bluuebunny/crossref_metadata_2025_split huggingface dataset:
The starburst – active galactic nuclei connection on nuclear scales in near by Seyfert galaxies
Authors: Esquej Pilar 
Published: July 2014

AbstractSeveral works have shown that there is an empirical correlation between the star formation rate and the luminosity of the active galactic nucleus (and thus the black hole accretion rate, ṀBH) of Seyfert galaxies. This suggests a physical relation between the gas forming stars on kpc scales and the gas on sub-pc scales that is feeding the black hole. Simulations predict this relation and also that the correlation should be more prominent on smaller physical scales. We have compiled high angular resolution (0.4–0.8″) mid-infrared spectroscopy obtained with T-ReCS, VISIR, and Michelle of 29 Seyferts. We use the 11.3 μm PAH feature to probe the star formation activity in the inner ~65 pc, and its relation with the ṀBH on these physical scales.
Multiwavelength Study of Radio Loud Early-Type Galaxies from the B2 Sample
Authors: Sahu Sheetal Kumar , Chaware Laxmikant , Pandey S. K. , Kulkarni Samridhi , Pandge M. B. , Chakradhari N. K. 
Published: July 2014

AbstractWe present multiwavelength study of a sample of radio loud early-type galaxies chosen from the B2 sample. We performed surface photometry in BVR broad band filters and Hα narrow band filter on CCD images of sample galaxies using IGO 2m telescope, Pune (INDIA), to get radial profiles of various photometric and geometrical parameters that describe elliptical isophotes fitted to the 2D light distribution of the galaxies. The analysis of radial profiles of quantities such as the (local) surface brightness, the ellipticity, and the deviations from elliptical isophotes parametrized by the Fourier coefficients are main focus of our study. We generated color maps, residual maps, and dust extinction maps, Hα emission maps of the galaxies to study the morphology of the dust and ionized gas content present in the galaxies. We carried out detailed analysis of the properties of the dust present in our sample galaxies. Additionaly, we investigated properties of the dust in the central ~10 arcsec region of our sample galaxies using optical images available from the HST (WFPC2) data archive. We estimated mass and temperature of the dust, molecular gas mass, in the sample galaxies using FIR fluxes of the galaxies obtained from IRAS.We used spectroscopic data available from the SDSS (DR7) to get an estimate of the mass of the central super massive black-hole for B2 1257+28 (NGC 4874). We plotted rotation curve for coma cluster (Abell 1656), which indicates the presence of dark matter halo around the galaxy B2 1257+28.
The Circumgalactic Medium of Quasars
Authors: Hennawi Joe 
Published: July 2014

AbstractI will argue that observations of the diffuse gas in the outskirts of quasar host galaxies, or the so called circumgalactic medium, are essential for understanding how luminous quasars evolve in a cosmological context. Such observations also provide a fruitful comparison to theory, because hydrodynamics at moderate overdensities is much easier to simulate than the complicated processes which trigger quasar activity. A novel technique will be introduced, whereby a foreground quasar can be studied in absorption against a background quasar, resolving scales as small as 30 kpc. This experiment reveals a rich absorption spectrum which contains a wealth of information about the physical conditions of diffuse gas around quasars. Hydrodynamical simulations of the massive dark matter halos which host luminous quasars under predict the amount of cool gas observed in quasar environs by a large factor, challenging our understanding of how massive galaxies form. I will also discuss a very sensitive search for Ly-alpha emission from the same gas which we study in absorption.
Compact nuclear objects and properties of their parent galaxies
Authors: Zasov Anatoly V. , Cherepashchuk Anatoly M. 
Published: July 2014

AbstractWe consider the relationship between the masses of the compact nuclear objects in the centers of disky galaxies – supermassive black holes (SMBHs) or nuclear star clusters (NCs) – and such parameters as the maximal velocity of rotation Vmax, obtained from the rotation curves, indicative dynamical mass M25, and the color index (B−V) of their parent galaxies. It was found that the mass of nuclear clusters Mnc correlates more closely with the velocity of rotation and total mass of galaxies than the mass of supermassive black holes Mbh. The dependence of masses of the central objects on the color index is bimodal: galaxies of the red group (red-sequence), which have (B−V) > 0.6−0.7, differ from bluer galaxies, by higher values of Mbh for similar host-galaxy parameters. In contrast, in the diagrams for nuclear clusters the “blue” and “red” galaxies form unified sequences. It agrees with scenarios in which most red-group galaxies form as a result of loss of interstellar gas in a stage of high nuclear activity in galaxies whose central black-hole masses are high, exceeding 106 − 107M⊙ (depending on the total mass of the galaxy). The active growth of nuclear star clusters possibly begun after the violent AGN activity.
Using AGN Variability Surveys to explore the AGN-Galaxy Connection
Authors: Sarajedini Vicki L. 
Published: July 2014

AbstractVariability is a successful technique used to identify active galactic nuclei in both ground and space-based galaxy surveys. Optical variability surveys using HST have uncovered a number of AGN in deep extragalactic fields extending to z ~ 3 and probing intrinsically faint sources. Mid-IR variability surveys using Spitzer have identified a significant number of AGN and are particularly sensitive to obscured sources. Many variability-detected AGN are not strong X-ray sources or lack the characteristic colors of AGN and would thus be unidentified using other selection techniques. In this conference proceedings, I discuss the nature of the variable sources and their host galaxies identified in deep extragalactic optical and mid-IR surveys.
High redshift quasars monitoring campaign
Authors: Botti Ismael , Lira Paulina , Martinez Jorge , Netzer Hagai , Kaspi Shai 
Published: July 2014

AbstractWe present an update of the monitoring campaign we have undertaken to probe the most massive black holes in powerful quasars at high redshift through the reverberation mapping technique. Once this campaign has finished, we will be able to directly measure broad line region (BLR) sizes of quasars at z ~ 2−3, improving dramatically the BLR size-luminosity relation, and therefore, black hole mass estimates based on this relationship. So far, we have identified a dozen highly variable sources suitable for future cross-correlation analysis and reverberation measurements.
Large-scale structure studies with AGN in the eROSITA/SRG All-Sky Survey
Authors: Kolodzig Alexander , Gilfanov Marat , Hütsi Gert , Sunyaev Rashid 
Published: July 2014

AbstractThe four-year X-ray all-sky survey (eRASS) of the eROSITA telescope aboard the Spektrum-Roentgen-Gamma satellite will detect ~ 3 million active galactic nuclei (AGN) with a median redshift of z≈1. We show that this unprecedented AGN sample, complemented with redshift information, will supply us with outstanding opportunities for large-scale structure research. For the first time with a sample of X-ray selected AGN, it will become possible to perform detailed redshift- and luminosity-resolved studies of the linear bias factor, and to convincingly detected baryonic acoustic oscillations (BAOs). To exploit the full potential of the eRASS AGN sample, photometric and spectroscopic surveys of large areas and a sufficient depth will be needed.
Conference Summary
Authors: Sanders David B. 
Published: July 2014

AbstractThis conference on “Multi-wavelength AGN Surveys and Studies” has provided a detailed look at the explosive growth over the past decade, of available astronomical data from a growing list of large scale sky surveys, from radio-to-gamma rays. We are entering an era were multi-epoch (months to weeks) surveys of the entire sky, and near-instantaneous follow-up observations of variable sources, are elevating time-domain astronomy to where it is becoming a major contributor to our understanding of Active Galactic Nuclei (AGN). While we can marvel at the range of extragalactic phenomena dispayed by sources discovered in the original “Markarian Survey” – the first large-scale objective prism survey of the Northern Sky carried out at the Byurakan Astronomical Observtory almost a half-century ago – it is clear from the talks and posters presented at this meeting that the data to be be obtained over the next decade will be needed if we are to finally understand which phase of galaxy evolution each Markarian Galaxy represents.
Analysis of Au metal–metal contacts in a lateral actuated RF MEMS switch
Authors: Gaitzsch Markus , Kurth Steffen , Voigt Sven , Haas Sven , Gessner Thomas 
Published: July 2014

This paper reports on the ohmic contacts of an radio-frequency micro-electro-mechanical-system (RF MEMS) switch. The structure of the MEMS is described briefly to give information about the organization of the switch device. The most significant performance data are reported, indicating very low actuation voltage below 5 V, switching time of <10 µs and good RF performance for frequencies up to 5 GHz. Since the contact performance is a key for excellent RF performance in the actuated state and for high reliability as well the article is focused on the contacts. It is supposed that asperities are building the current path in a closed contact, which is proved by measurements of the closing process with high time resolution. The measurements exhibit very good power-handling capabilities of the contacts. The reported findings render prior theoretical experiments with a physical device.
Association between serum free fatty acid levels and nonalcoholic fatty liver disease: a cross-sectional study
Authors: Zhang Juanwen , Zhao Ying , Xu Chengfu , Hong Yani , Lu Huanle , Wu Jianping , Chen Yu 
Published: July 2014

AbstractHigh serum free fatty acid (FFA) levels are associated with metabolic syndrome (MS). This study aimed to assess the association of fasting serum FFAs with nonalcoholic fatty liver disease (NAFLD) in a Chinese population. A total of 840 subjects fulfilled the diagnostic criteria of NAFLD and 331 healthy control participants were enrolled in this cross-sectional study. Fasting serum FFA levels and other clinical and laboratory parameters were measured. NAFLD patients had significantly higher serum FFA levels than controls (P < 0.001). Serum FFA levels were significantly and positively correlated with parameters of MS, inflammation indexes and markers of hepatocellular damage. Elevated serum FFA levels were found in NAFLD subjects with individual components of MS (obesity, hypertriglyceridaemia and hyperglycaemia). Stepwise regression showed that serum FFA levels were an independent factor predicting advanced fibrosis (FIB-4 ≥ 1.3) in NAFLD patients. Serum FFA levels correlated with NAFLD and could be used as an indicator for predicting advanced fibrosis in NAFLD patients.
Nanosecond Pulsed Electric Fields (nsPEFs) Regulate Phenotypes of Chondrocytes through Wnt/β-catenin Signaling Pathway
Authors: Zhang Kun , Guo Jinsong , Ge Zigang , Zhang Jue 
Published: July 2014

AbstractNanosecond pulsed electric fields (nsPEFs) characterized by high voltage, low energy and non-thermal effects, have been broadly investigated as a potential tumor therapy; however, little is known about their effects on somatic cells. In this current study, we evaluated effects of nsPEFs on the phenotype of chondrocytes (morphology, glycosaminoglycan (GAG) content, proliferation and gene expression) and explored the mechanisms involved. Our results demonstrated that exposing chondrocytes to nsPEFs led to enhanced proliferation and dedifferentiation, evidenced by the upregulated gene expression of collagen type I (COL I) and downregulated gene expression of Sox9, collagen type II (COL II) and aggrecan (AGG) with activation of the wnt/β-catenin signaling pathway. Inhibition of the wnt/β-catenin pathway partially blocked these effects. Thus we concluded that nsPEFs induce dedifferentiation of chondrocytes partially through transient activation of the wnt/β-catenin signaling pathway.
Compact six‐band triplexer using stub‐loaded stepped impedance resonators
Authors: Zhang Ling‐Zhi , Wu Bian , Qiu Feng 
Published: July 2014

A novel six‐band triplexer based on short‐ and open‐ended stub‐loaded stepped impedance resonators (SLSIRs) is presented. The stub added at the centre of the SIR introduces a flexible even mode close to the first odd mode, realising a dual‐band response with nearby passbands and a wide stop band. Three second‐order dual‐band channels combined with a common T‐shaped SIR feed line form a six‐band triplexer with compact size, low insertion loss and high isolation. A practical six‐band triplexer operating at 1.9/2.4, 3.5/4.2 and 5.2/5.8 GHz is designed and realised based on the proposed multi‐band multiplexer coupling scheme.
14–30 GHz low‐power sub‐harmonic single‐balanced gate‐pumped mixer with transformer combiner in 0.18 μm CMOS
Authors: Chiou H.‐K. , Kuo S.‐C. , Chung H.‐Y. 
Published: July 2014

A 14–30 GHz sub‐harmonic single‐balanced gate‐pumped mixer with a wideband transformer combiner in 0.18 μm CMOS technology is presented. The transistors of the sub‐harmonic mixer core are biased at weak inversion to lower the required local oscillator (LO) driving power and DC power consumption. The wideband combiner including a Marchand balun and a 1:1:1 trifilar transformer was designed to combine the radio frequency (RF) and LO driving signals to produce four states of signals, where the RF frequency is about twice the LO frequency. Two quarter‐wavelength transmission lines are adopted to improve the RF‐to‐intermediate‐frequency (IF) and 2LO‐to‐IF isolations. The measured results show that the maximum conversion gain of −1 dB is at 18 GHz and a 3 dB bandwidth is from 14 to 30 GHz while applying the LO driving power of only 1 dBm. The total power consumption including the output buffer is only 7.8 mW.
Full‐duplex MIMO system based on antenna cancellation technique
Authors: Foroozanfard E. , Franek O. , Tatomirescu A. , Tsakalaki E. , de Carvalho E. , Pedersen G.F. 
Published: July 2014

The performance of an antenna cancellation technique for a multiple‐input–multiple‐output (MIMO) full‐duplex system that is based on null‐steering beamforming and antenna polarisation diversity is investigated. A practical implementation of a symmetric antenna topology comprising three dual‐polarised patch antennas operating at 2.4 GHz is described. The measurement results show an average of 60 dB self‐interference cancellation over 200 MHz bandwidth. Moreover, a decoupling level of up to 22 dB is achieved for MIMO multiplexing using antenna polarisation diversity. The performance evaluation of the proposed technique was performed by simulation and measurement and the results have good agreement.
Low onset voltage of GaN on Si Schottky barrier diode using various recess depths
Authors: Park Youngrak , Kim Jung‐Jin , Chang Woojin , Jang Hyun‐Gyu , Na Jeho , Lee Hyunsoo , Jun Chi‐Hoon , Cha Ho‐young , Mun Jae Kyoung , Ko Sang Choon , Nam Eun Soo 
Published: July 2014

A low onset voltage AlGaN/GaN diode with a width of 14 mm is achieved. The recess depth of the AlGaN layer is responsible for the low onset voltage. In comparison with the conventional non‐recessed diode, the onset voltage reduces by 45% along with a decrease of reverse leakage current by about one order of magnitude.
Compact ACS‐fed monopole antenna with rectangular SRRs for tri‐band operation
Authors: Kang Le , Wang Hao , Wang Xin Huai , Shi Xiaowei 
Published: July 2014

A compact uniplanar monopole antenna is presented for tri‐band operation. The antenna is fed by an asymmetric coplanar strip (ACS), which can provide an effective way to reduce the antenna size. Two rectangular split‐ring resonators (SRRs) are etched on the radiating patch to achieve a tri‐band resonant characteristic and good performance of interference suppression. The proposed antenna with a total size of 32 × 12 mm2 has been constructed and tested. The measured results indicate that the designed antenna has 10 dB impedance bandwidths of 340 MHz (2.36–2.70 MHz), 390 MHz (3.35–2.74 GHz) and 1110 MHz (5.01–6.12 GHz), which meet the requirements of the 2.4/5.2/5.8 GHz wireless local area network (WLAN) and 2.5/3.5/5.5 GHz worldwide interoperability for microwave access (WiMAX) applications.
Open platform, 32‐channel, portable, data‐logger with 32 PGA control lines for wearable medical device development
Authors: Gargiulo G.D. , Bifulco P. , Cesarelli M. , McEwan A. , Wabnitz A. 
Published: July 2014

A compact isolated low‐power 32‐channel 16‐bit data‐logging system around an NXP ARM processor (LPC1768) and four of the linear technology octal analogue‐to‐digital converters (ADCs) LTC1857/58/59 is designed. The system requires only 250 mA when powered at 5 V to run at full power (including a capacitive 2.8 inch touch‐screen display and 32 Gb SHDC SD memory card). The sample rate is configurable up to 1 k SPS per channel as well as voltage dynamic input up to ±10 V; additionally, 32 chip select lines (SPI protocol) individually addressable and controllable while sampling to configure user‐designed programmable gain amplifiers (PGAs) are available. Collaboration is being sought to improve the software capabilities, particularly to enrich the very basic user interface and to add wireless connectivity. The code is available (under the GPL licence) at our repository, the gerber file to reproduce the PCB is available (on the As‐Is basis) on request. The galvanic isolation between the power supply data connection and ADC channels makes the data‐logger also compatible with the main powered PCs, hence it is suitable for the implementation of medical devices at least for the prototyping and initial testing stages.
Compact, high gain, hetero‐composite Nd:YVO4/SiC thin disk amplifier with advanced thermal management
Authors: Newburgh G.A. , Dubinskii M. 
Published: July 2014

A thermally advanced, Nd:YVO4 amplifier at 1064 nm based on an 800 µm‐thick Nd:YVO­4 gain layer bonded to a silicon carbide (SiC) prism is demonstrated. The amplifier was tested in the ‘master oscillator–power amplifier’ configuration, where both the seed source and the amplifier were operated in a quasi‐continuous‐wave regime. The hetero‐composite Nd:YVO4/SiC gain element pumped by an 808 nm laser diode bar stack amplified the seed power in a range of 1–55 W with a gain of 4–2.6, respectively. The temperature profile of the gain element measured by a thermal camera indicated the maximum observed temperature excursion at pump saturation intensity to be only 27°C.
Wideband hybrid circularly polarised rectangular dielectric resonator antenna excited by modified cross‐slot
Authors: Zou Meng , Pan Jin 
Published: July 2014

A wideband circularly polarised (CP) rectangular dielectric resonator antenna (DRA) based on the concept of a hybrid antenna is presented. In this design, the modified cross‐slot simultaneously performs the functions of an effective radiator and the feeding structure of the rectangular dielectric resonator (DR). By properly designing the structure parameters of the DRA, the resonances of the modified cross‐slot and the DR can be merged to obtain a wide CP bandwidth. A prototype antenna is designed, fabricated and measured, and a wide 3 dB axial ratio bandwidth of 24.6% is achieved.
Electrical conductivity measurement in Thiel‐embalmed tissue model: relevance to radiofrequency ablation
Authors: Wang Zhigang , Luo Hongyan , Nick M. , Gueorguieva M. , Andre P. , Baker R.T. , McLean D. , Brown S. , Cuschieri A. 
Published: July 2014

Thiel‐embalmed human cadaveric specimens are used widely for biomedical scientific investigation. This Letter reports electrical impedance measurements of Thiel‐embalming solutions from 1 Hz to 32 MHz. Compared with other solutions studied, Thiel solution has the lowest impedance throughout the test spectrum. The electrical conductivity of a Thiel‐embalmed liver sample exhibited a relatively flat frequency response from 100 to 500 kHz, which is the frequency range used for electro‐surgery and radiofrequency tumour ablation (RFA). It measured 5 Sm−1 compared with 0.22 Sm−1 obtained from ex‐vivo fresh pig liver. Using finite element modelling and experimental evaluation, the ablation zone obtained from the Thiel‐embalmed liver sample was extremely small due to its much higher conductivity. Hence, it is concluded that Thiel‐embalmed tissue cannot be used as a reliable model for RFA evaluation.
13.625 Gb/s real‐time dual‐band adaptive optical orthogonal frequency division multiplexing transmissions over 25 km standard single‐mode fibre intensity modulation and direct detection systems utilising strongly saturated reflective semiconductor optical amplifier intensity modulators
Authors: Zhang Qianwu , Hugues‐Salas Emilio , Giddings Roger P. , Zhang Junjie , Wang Min , Tang Jianming 
Published: July 2014

Record‐high 13.625 Gb/s real‐time end‐to‐end dual‐band optical orthogonal frequency division multiplexing (OFDM) transmissions are experimentally demonstrated over intensity modulation and direct detection‐based 25 km standard single‐mode fibres utilising 1.125 GHz reflective semiconductor optical amplifier (RSOA) intensity modulators. The 7.375 Gb/s OFDM baseband (0–2 GHz) and 6.25 Gb/s OFDM passband (4.125–8.125 GHz) are adaptively modulated independently and sampled at 4 GS/s. Experimental results show that strongly saturated RSOAs can intensity‐modulate adaptive bit‐ and power‐loaded radio frequency (RF) OFDM signals having bandwidths approximately eight times higher than the 3 dB small‐signal modulation bandwidths of the RSOAs.
Analysis, design and performance of a zero‐current‐switching pulse‐width‐modulation interleaved boost dc/dc converter
Authors: Wang Chien‐Ming , Lin Chang‐Hua , Hsu Shih‐Yung , Lu Chien‐Min , Li Jyun‐Che 
Published: July 2014

A novel interleaved boost dc/dc converter with zero‐current‐switching pulse‐width‐modulation (ZCS‐PWM) characteristic using a simple ZCS‐PWM auxiliary circuit is presented in this paper. The proposed converter combines the conventional PWM technique and ZCS technique to promote the circuit performance. The proposed converter uses dual boost converters which are operated at interleaved mode to increase the output power level. Thus, the proposed converter does not only decreases the current stress on main circuit devices but reduces the input ripple current and output capacitor size. Because the proposed converter establishes a common ZCS‐PWM auxiliary circuit on used dual boost converters, it can greatly reduce the size and cost. And, it can provide the ZCS characteristic on main switches and auxiliary switches with a wide range of load to improve the problem of switching losses and EMI. Thus, its topology is simple and compact. Besides operating at constant frequency and reducing commutation losses, the proposed converter has no additional current stress and conduction loss in the main switch compared with the conventional interleaved boost dc/dc converter. The principle of operation, theoretical analysis and experimental results of the proposed boost converter, rated 1 kW and operating at 40 kHz, are provided in this paper to verify the performance of this new family of converters.