Parsec-scale jet properties of the gamma-ray quasar 3C 286

The quasar 3C~286 is one of two compact steep spectrum sources detected by the {\it Fermi}/LAT. Here, we investigate the radio properties of the parsec(pc)-scale jet and its (possible) association with the $\gamma$-ray emission in 3C~286. The Very Long Baseline Interferometry (VLBI) images at various frequencies reveal a one-sided core--jet structure extending to the southwest at a projected distance of $\sim$1 kpc. The component at the jet base showing an inverted spectrum is identified as the core, with a mean brightness temperature of $2.8\times 10^{9}$~K. The jet bends at about 600 pc (in projection) away from the core, from a position angle of $-135^\circ$ to $-115^\circ$. Based on the available VLBI data, we inferred the proper motion speed of the inner jet as $0.013 \pm 0.011$ mas yr$^{-1}$ ($\beta_{\rm app} = 0.6 \pm 0.5$), corresponding to a jet speed of about $0.5\,c$ at an inclination angle of $48^\circ$ between the jet and the line of sight of the observer. The brightness temperature, jet speed and Lorentz factor are much lower than those of $\gamma$-ray-emitting blazars, implying that the pc-scale jet in 3C~286 is mildly relativistic. Unlike blazars in which $\gamma$-ray emission is in general thought to originate from the beamed innermost jet, the location and mechanism of $\gamma$-ray emission in 3C~286 may be different as indicated by the current radio data. Multi-band spectrum fitting may offer a complementary diagnostic clue of the $\gamma$-ray production mechanism in this source.Comment: 9 pages, 4 figures, accept for publication in MNRA

Corrigendum: Wafer-scale two-dimensional semiconductors from printed oxide skin of liquid metals.

Nature Communications 8: Article number: 14482; published: 17 February 2017; Updated: 22 March 2017 The original version of this Article contained a typographical error in the spelling of the author Omid Kavehei, which was incorrectly given as Omid Kevehei. This has now been corrected in both the PDF and HTML versions of the Article.</jats:p

Acupuncture for stable angina pectoris: a systematic review protocol

Introduction Previous reviews indicate that the effect of acupuncture on stable angina pectoris (SAP) remains controversial. The results of trials published in the past 5 years may possibly change this situation, but an updated systematic review is not available. We therefore designed this study to systematically assess the efficacy and safety of acupuncture for treating SAP. Methods and analysis Nine online databases will be searched without language or publication status restrictions from their inception to September 2017. Randomised controlled trials that include patients with stable angina receiving acupuncture therapy versus a control group will be deemed eligible. The selection of studies, data extraction and risk of bias assessment will be carried out by two independent reviewers. Data synthesis will be performed using RevMan V.5.3 software with either a fixed effects model or random effects model, depending on the heterogeneity test. Evidence quality will be evaluated using the Grading of Recommendations Assessment, Development and Evaluation system. The efficacy–effectiveness spectrum for each included trial will be rated using the Rating of Included Trials on the Efficacy-effectiveness Spectrum tool. Outcomes of interest include the improvement of weekly angina attacks and reduction of nitroglycerin medication use after receiving acupuncture treatment, the incidence of cardiovascular events, heart rate variability, pain intensity measured on a visual analogue scale, total workload and exercise duration at peak exercise, safety and adverse events. A meta-analysis will be conducted if no considerable heterogeneity is detected. The results will be presented as risk ratios with 95% CIs for dichotomous data and weighted mean differences or standardised mean differences with 95% CIs for continuous data. Ethics and dissemination This systematic review will not involve private information from individuals or endanger their rights, and therefore does not necessarily require ethical approval. The results may be published in a peer-reviewed journal or disseminated in relevant conferences. Trial registration number CRD42015016201.published_or_final_versio

Compact Bright Radio-loud AGNs. III. A Large VLBA Survey at 43 GHz

We present the results from the 43 GHz Very Long Baseline Array (VLBA) observations of 124 compact radio-loud active galactic nuclei (AGNs) that were conducted between 2014 November and 2016 May. The typical dimensions of the restoring beam in each image are about 0.5 mas x 0.2 mas. The highest resolution of 0.2 mas corresponds to a physical size of 0.02 pc for the lowest redshift source in the sample. The 43 GHz very long baseline interferometry (VLBI) images of 97 AGNs are presented for the first time. We study the source compactness on milliarcsecond and submilliarcsecond scales, and suggest that 95 sources in our sample are suitable for future space VLBI observations. By analyzing our data supplemented with other VLBA AGN surveys from the literature, we find that the core brightness temperature increases with increasing frequency below a break frequency similar to 7 GHz, and decreases between similar to 7 and 240 GHz but increases again above 240 GHz in the rest frame of the sources. This indicates that the synchrotron opacity changes from optically thick to thin. We also find a strong statistical correlation between radio and gamma-ray flux densities. Our correlation is tighter than those in the literature derived from lower-frequency VLBI data, suggesting that the gamma-ray emission is produced more cospatially with the 43 GHz VLBA core emission. This correlation can also be extrapolated to the unbeamed AGN population, implying that a universal gamma-ray production mechanism might be at work for all types of AGNs

Giant enhancement in UV response of ZnO nanobelts by polymer surface-functionalization

High sensitivity photodetectors are of great significance in developing a new generation of optoelectronic devices in sensing, imaging, and other applications. In this Communication, highly sensitive UV detectors based on ZnO nanobelts (NBs) are achieved by polymer surface-functionalization. The UV-induced photoconductance in ZnO NBs increases by 5 orders of magnitude after functionalizing, using a polymer that exhibits large UV absorption. The huge increase in photoconductance is attributed to an electron-hole generation process as assisted by the energy states in the polymer. This study suggests that, by selecting polymers with different wavelengths of UV absorption, highly sensitive UV detectors with a large range of detection wavelengths can be fabricated using ZnO NBs

Hidden attractors in fundamental problems and engineering models

Recently a concept of self-excited and hidden attractors was suggested: an attractor is called a self-excited attractor if its basin of attraction overlaps with neighborhood of an equilibrium, otherwise it is called a hidden attractor. For example, hidden attractors are attractors in systems with no equilibria or with only one stable equilibrium (a special case of multistability and coexistence of attractors). While coexisting self-excited attractors can be found using the standard computational procedure, there is no standard way of predicting the existence or coexistence of hidden attractors in a system. In this plenary survey lecture the concept of self-excited and hidden attractors is discussed, and various corresponding examples of self-excited and hidden attractors are considered

Parametric Study on Dimensional Control of ZnO Nanowalls and Nanowires by Electrochemical Deposition

A simple electrochemical deposition technique is used to synthesize both two-dimensional (nanowall) and one-dimensional (nanowire) ZnO nanostructures on indium-tin-oxide-coated glass substrates at 70°C. By fine-tuning the deposition conditions, particularly the initial Zn(NO3)2·6H2O electrolyte concentration, the mean ledge thickness of the nanowalls (50–100 nm) and the average diameter of the nanowires (50–120 nm) can be easily varied. The KCl supporting electrolyte used in the electrodeposition also has a pronounced effect on the formation of the nanowalls, due to the adsorption of Cl− ions on the preferred (0001) growth plane of ZnO and thereby redirecting growth on the (100) and (20) planes. Furthermore, evolution from the formation of ZnO nanowalls to formation of nanowires is observed as the KCl concentration is reduced in the electrolyte. The crystalline properties and growth directions of the as-synthesized ZnO nanostructures are studied in details by glancing-incidence X-ray diffraction and transmission electron microscopy