Non-existence of New Quantum Ergosphere Effect of a Vaidya-type Black Hole

Hawking evaporation of Dirac particles and scalar fields in a Vaidya-type black hole is investigated by the method of generalized tortoise coordinate transformation. It is shown that Hawking radiation of Dirac particles does not exist for $P_1, Q_2$ components but for $P_2, Q_1$ components in any Vaidya-type black holes. Both the location and the temperature of the event horizon change with time. The thermal radiation spectrum of Dirac particles is the same as that of Klein-Gordon particles. We demonstrates that there is no new quantum ergosphere effect in the thermal radiation of Dirac particles in any spherically symmetry black holes.Comment: Latex, 9 pages, no figure, submitted to Mod. Phys. Lett.

Functional Electrical Stimulation mediated by Iterative Learning Control and 3D robotics reduces motor impairment in chronic stroke

Background: Novel stroke rehabilitation techniques that employ electrical stimulation (ES) and robotic technologies are effective in reducing upper limb impairments. ES is most effective when it is applied to support the patients’ voluntary effort; however, current systems fail to fully exploit this connection. This study builds on previous work using advanced ES controllers, and aims to investigate the feasibility of Stimulation Assistance through Iterative Learning (SAIL), a novel upper limb stroke rehabilitation system which utilises robotic support, ES, and voluntary effort. Methods: Five hemiparetic, chronic stroke participants with impaired upper limb function attended 18, 1 hour intervention sessions. Participants completed virtual reality tracking tasks whereby they moved their impaired arm to follow a slowly moving sphere along a specified trajectory. To do this, the participants’ arm was supported by a robot. ES, mediated by advanced iterative learning control (ILC) algorithms, was applied to the triceps and anterior deltoid muscles. Each movement was repeated 6 times and ILC adjusted the amount of stimulation applied on each trial to improve accuracy and maximise voluntary effort. Participants completed clinical assessments (Fugl-Meyer, Action Research Arm Test) at baseline and post-intervention, as well as unassisted tracking tasks at the beginning and end of each intervention session. Data were analysed using t-tests and linear regression. Results: From baseline to post-intervention, Fugl-Meyer scores improved, assisted and unassisted tracking performance improved, and the amount of ES required to assist tracking reduced. Conclusions: The concept of minimising support from ES using ILC algorithms was demonstrated. The positive results are promising with respect to reducing upper limb impairments following stroke, however, a larger study is required to confirm this

Antiferromagnetic Domain Wall Engineering in Chromium Films

We have engineered an antiferromagnetic domain wall by utilizing a magnetic frustration effect of a thin iron cap layer deposited on a chromium film. Through lithography and wet etching we selectively remove areas of the Fe cap layer to form a patterned ferromagnetic mask over the Cr film. Removing the Fe locally removes magnetic frustration in user-defined regions of the Cr film. We present x-ray microdiffraction microscopy results confirming the formation of a 90{\deg} spin-density wave propagation domain wall in Cr. This domain wall nucleates at the boundary defined by our Fe mask.Comment: submitted to AP

Cyclic Universe with Quintom matter in Loop Quantum Cosmology

In this paper, we study the possibility of model building of cyclic universe with Quintom matter in the framework of Loop Quantum Cosmology. After a general demonstration, we provide two examples, one with double-fluid and another double-scalar field, to show how such a scenario is obtained. Analytical and numerical calculations are both presented in the paper.Comment: 11 pages, 2 figure

Task oriented Bayesian inference in interval timing: People use their prior reproduction experience to calibrate time reproduction

The estimation of duration has been shown to follow Bayesian inference, where people use their prior belief to calibrate the estimation. This explains timing biases such as the range bias where a duration is reproduced as longer when previously encountered durations were longer than shorter. However, it is unclear whether prior belief is based on previously perceived or reproduced durations. In 4 experiments, we show that the range bias occurs between short and long reproduction ranges but not between short and long perception ranges. Further analyses also show that the prior is updated by the most recent reproduced (but not perceived) duration. Together these results support a task-oriented Bayesian inference account of time reproduction, where people use the perceived duration and their past reproduction experience to make an inference about how much time to reproduce

Guest Editorial Special Issue on Graph-Powered Machine Learning for Internet of Things

Internet of Things (IoT) refers to an ecosystem where applications and services are driven by data collected from devices interacting with each other and the physical world. Although IoT has already brought spectacular benefits to human society, the progress is actually not as fast as expected. From network structures to control flow graphs, IoT naturally generates an unprecedented volume of graph data continuously, which stimulates fertilization and making use of advanced graph-powered methods on the diverse, dynamic, and large-scale graph IoT data

A maximum density rule for surfaces of quasicrystals

A rule due to Bravais of wide validity for crystals is that their surfaces correspond to the densest planes of atoms in the bulk of the material. Comparing a theoretical model of i-AlPdMn with experimental results, we find that this correspondence breaks down and that surfaces parallel to the densest planes in the bulk are not the most stable, i.e. they are not so-called bulk terminations. The correspondence can be restored by recognizing that there is a contribution to the surface not just from one geometrical plane but from a layer of stacked atoms, possibly containing more than one plane. We find that not only does the stability of high-symmetry surfaces match the density of the corresponding layer-like bulk terminations but the exact spacings between surface terraces and their degree of pittedness may be determined by a simple analysis of the density of layers predicted by the bulk geometric model.Comment: 8 pages of ps-file, 3 Figs (jpg

Human endogenous retrovirus K Rec forms a regulatory loop with MITF that opposes the progression of melanoma to an invasive stage

In the human genome, HERV-K(HML2) is the most recently endogenized retrovirus (ERV). While HERV-K(HML2) transcription is observed in healthy tissues, various cancers showed the upregulation of retroviral derived endogenized accessory products (e.g., envelope (Env), Np9 and Rec). Still, it is not clear whether the different HERV-K-derived genes contribute to a disease, or they are mere by-products. Here, we focus on the potential role of Rec in melanoma. Our in vitro model and high throughput data mining, including single-cell transcriptome analyses of patent’s material, reveal that Rec expression marks the proliferative (still controllable) stage of melanoma, and is involved in maintaining a delicate balance between cell proliferation and invasion. Thus, similar to melanocyte-inducing transcription factor (MITF), Rec is a sensitive marker of melanoma progression. Our Rec-knockdown in vitro system can faithfully model a subpopulation (MITF malignancy) of melanoma cells in human patients. Like Env, Rec modulates an endothelial-mesenchymal transition (EMT)-like process of cancer progression; however, they seem to affect the phenotype switch inversely. Rec inhibits the transition to the invasive state by altering the expression level of some key determinants of the EMT-like process, including MITF that directly binds the LTR5 _Hs of HERV-K. The Hominoid-specific HERV-K products might explain certain species-specific features of melanoma progression, and pinpoint to the limitation of using animal models in melanoma studies