Proactive edge caching in content-centric networks with massive dynamic content requests

Edge computing is a promising infrastructure evolution to reduce traffic loads and support low-latency communications. Furthermore, content-centric networks provide a natural solution to cache contents at edge nodes. However, it is a challenge for edge nodes to handle massive and highly dynamic content requests by users, and if without an efficient content caching strategy, the edge nodes will encounter high traffic load and latency due to increasing retrieval from content providers. This paper formulates a proactive edge caching problem to minimize the content retrieval cost at edge nodes. We exploit the inherent content caching and request aggregation mechanism in the content-centric networks to jointly minimize traffic load and content retrieval delay cost generated by the massive and dynamic content requests. We develop a Q-learning algorithm, which is an online optimal caching strategy, as it is adaptable to dynamic content popularity and content request intensity, and derive the long-term minimization of the content retrieval cost. Simulation results illustrate that the proposed algorithm can achieve a lower content retrieval cost compared with several baseline caching schemes

Tripartite efflux pumps: energy is required for dissociation, but not assembly or opening of the outer membrane channel of the pump

The MtrCDE multidrug pump, from Neisseria gonorrhoeae, is assembled from the inner and outer membrane proteins MtrD and MtrE, which are connected by the periplasmic membrane fusion protein MtrC. Although it is clear that MtrD delivers drugs to the channel of MtrE, it remains unclear how drug delivery and channel opening are connected. We used a vancomycin sensitivity assay to test for opening of the MtrE channel. Cells expressing MtrE or MtrE-E434K were insensitive to vancomycin; but became moderately and highly sensitive to vancomycin respectively, when coexpressed with MtrC, suggesting that the MtrE channel opening requires MtrC binding and is energy-independent. Cells expressing wild-type MtrD, in an MtrCE background, were vancomycin-insensitive, but moderately sensitive in an MtrCE-E434K background. The mutation of residues involved in proton translocation inactivated MtrD and abolished drug efflux, rendered both MtrE and MtrE-E434K vancomycin-insensitive; imply that the pump-component interactions are preserved, and that the complex is stable in the absence of proton flux, thus sealing the open end of MtrE. Following the energy-dependent dissociation of the tripartite complex, the MtrE channel is able to reseal, while MtrE-E434K is unable to do so, resulting in the vancomycin-sensitive phenotype. Thus, our findings suggest that opening of the OMP via interaction with the MFP is energy-independent, while both drug export and complex dissociation require active proton flux

'Functional' inspiratory and core muscle training enhances running performance and economy.

We compared the effects of two 6-week high-intensity interval training interventions. Under the control condition (CON), only interval training was undertaken, whilst under the intervention condition (ICT), interval training sessions were followed immediately by core training, which was combined with simultaneous inspiratory muscle training - 'functional' IMT. Sixteen recreational runners were allocated to either ICT or CON groups. Prior to the intervention phase, both groups undertook a 4-week programme of 'foundation' IMT to control for the known ergogenic effect of IMT [30 inspiratory efforts at 50% maximal static inspiratory pressure (P0) per set, 2 sets.d, 6 d.wk]. The subsequent 6-week interval running training phase, consisted of 3-4 sessions.wk. In addition, the ICT group undertook four inspiratory-loaded core exercises [10 repetitions.set, 2 sets.d, inspiratory load set at 50% post-IMT P0] immediately after each interval training session. The CON group received neither core training nor functional IMT. Following the intervention phase, global inspiratory and core muscle functions increased in both groups (P<0.05), as evidenced by P0 and a sport-specific endurance plank test performance (SEPT), respectively. Compared to CON, the ICT group showed larger improvements in SEPT, running economy at the speed of the OBLA, and 1-hr running performance (3.04% vs 1.57%, P<0.05). The changes in these variables were inter-individually correlated (r≥0.57, n=16, P<0.05). Such findings suggest that the addition of inspiratory-loaded core conditioning into a high-intensity interval training program augments the influence of the interval program upon endurance running performance, and that this may be underpinned by an improvement in running economy

Hawking Radiation as Quantum Tunneling in Rindler Coordinate

We substantiate the Hawking radiation as quantum tunneling of fields or particles crossing the horizon by using the Rindler coordinate. The thermal spectrum detected by an accelerated particle is interpreted as quantum tunneling in the Rindler spacetime. Representing the spacetime near the horizon locally as a Rindler spacetime, we find the emission rate by tunneling, which is expressed as a contour integral and gives the correct Boltzmann factor. We apply the method to non-extremal black holes such as a Schwarzschild black hole, a non-extremal Reissner-Nordstr\"{o}m black hole, a charged Kerr black hole, de Sitter space, and a Schwarzschild-anti de Sitter black hole.Comment: LaTex 19 pages, no figure; references added and replaced by the version accepted in JHE

Glucagonoma-induced acute heart failure

Neuroendocrine tumours (NETs) represent a broad spectrum of tumours, of which the serotonin-producing carcinoid is the most common and has been shown to cause right ventricular heart failure. However, an association between heart failure and NETs other than carcinoid has not been established so far. In this case report, we describe a 51-year-old patient with a glucagon-producing NET of the pancreas who developed acute heart failure and even cardiogenic shock despite therapy. Heart failure eventually regressed after initialising i.v. treatment with the somatostatin analogue octreotide. Chromogranin A as a tumour marker was shown to be significantly elevated, and it decreased with clinical improvement of the patient. The effects of long-time stimulation of glucagon on the myocardium have not been studied yet; however, sarcoplasmic reticulum calcium leak can be discussed as a possible mechanism for glucagon-induced heart failure

Evidence of microscopic effects in fragment mass distribution in heavy ion induced fusion-fission reactions

Our measurements of variances ($\sigma_{m}^2$) in mass distributions of fission fragments from fusion-fission reactions of light projectiles (C, O and F) on deformed thorium targets exhibit a sharp anomalous increase with energy near the Coulomb barrier, in contrast to the smooth variation of $\sigma_{m}^2$ for the spherical bismuth target. This departure from expectation based on a statistical description is explained in terms of microscopic effects arising from the orientational dependence in the case of deformed thorium targets.Comment: Replaced with revised version, to appear in Phys. Lett.

Low-energy Spectra of the t-J-Type Models Studied by Variational Approach

We discuss recent progress of understanding the phenomena observed in high Tc cuprates by studying the d-wave resonating-valence-bond (d-RVB) based trial wave functions for the 2-dimensional t-J-type models. Treat exactly the strong correlation between electrons by numerical approach, we examine the evolution of ground states described by different variational wave functions and properties of the quasi-hole and -particle excitations of the d-RVB superconducting (SC) state. Properties related to the Fermi surface geometry deduced from quasi-hole energy dispersion of the SC state is shown to be consistent with the observation by photoemission spectroscopy. With the calculated spectral weights (SW's) for adding and removing an electron, we found not only the anti-correlation between conductance peak height and width between peaks seen in tunneling experiments, but also unique properties due to strong correlation which need to be verified by future experiments.Comment: 6 revtex pages with 5 (.eps) figures. To appear in a special volume of Journal of Magnetism and Magnetic Materials for the ICM 2006 proceeding

Joint task scheduling and multi-UAV deployment for aerial computing in emergency communication networks

This article studies mobile edge computing technologies enabled by unmanned aerial vehicles (UAVs) in disasters. First, considering that the ground servers may be damaged in emergency scenarios, we proposed an air-ground cooperation architecture based on ad-hoc UAV networks. We defined the system cost as the weighted sum of task delay and energy consumption because of different delay sensitivity and energy sensitivity tasks in emergency communication networks. Then, we formulated the system cost-minimization problem of task scheduling and multi-UAV deployments. To solve the proposed mixed integer nonlinear programming problem, we decomposed it to two sub-problems that were solved by proposing a swap matching-based task scheduling sub-algorithm and a successive convex approximation-based multi-UAV deployment sub-algorithm. Accordingly, we propose a joint optimization algorithm by iterating the two sub-algorithms to obtain a low complexity sub-optimal solution. Finally, the simulation results show that (i) the proposed algorithm converges in several iterations, and (ii) compared with the benchmark algorithms, the proposed algorithm has better performance of reducing task delay and energy consumption and achieves a good trade-off between them for diverse tasks

ATIC and PAMELA Results on Cosmic e^\pm Excesses and Neutrino Masses

Recently the ATIC and PAMELA collaborations released their results which show the abundant e^\pm excess in cosmic rays well above the background, but not for the \bar{p}. Their data if interpreted as the dark matter particles' annihilation imply that the new physics with the dark matter is closely related to the lepton sector. In this paper we study the possible connection of the new physics responsible for the cosmic e^\pm excesses to the neutrino mass generation. We consider a class of models and do the detailed numerical calculations. We find that these models can natually account for the ATIC and PAMELA e^\pm and \bar{p} data and at the same time generate the small neutrino masses.Comment: 7 pages, 5 figures. Published version with minor corrections and more reference