas with the strongest channel gains. Confidential messages are then transmitted to a multi-antenna legitimate receiver while the channel is being overheard by a multi-antenna eavesdropper. For this setup, we approximate the distribution of the instantaneous secrecy rate in the large-system limit. The approximation enables us to investigate the optimal number of selected antennas which maximizes the asymptotic secrecy throughput of the system. We show that increasing the number of selected antennas enhances the secrecy performance of the system up to some optimal value, and that further growth in the number of selected antennas has a destructive effect. Using the large-system approximation, we obtain the optimal number of selected antennas analytically for various scenarios. Our numerical investigations show an accurate match between simulations and the analytic results even for not so large dimensions.Comment: 6 pages, 4 figures, IEEE GLOBECOM 201