bluuebunny/crossref_metadata_2025 huggingface dataset:
Harmonic influence of traction locomotive on hybrid DC asynchronous interconnection project
Authors: Shuying Guo , Minxiao Han , Ruoxi Liu , Jun Wen
Published: December 2017

Traction locomotive is one of the harmonic sources in power system. This study firstly analyses the principle of harmonic generation in traction locomotive, then the equivalent harmonic current source model of traction power supply system is built on the power supply bus side of traction substation. On this basis, a mathematical model is established to analyse the propagation characteristics of the harmonics generated by the traction system among different voltage levels. A harmonic transfer simulation model in PSASP was built with the actual parameters of Luxi hybrid DC asynchronous interconnection project. Using this model, the research on the influence of the traction locomotive harmonics on Luxi DC project and the AC grid connected to the project is carried out. The simulation results provide an effective guidance for reducing the adverse impact of harmonics on the hybrid DC asynchronous interconnection system and ensuring the safe operation of the project.
Radio and infrared study of southern H II regions
G346.056−0.021
and G346.077−0.056
Authors: Das S. R. , Tej A. , Vig S. , Liu T. , Ghosh S. K. , Chandra C. H. I.
Published: December 2017

Aim. We present a multiwavelength study of two southern Galactic H II regions G346.056−0.021 and G346.077−0.056 which are located at a distance of 10.9 kpc. The distribution of ionized gas, cold and warm dust, and the stellar population associated with the two H II regions are studied in detail using measurements at near-infrared, mid-infrared, far-infrared, submillimeter and radio wavelengths.

Methods. The radio continuum maps at 1280 and 610 MHz were obtained using the Giant Metrewave Radio Telescope to probe the ionized gas. The dust temperature, column density, and dust emissivity maps were generated using modified blackbody fits in the far-infrared wavelength range 160–500 μm. Various near- and mid-infrared color and magnitude criteria were adopted to identify candidate ionizing star(s) and the population of young stellar objects in the associated field.

Results. The radio maps reveal the presence of diffuse ionized emission displaying distinct cometary morphologies. The 1280 MHz flux densities translate to zero age main sequence spectral types in the range O7.5V–O7V and O8.5V–O8V for the ionizing stars of G346.056−0.021 and G346.077−0.056, respectively. A few promising candidate ionizing star(s) are identified using near-infrared photometric data. The column density map shows the presence of a large, dense dust clump enveloping G346.077−0.056. The dust temperature map shows peaks towards the two H II regions. The submillimeter image shows the presence of two additional clumps, one being associated with G346.056−0.021. The masses of the clumps are estimated to range between ~1400 and 15250 M⊙. Based on simple analytic calculations and the correlation seen between the ionized gas distribution and the local density structure, the observed cometary morphology in the radio maps is better explained invoking the champagne-flow model.
Dust cloud evolution in sub-stellar atmospheres via plasma deposition and plasma sputtering
Authors: Stark C. R. , Diver D. A.
Published: December 2017

Context.In contemporary sub-stellar model atmospheres, dust growth occurs through neutral gas-phase surface chemistry. Recently, there has been a growing body of theoretical and observational evidence suggesting that ionisation processes can also occur. As a result, atmospheres are populated by regions composed of plasma, gas and dust, and the consequent influence of plasma processes on dust evolution is enhanced.

Aim.This paper aims to introduce a new model of dust growth and destruction in sub-stellar atmospheres via plasma deposition and plasma sputtering.

Methods.Using example sub-stellar atmospheres fromDRIFT-PHOENIX, we have compared plasma deposition and sputtering timescales to those from neutral gas-phase surface chemistry to ascertain their regimes of influence. We calculated the plasma sputtering yield and discuss the circumstances where plasma sputtering dominates over deposition.

Results.Within the highest dust density cloud regions, plasma deposition and sputtering dominates over neutral gas-phase surface chemistry if the degree of ionisation is ≳10−4. Loosely bound grains with surface binding energies of the order of 0.1–1 eV are susceptible to destruction through plasma sputtering for feasible degrees of ionisation and electron temperatures; whereas, strong crystalline grains with binding energies of the order 10 eV are resistant to sputtering.

Conclusions.The mathematical framework outlined sets the foundation for the inclusion of plasma deposition and plasma sputtering in global dust cloud formation models of sub-stellar atmospheres.
Two-dimensional modeling of density and thermal structure of dense circumstellar outflowing disks
Authors: Kurfürst P. , Feldmeier A. , Krtička J.
Published: December 2017

Context. Evolution of massive stars is affected by a significant loss of mass either via (nearly) spherically symmetric stellar winds or by aspherical mass-loss mechanisms, namely the outflowing equatorial disks. However, the scenario that leads to the formation of a disk or rings of gas and dust around massive stars is still under debate. It is also unclear how various forming physical mechanisms of the circumstellar environment affect its shape and density, as well as its kinematic and thermal structure.

Aims. We study the hydrodynamic and thermal structure of optically thick, dense parts of outflowing circumstellar disks that may be formed around various types of critically rotating massive stars, for example, Be stars, B[e] supergiant (sgB[e]) stars or Pop III stars. We calculate self-consistent time-dependent models of temperature and density structure in the disk’s inner dense region that is strongly affected by irradiation from a rotationally oblate central star and by viscous heating.

Methods. Using the method of short characteristics, we specify the optical depth of the disk along the line-of-sight from stellar poles. Within the optically thick dense region with an optical depth of τ > 2∕3 we calculate the vertical disk thermal structure using the diffusion approximation while for the optically thin outer layers we assume a local thermodynamic equilibrium with the impinging stellar irradiation. For time-dependent hydrodynamic modeling, we use two of our own types of hydrodynamic codes: two-dimensional operator-split numerical code based on an explicit Eulerian finite volume scheme on a staggered grid, and unsplit code based on the Roe’s method, both including full second-order Navier-Stokes shear viscosity.

Results. Our models show the geometric distribution and contribution of viscous heating that begins to dominate in the central part of the disk for mass-loss rates higher than Ṁ ≳ 10−10 M⊙ yr−1. In the models of dense viscous disks with Ṁ > 10−8 M⊙ yr−1, the viscosity increases the central temperature up to several tens of thousands of Kelvins, however the temperature rapidly drops with radius and with distance from the disk midplane. The high mass-loss rates and high viscosity lead to instabilities with significant waves or bumps in density and temperature in the very inner disk region.

Conclusions. The two-dimensional radial-vertical models of dense outflowing disks including the full Navier-Stokes viscosity terms show very high temperatures that are however limited to only the central disk cores inside the optically thick area, while near the edge of the optically thick region the temperature may be low enough for the existence of neutral hydrogen, for example.
Detection of new eruptions in the Magellanic Clouds luminous blue variables R 40 and R 110
Authors: Campagnolo J. C. N. , Borges Fernandes M. , Drake N. A. , Kraus M. , Guerrero C. A. , Pereira C. B.
Published: December 2017

We performed a spectroscopic and photometric analysis to study new eruptions in two luminous blue variables (LBVs) in the Magellanic Clouds. We detected a strong new eruption in the LBV R40 that reachedV~ 9.2 in 2016, which is around 1.3 mag brighter than the minimum registered in 1985. During this new eruption, the star changed from an A-type to a late F-type spectrum. Based on photometric and spectroscopic empirical calibrations and synthetic spectral modeling, we determine that R 40 reachedTeff= 5800–6300 K during this new eruption. This object is thereby probably one of the coolest identified LBVs. We could also identify an enrichment of nitrogen andr- ands-process elements. We detected a weak eruption in the LBV R 110 with a maximum ofV~ 9.9 mag in 2011, that is, around 1.0 mag brighter than in the quiescent phase. On the other hand, this new eruption is about 0.2 mag fainter than the first eruption detected in 1990, but the temperature did not decrease below 8500 K.Spitzerspectra show indications of cool dust in the circumstellar environment of both stars, but no hot or warm dust was present, except by the probable presence of PAHs in R 110. We also discuss a possible post-red supergiant nature for both stars.
Infrared spectra of complex organic molecules in astronomically relevant ice matrices
Authors: Terwisscha van Scheltinga J. , Ligterink N. F. W. , Boogert A. C. A. , van Dishoeck E. F. , Linnartz H.
Published: December 2017

Context. The number of identified complex organic molecules (COMs) in inter- and circumstellar gas-phase environments is steadily increasing. Recent laboratory studies show that many such species form on icy dust grains. At present only smaller molecular species have been directly identified in space in the solid state. Accurate spectroscopic laboratory data of frozen COMs, embedded in ice matrices containing ingredients related to their formation scheme, are still largely lacking.

Aim. This work provides infrared reference spectra of acetaldehyde (CH3CHO), ethanol (CH3CH2OH), and dimethyl ether (CH3OCH3) recorded in a variety of ice environments and for astronomically relevant temperatures, as needed to guide or interpret astronomical observations, specifically for upcoming James Webb Space Telescope observations.

Methods. Fourier transform transmission spectroscopy (500–4000 cm−1/20–2.5 μm, 1.0 cm−1 resolution) was used to investigate solid acetaldehyde, ethanol and dimethyl ether, pure or mixed with water, CO, methanol, or CO:methanol. These species were deposited on a cryogenically cooled infrared transmissive window at 15 K. A heating ramp was applied, during which IR spectra were recorded until all ice constituents were thermally desorbed.

Results. We present a large number of reference spectra that can be compared with astronomical data. Accurate band positions and band widths are provided for the studied ice mixtures and temperatures. Special efforts have been put into those bands of each molecule that are best suited for identification. For acetaldehyde the 7.427 and 5.803 μm bands are recommended, for ethanol the 11.36 and 7.240 μm bands are good candidates, and for dimethyl ether bands at 9.141 and 8.011 μm can be used. All spectra are publicly available in the Leiden Database for Ice.
Validity of abundances derived from spaxel spectra of the MaNGA survey
Authors: Pilyugin L. S. , Grebel E. K. , Zinchenko I. A. , Nefedyev Y. A. , Shulga V. M. , Wei H. , Berczik P.P.
Published: December 2017

We measured the emission lines in the spaxel spectra of Mapping Nearby Galaxies at Apache Point Observatory (MaNGA) galaxies in order to determine the abundance distributions therein. It has been suggested that the strength of the low-ionization lines, R2, N2, and S2, may be increased (relative to Balmer lines) in (some) spaxel spectra of the MaNGA survey due to a contribution of the radiation of the diffuse ionized gas. Consequently, the abundances derived from the spaxel spectra through strong-line methods may suffer from large errors. We examined this expectation by comparing the behaviour of the line intensities and the abundances estimated through different calibrations for slit spectra of H II regions in nearby galaxies, for fibre spectra from the Sloan Digital Sky Survey, and for spaxel spectra of the MaNGA survey. We found that the S2 strength is increased significantly in the fibre and spaxel spectra. The mean enhancement changes with metallicity and can be as large as a factor of ~2. The mean distortion of R2 and N2 is less than a factor of ~1.3. This suggests that Kaufmann et al.’s (2003, MNRAS, 346, 1055) demarcation line between active galactic nuclei and H II regions in the Baldwin, Phillips, & Terlevich (BPT, 1981, PASP, 93, 5) diagram is a useful criterion to reject spectra with significantly distorted strengths of the N2 and R2 lines. We find that the three-dimensional R calibration, which uses the N2 and R2 lines, produces reliable abundances in the MaNGA galaxies. The one-dimensional N2 calibration produces either reliable or wrong abundances depending on whether excitation and N/O abundance ratio in the target region (spaxel) are close to or differ from those parameters in the calibrating points located close to the calibration relation. We then determined abundance distributions within the optical radii in the discs of 47 MaNGA galaxies. The optical radii of the galaxies were estimated from the surface brightness profiles constructed based on the MaNGA observations.
Dynamiques d'intégration des espaces naturels protégés en France : une approche comparative entre parcs nationaux et réserves naturelles
Authors: Cosson Arnaud , Therville Clara , Mathevet Raphaël , Arpin Isabelle , Bioret Frédéric
Published: December 2017

Ces trente dernières années, les espaces naturels protégés (ENP) ont connu un changement majeur de paradigme, des approches ségrégatives aux approches intégratives. Les cadres d'analyse traitant de la transformation des systèmes socioécologiques et des biens communs permettent de comparer ce processus de transformation entre deux grands types d'ENP en France : les parcs nationaux et les réserves naturelles. Tandis que les trajectoires d'intégration des parcs s'expliquent par une injonction descendante, celles de certaines réserves sont issues de processus ascendants. Si la comparaison entre parcs et réserves révèle des variables clés dans la mise en œuvre des approches intégratives (leadership, capital social, articulation entre niveaux de règle), leur articulation diffère du fait de l'histoire de ces outils, de l'origine du processus de transformation et d'effets d'échelle.
A note on reliability analysis of an N-policy unreliable MX / (G1G2) /1 queue with optional repeated service
Authors: Kalita Chandi Ram , Choudhury Gautam
Published: December 2017

This article deals with analyse the system reliability function of an unreliable MX / (G1G2) /1queue with optional repeated service under N policy, where server turned on the system when batches of N(≥ 1) units accumulated in the queue.
Advances in Imaging Multiple Sclerosis
Authors: Caverzasi Eduardo , Cordano Christian , Hauser Stephen , Henry Roland , Bischof Antje
Published: December 2017

Neuroimaging has emerged as a powerful technology that has enabled visualization of the impact of multiple sclerosis (MS) on the central nervous system in vivo with unprecedented precision. It has played a crucial role in disentangling the chronology of inflammation and neurodegeneration, developing and understanding mechanisms of novel therapeutics, and diagnosing and monitoring the disease in the clinical setting. However, challenges pertaining to the limited resolution, lack of specificity, inherent technological biases, and processing of increasingly big datasets have hindered comprehensive insights into the pathology underlying disability.

Here, we review the advances in neuroimaging for MS that have moved the field forward in recent years by addressing the above-mentioned issues, thereby enhancing our knowledge of this yet enigmatic disease. We discuss complementary imaging technologies, including magnetic resonance imaging, positron emission tomography, and optical coherence tomography, the most recent tool in the MS imaging armamentarium that holds promise to act as a surrogate of pathological changes in the central nervous system in a more easily accessible way.
Functional Networks in Disorders of Consciousness
Authors: Chatelle Camille , Edlow Brian , Bodien Yelena
Published: December 2017

Severe brain injury may cause disruption of neural networks that sustain arousal and awareness, the two essential components of consciousness. Despite the potentially devastating immediate and long-term consequences, disorders of consciousness (DoC) are poorly understood in terms of their underlying neurobiology, the relationship between pathophysiology and recovery, and the predictors of treatment efficacy. Recent advances in neuroimaging techniques have enabled the study of network connectivity, providing great potential to improve the clinical care of patients with DoC. Initial discoveries in this field were made using positron emission tomography (PET). More recently, functional magnetic resonance (fMRI) techniques have added to our understanding of functional network dynamics in this population. Both methods have shown that whether at rest or performing a goal-oriented task, functional networks essential for processing intrinsic thoughts and extrinsic stimuli are disrupted in patients with DoC compared with healthy subjects. Atypical connectivity has been well established in the default mode network as well as in other cortical and subcortical networks that may be required for consciousness. Moreover, the degree of altered connectivity may be related to the severity of impaired consciousness, and recovery of consciousness has been shown to be associated with restoration of connectivity. In this review, we discuss PET and fMRI studies of functional and effective connectivity in patients with DoC and suggest how this field can move toward clinical application of functional network mapping in the future.
Clinical Experience with the Implementation of Accurate Measurement of Blood Loss during Cesarean Delivery: Influences on Hemorrhage Recognition and Allogeneic Transfusion
Authors: Zamudio Stacy , Al-Khan Abdulla , Douglas Claudia , Sledge Sharon , Tully Griffeth , Thurer Robert , Rubenstein Andrew
Published: December 2017

Objective This article compares hemorrhage recognition and transfusion using accurate, contemporaneous blood loss measurement versus visual estimation during cesarean deliveries.

Study Design A retrospective cohort study using visually estimated blood loss (traditional, n = 2,025) versus estimates using a mobile application that photographs sponges and canisters and calculates their hemoglobin content (device, n = 756).

Results Blood loss > 1,000 mL was recognized in 1.9% of traditional visual estimation patients, while measured blood loss of > 1,000 mL occurred in 8.2% of device patients (p < 0.0001). In both groups, this was accompanied by a greater decrease in transfusion-adjusted hemoglobin levels than occurred in patients without hemorrhage (p < 0.0001). Despite similar transfusion rates (1.6% in both groups), fewer red cell units were given to transfused patients in the device group (1.83 ± 0.58 versus 2.56 ± 1.68 units; p = 0.038). None of the patients in the device group received plasma or cryoprecipitate. Seven patients in the traditional group received these products (p = 0.088). Device use was associated with shorter hospital stays (4.0 ± 2.3 versus 4.4 ± 2.9 days; p = 0.0006).

Conclusion The device identified hemorrhages more frequently than visual estimation. Device-detected hemorrhages appeared clinically relevant. Blood product transfusion was reduced possibly due to earlier recognition and treatment, although further studies are needed to verify the conclusion.
Management des Lymphödems
Authors: Baumeister Rüdiger
Published: December 2017

Was ist neu?

Aktueller Stand Gerade ist die S2k-Leitlinie „Diagnostik und Therapie der Lymphödeme“ bei der AWMF akkreditiert worden (AWMF Reg.-Nr. 058 – 001). Auf diese Leitlinie wird in dem Artikel besonders Bezug genommen und Angaben daraus verwendet 1.

Diagnostik des Lymphödems Mögliche Störungen des Lymphtransportes sollen frühzeitig beachtet und zunächst basisdiagnostisch durch lymphbezogene Anamnese, Inspektion und Palpation erkannt werden. Insbesondere durch die Lymphszintigrafie lässt sich – falls nötig – eine genauere Quantifizierung des Lymphabstroms bestimmen.

Konservative Therapie Alle Elemente der komplexen physikalischen Entstauungstherapie (KPE) sollten als Basis der Behandlung eines Lymphödems zum Einsatz kommen. Dies sind: Hautpflege, manuelle Lymphdrainage, Kompressionstherapie und/oder lymphologische Kompressionsstrumpfversorgung, entstauungsfördernde Sport-/Bewegungstherapie sowie eine Aufklärung und Schulung zur individuellen Selbsttherapie.

Chirurgische Therapie Operative Maßnahmen, vor allem solche, die eine Verbesserung des Lymphabtransportes bewirken, sind bei Leidensdruck der Patienten und einer Zunahme sekundäre Gewebeveränderungen indiziert.
Substanzabhängigkeit im Alter
Authors: Pantel Johannes
Published: December 2017

Was ist neu?

Substanzabhängigkeit steigt im Alter überproportional an Der missbräuchliche oder abhängige Konsum von Substanzen durch ältere Menschen wird in Zukunft nicht nur in absoluten Zahlen, sondern vermutlich auch überproportional ansteigen. Dies erfordert eine bessere einschlägige Qualifikation der beteiligten Berufsgruppen (Ärzte, Pflegekräfte usw.), aber auch einen Ausbau der heute bereits unzureichenden Versorgungsstrukturen.

Alkoholmissbrauch und -abhängigkeit Ältere Menschen unterliegen einer Vielzahl psychosozialer Risikofaktoren für die Entwicklung einer manifesten Alkoholabhängigkeit bei gleichzeitig erhöhter Vulnerabilität für alkoholassoziierte Folgeschäden. Die Behandlungsprognose ist jedoch bei gegebener Therapiemotivation gut und teilweise besser als bei jüngeren Patienten. Dies gilt vor allem, wenn sich die Abhängigkeit erst im höheren Lebensalter entwickelt hat („Late-Onset“-Alkoholismus).

Benzodiazepine und andere Hypnotika Gerade unter hochbetagten Menschen und Heimbewohnern wird eine Dauerbehandlung mit Benzodiazepinen und Benzodiazepin-Analoga („Z-Drugs“) immer noch erschreckend häufig durchgeführt und dabei das hohe Risiko einer Abhängigkeitsentwicklung in Kauf genommen. Neuere Befunde deuten darauf hin, dass dadurch auch die Entwicklung einer Demenz begünstigt werden kann. Eine Langzeitbehandlung sollte daher zugunsten präventiver Ansätze vermieden werden.

Opiate Zuverlässige Zahlen über die Häufigkeit von Abhängigkeitsentwicklungen bei älteren, nicht onkologischen Patienten, die unter einer Dauerbehandlung mit Opioidanalgetika stehen, liegen für Deutschland bislang nicht vor. Angesichts neuerer Erkenntnisse sollte das Risiko einer komplexen persistierenden Abhängigkeit gleichwohl nicht vernachlässigt und die Indikation sehr sorgfältig gestellt werden.
Aus der Geschichte der Deutschen Gesellschaft für Innere Medizin (DGIM)
Authors: Forsbach Ralf , Hofer Hans-Georg
Published: December 2017

51 years after its founding in 1882, the "Congress for Internal Medicine", 1920 renamed "German Society for Internal Medicine (DGIM)", fell into heavy water. While during the Kaiserreich and the Weimar Republic the medical care for the individual patient had never been seriously questioned, the proclaimed “Third Reich” brought fundamental changes. The 1164 male and 13 female physicians, who had been organized in the DGIM 1933, had to position themselves in the Nazi dictatorship. The same applied for the society as a whole.

The behavior of the German Society of Internal Medicine during the Nazi period is disenchanting. The society completely subordinated to the Nazi regime. The scientific program of the meetings was oriented to the ideological interests of the regime. Solidarity with nazi-persecuted people is only apparent in rare cases. On the contrary, even DGIM chairmen were involved in expulsions and NS-medical crimes. Cautious criticism was limited to a few areas, such as the “Neue Deutsche Heilkunde” (“New German Healing”) and the study conditions at the universities. Only individual DGIM members developed oppositional behavior on the basis of personal conviction.

In accordance with the more recent research on the Nazi era, these results both clarify and broaden the picture of scientific organizations in general and medical societies in particular.
Constituents of Acacia nilotica (L.) Delile with Novel Kinase Inhibitory Activity
Authors: Ahmadu Augustine , Agunu Abdulkarim , Nguyen Thi-Ngoc-Dung , Baratte Blandine , Foll-Josselin Béatrice , Ruchaud Sandrine , Serive Benoît , Bach Stéphane
Published: December 2017

Acacia nilotica (L.) Delile belongs to the genus Acacia, which includes about 1400 species in subtropical and tropical Africa including Nigeria, Senegal, Egypt, and Mozambique as well as Asia from India to Burma. This plant is traditionally used to treat several pathologies such as mouth, ear, and bone cancer. Moreover, it possesses many other biological activities (antidiarrheal, anti-inflammatory, antimicrobial, and antifungal). We report here the extraction, purification, and identification of two known compounds [ethylgallate and (+)-catechin] from the bark of the tree that were further tested for their inhibitory activities against a panel of disease-related protein kinases. Both compounds were active, and (+)-catechin showed the best activity by inhibiting nine out of fourteen protein kinases with an IC50 value in the µg/mL range. This compound gave the highest activity against CLK1 with an IC50 of 2.1 µg/mL. The ethyl acetate extract and its components, such as catechins and other polyphenols, which also had protein kinase inhibitory activity, can be exploited in the research for anticancer agents.
An efficient multi-dimensional implementation of VSIAM3 and its applications to free surface flows
Authors: Yokoi Kensuke , Furuichi Mikito , Sakai Mikio
Published: December 2017

We propose an efficient multidimensional implementation of VSIAM3 (volume/surface integrated average-based multi-moment method). Although VSIAM3 is a highly capable fluid solver based on a multi-moment concept and has been used for a wide variety of fluid problems, VSIAM3 could not simulate some simple benchmark problems well (for instance, lid-driven cavity flows) due to relatively high numerical viscosity. In this paper, we resolve the issue by using the efficient multidimensional approach. The proposed VSIAM3 is shown to capture lid-driven cavity flows of the Reynolds number up to Re = 7500 with a Cartesian grid of 128 × 128, which was not capable for the original VSIAM3. We also tested the proposed framework in free surface flow problems (droplet collision and separation of We = 40 and droplet splashing on a superhydrophobic substrate). The numerical results by the proposed VSIAM3 showed reasonable agreements with these experiments. The proposed VSIAM3 could capture droplet collision and separation of We = 40 with a low numerical resolution (8 meshes for the initial diameter of droplets). We also simulated free surface flows including particles toward non-Newtonian flow applications. These numerical results have showed that the proposed VSIAM3 can robustly simulate interactions among air, particles (solid), and liquid.
An improved sliding mode controller for a multifunctional photovoltaic grid tied inverter
Authors: Safa Ahmed , Berkouk El Madjid , Messlem Youcef , Gouichiche Abdelmadjid
Published: December 2017

This paper proposes a robust control algorithm for a photovoltaic (PV) multifunctional grid tied inverter (MFGTI). The MFGTI is used to simultaneously inject the active power of a PV panel and enhance the power quality of a microgrid. The proposed algorithm will estimate the positive fundamental component of the source current even under strongly disturbed main voltage and load conditions. First, a Sliding Mode Controller is used to estimate the magnitude of the source current. Then, a positive fundamental component estimator is used to estimate the unity vector of the main voltage. By multiplying the output of the two blocks, we obtain a pure sinusoidal source current in phase with the main voltage. Using this algorithm, the MFGTI will inject the active power, compensate the reactive power, and enhance the power quality of the microgrid. Thus, the main grid will only supply some amount of active power with a unity power factor. The proposed algorithm is compared with the conventional method to verify its effectiveness. Several loads and main voltage scenarios are simulated and then experimentally tested. The results prove the superiority and effectiveness of the proposed algorithm.
Design and construction of high-frequency magnetic probe system on the HL-2A tokamak
Authors: Liang S. Y. , Ji X. Q. , Sun T. F. , Xu Yuan , Lu J. , Yuan B. S. , Ren L. L. , Yang Q. W.
Published: December 2017

A high-frequency magnetic probe system is designed, calibrated and constructed on the HL-2A tokamak. To investigate the factors which affect the probe frequency response, the inductance and capacitance in the probe system are analyzed using an equivalent circuit. Suitable sizes and turn number of the coil, and the length of transmission cable are optimized based on the theory and detailed test in the calibration. To deal with the frequency response limitation and bake-out, the ceramic grooved technique is used and the probe is wound with a bare copper wire. A cascade filter is manufactured with a suitable bandwidth as well as a good phase consistency between channels. The system has been used in the experiment to measure high frequency (≤300 kHz) magnetohydrodynamic fluctuations, which can meet the requirement of physical analysis on HL-2A.
An efficient hybrid method for stochastic reaction-diffusion biochemical systems with delay
Authors: Sayyidmousavi Alireza , Ilie Silvana
Published: December 2017

Many chemical reactions, such as gene transcription and translation in living cells, need a certain time to finish once they are initiated. Simulating stochastic models of reaction-diffusion systems with delay can be computationally expensive. In the present paper, a novel hybrid algorithm is proposed to accelerate the stochastic simulation of delayed reaction-diffusion systems. The delayed reactions may be of consuming or non-consuming delay type. The algorithm is designed for moderately stiff systems in which the events can be partitioned into slow and fast subsets according to their propensities. The proposed algorithm is applied to three benchmark problems and the results are compared with those of the delayed Inhomogeneous Stochastic Simulation Algorithm. The numerical results show that the new hybrid algorithm achieves considerable speed-up in the run time and very good accuracy.
Charge carrier velocity in graphene field-effect transistors
Authors: Bonmann Marlene , Vorobiev Andrei , Andersson Michael A. , Stake Jan
Published: December 2017

To extend the frequency range of transistors into the terahertz domain, new transistor technologies, materials, and device concepts must be continuously developed. The quality of the interface between the involved materials is a highly critical factor. The presence of impurities can degrade device performance and reliability. In this paper, we present a method that allows the study of the charge carrier velocity in a field-effect transistor vs impurity levels. The charge carrier velocity is found using high-frequency scattering parameter measurements followed by delay time analysis. The limiting factors of the saturation velocity and the effect of impurities are then analysed by applying analytical models of the field-dependent and phonon-limited carrier velocity. As an example, this method is applied to a top-gated graphene field-effect transistor (GFET). We find that the extracted saturation velocity is ca. 1.4×107 cm/s and is mainly limited by silicon oxide substrate phonons. Within the considered range of residual charge carrier concentrations, charged impurities do not limit the saturation velocity directly by the phonon mechanism. Instead, the impurities act as traps that emit charge carriers at high fields, preventing the current from saturation and thus limiting power gain of the GFETs. The method described in this work helps to better understand the influence of impurities and clarifies methods of further transistor development. High quality interfaces are required to achieve current saturation via velocity saturation in GFETs.
Thickness dependence of unidirectional spin-Hall magnetoresistance in metallic bilayers
Authors: Yin Yuxiang , Han Dong-Soo , de Jong Mark C. H. , Lavrijsen Reinoud , Duine Rembert A. , Swagten Henk J. M. , Koopmans Bert
Published: December 2017

A nonlinear magnetoresistance—called unidirectional spin-Hall magnetoresistance—is recently experimentally discovered in metallic bilayers consisting of a heavy metal and a ferromagnetic metal. To study the fundamental mechanism of unidirectional spin-Hall magnetoresistance (USMR), both ferromagnetic and heavy metallic layer thickness dependence of the USMR are presented in a Pt/Co/AlOx trilayer at room temperature. To avoid ambiguities, second harmonic Hall measurements are used for separating spin-Hall and thermal contributions to the non-linear magnetoresistance. The experimental results are fitted by using a drift-diffusion theory, with parameters extracted from an analysis of longitudinal resistivity of the Co layer within the framework of the Fuchs-Sondheimer model. A good agreement with the theory is found, demonstrating that the USMR is governed by both the spin-Hall effect in the heavy metallic layer and the metallic diffusion process in the ferromagnetic layer.
The gas phase structure of α-pinene, a main biogenic volatile organic compound
Authors: Neeman Elias M. , Avilés Moreno Juan Ramón , Huet Thérèse R.
Published: December 2017

The gas phase structure of the bicyclic atmospheric aerosol precursor α-pinene was investigated employing a combination of quantum chemical calculation and Fourier transform microwave spectroscopy coupled to a supersonic jet expansion. The very weak rotational spectra of the parent species and all singly substituted 13C in natural abundance have been identified, from 2 to 20 GHz, and fitted to Watson’s Hamiltonian model. The rotational constants were used together with geometrical parameters from density functional theory and ab initio calculations to determine the rs, r0, and rm(1) structures of the skeleton, without any structural assumption in the fit concerning the heavy atoms. The double C=C bond was found to belong to a quasiplanar skeleton structure containing 6 carbon atoms. Comparison with solid phase structure is reported. The significant differences of α-pinene in gas phase and other gas phase bicyclic monoterpene structures (β-pinene, nopinone, myrtenal, and bicyclo[3.1.1]heptane) are discussed.
Effect of CoFeB electrode compositions on low frequency magnetic noise in tunneling magnetoresistance sensors
Authors: Wisniowski P. , Dabek M. , Wrona J. , Cardoso S. , Freitas P. P.
Published: December 2017

We study the effect of CoFeB electrode compositions on frequency dependent magnetic noise in tunneling magnetoresistance sensors with variable field sensitivity. We use the relationship between the normalized 1/f noise parameter (αt) and the magnetoresistance sensitivity product (MSP) to compare the magnetic noise of sensors with Co40Fe40B20, Co60Fe20B20, and Co20Fe60B20 electrodes. We observed the lowest slope of the αt vs. MSP curve of 9.1 × 10−13 μm3 T and a 1/f noise corner as low as 300 Hz for the sensors with Co60Fe20B20 electrodes. Furthermore, all sensors at a specific value of the magnetoresistance sensitivity product showed a deviation from the linear relationship between αt and MSP. The results show that in the design of high sensitivity CoFeB-MgO-CoFeB based tunneling magnetoresistance sensors for low field detection, selection of CoFeB electrodes is important and can be used to significantly improve the low frequency field detection limit.
Propagational characteristics in a warm hybrid plasmonic waveguide
Authors: Mahmodi Moghadam M. , Shahmansouri M. , Farokhi B.
Published: December 2017

We theoretically analyze the properties of guided modes in a warm planar conductor–gap–dielectric (CGD) system. The latter consists of a high index dielectric, separated from a warm metallic plasma with a low index nano-sized dielectric layer (gap) by using the hydrodynamic model coupled to Maxwell's equations. The effects of thermal pressure on the confinement and the propagation losses of Hybrid Plasmon Polariton (HPP) modes are studied. We found that the thermal effect leads to a reduction in the effective refractive index as well as in the propagation losses of the HPP mode. Furthermore, the cutoff thickness in the warm CGD waveguide is found to be smaller than that in a cold CGD waveguide. The results may be useful in understanding the essential physics of active/passive Plasmonic devices and chip-scale systems.
Fabrication and characterization of a germanium nanowire light emitting diode
Authors: Greil Johannes , Bertagnolli Emmerich , Salem Bassem , Baron Thierry , Gentile Pascal , Lugstein Alois
Published: December 2017

In this letter, we demonstrate the feasibility of a germanium nanowire light emitting diode as a reasonable approach for downscaling of CMOS compatible light sources. We show room-temperature direct bandgap electroluminescence from axial p-n junction nanowire devices. The electron population in the Γ valley, necessary for direct bandgap emission, is achieved by high injection current densities. Carrier temperature is consistently found to be higher than the lattice temperature, indicating inhibited carrier cooling in small diameter wires. Strong polarization of the emission parallel to the nanowire axis is observed and attributed to dielectric contrast phenomena.
Influence of magnet eddy current on magnetization characteristics of variable flux memory machine
Authors: Yang Hui , Lin Heyun , Zhu Z. Q. , Lyu Shukang
Published: December 2017

In this paper, the magnet eddy current characteristics of a newly developed variable flux memory machine (VFMM) is investigated. Firstly, the machine structure, non-linear hysteresis characteristics and eddy current modeling of low coercive force magnet are described, respectively. Besides, the PM eddy current behaviors when applying the demagnetizing current pulses are unveiled and investigated. The mismatch of the required demagnetization currents between the cases with or without considering the magnet eddy current is identified. In addition, the influences of the magnet eddy current on the demagnetization effect of VFMM are analyzed. Finally, a prototype is manufactured and tested to verify the theoretical analyses.
Spectrum for the nonlinear interaction between finite frequency pump inertial Alfvén wave and slow magnetosonic wave in low beta plasmas
Authors: Modi K. V. , Sharma R. P.
Published: December 2017

Nonlinear interplay between the finite frequency inertial Alfvén wave and slow magnetosonic wave for low β-plasma (β≪me/mi) has been studied in the paper. The governing equation of slow magnetosonic wave has been derived in the presence of ponderomotive force associated with the finite frequency inertial Alfvén wave. A numerical simulation has been performed for the set of dimensionless governing equations representing finite frequency inertial Alfvén wave and slow magnetosonic wave for the parameters of auroral region. The localized structures and turbulence spectrum have been studied for the different angles of propagation (like θ=5°,25°,45°,75°) of slow magnetosonic wave. From the results, it has been observed that the localization becomes labyrinthine and varies with the change in the angle of propagation for the slow magnetosonic wave. Further, the spectral index follows the (∼k−3.8) for θ=5°, (∼k−4.05) for θ=25°, (∼k−4.2) for θ=45°, and (∼k−4.35) for θ=75°. Hence, one can conclude that the variation in the angle of propagation of slow magnetosonic wave affects the localization and spectral scaling. This variation may be responsible for the heating and acceleration of the plasma species in auroral region. The relevancy of the simulation results have been shown with the observation recorded by the spacecrafts such as FAST, Heos 2, Hawkeye 1, and Dynamics Explorer 1.
Historical perspectives on the mangroves of Kakadu National Park
Authors: Lucas Richard , Finlayson C. Max , Bartolo Renee , Rogers Kerrylee , Mitchell Anthea , Woodroffe Colin D. , Asbridge Emma , Ens Emilie
Published: December 2017

Mangroves are a major ecosystem within Kakadu National Park in Australia’s Northern Territory, providing coastal protection, high biodiversity and an important resource for Aboriginal people. In the late Holocene (from c. 6000 before present), mangroves occupied much of the estuarine and coastal plains, but their range has subsequently contracted to the main river systems (the West Alligator, South Alligator and East Alligator Rivers, and the Wildman River), tributary creeks and offshore islands (Field and Barrow Islands). On the basis of maps of mangrove extent generated from aerial photography (1950, 1975, 1984 and 1991), compact airborne spectrographic imagery (CASI; 2002), light detection and ranging (LIDAR; 2011) and RapidEye data (2014 onward), changes in net area have been minor but significant redistribution has occurred, with this being attributed to both inland intrusion and seaward colonisation of mangroves. The greatest area changes have been associated with lower-stature mangroves dominated by Avicennia marina and Sonneratia alba, as determined from these datasets. Aerial surveys, conducted using a remote piloted aircraft (RPA) and fixed wing aircraft in September 2016, showed dieback of mangroves, with spaceborne RapidEye observations suggesting this occurred between late 2015 and 2016 and at the same time as the extensive mangrove losses reported in the Gulf of Carpentaria. Given the recent dieback and the associated need to better monitor and protect mangroves and proximal ecosystems in the World Heritage- and Ramsar-listed Kakadu National Park, the study recommends the development and implementation of a robust and long-term monitoring system that better utilises existing and ongoing earth observation and ground data, and is supported by a national approach.
Can owls be used to monitor the impacts of urbanisation? A cautionary tale of variable detection
Authors: Cooke Raylene , Grant Hannah , Ebsworth Isabel , Rendall Anthony R. , Isaac Bronwyn , White John G.
Published: December 2017

Context Due to their important ecological roles, predators are increasingly being suggested as targets for biodiversity studies investigating how they respond to landscape change and transformation. But there is limited literature investigating our capacity to accurately monitor changes in their occupancy. Aims To test the efficacy of playback surveys for monitoring owls as a basis for investigating change in owl occupancy over time. We ask whether playback is an effective tool, and whether it can be optimised to improve its utility. Methods Using the urban–forest interface of Melbourne, Australia, as a case study, we used playback techniques to survey for the presence of three owl species: the powerful owl (Ninox strenua); southern boobook (Ninox boobook); and eastern barn owl (Tyto javanica). Sites were repeat surveyed at least 16 times throughout the year and occupancy models were developed to establish how season and temperature influence nightly detection probabilities of owls. Key results All three species of owl were detected through playback survey approaches, but the detection probabilities varied greatly between species and across seasons and temperature conditions. Eastern barn owls are poor candidates for playback surveys due to their low detection probabilities. The southern boobook and powerful owl are responsive to playback, but detection probabilities are influenced by season and/or temperature conditions. To optimise survey approaches, southern boobooks should be surveyed during spring and summer and the powerful owl should be surveyed on nights where the minimum temperature is near 20°C. Conclusions Although there is considerable interest in using predators such as owls to monitor biodiversity impacts associated with landscape change, poor detection rates can limit their utility. However, optimising survey approaches that consider shifting detection probabilities under different conditions such as time of year or temperature may improve the utility of predators as surrogates in biodiversity monitoring. Implications Optimising survey approaches for owls considerably reduces the window of opportunity in which to conduct surveys. To counter this, the intensity of survey effort needs to be increased during key periods. The use of highly trained citizen science teams may be one effective way of delivering such an approach.
Encoding model of temporal processing in human visual cortex
Authors: Stigliani Anthony , Jeska Brianna , Grill-Spector Kalanit
Published: December 2017

Significance

How is temporal information processed in human visual cortex? To address this question, we used fMRI and a two temporal channel-encoding model. This approach not only explains cortical responses for time-varying stimuli ranging from milliseconds to seconds but finds differential temporal processing across human visual cortex. While motion-sensitive regions are dominated by transient responses, ventral regions that process the content of the visual input surprisingly show both sustained and transient responses, with the latter exceeding the former. This transient processing may foster rapid extraction of the gist of the scene. Importantly, our encoding approach marks a transformative advancement in the temporal resolution of fMRI, as it enables linking fMRI responses to the timescale of neural computations in cortex.
Efficient targeted DNA editing and replacement in
Chlamydomonas reinhardtii
using Cpf1 ribonucleoproteins and single-stranded DNA
Authors: Ferenczi Aron , Pyott Douglas Euan , Xipnitou Andromachi , Molnar Attila
Published: December 2017

Significance

Our findings establish a method of efficient, targeted genome editing in
Chlamydomonas reinhardtii
. We demonstrate an approach to bypass inefficient gene targeting via homologous recombination and achieve homology-directed DNA replacement in
C. reinhardtii
. In addition, we report CRISPR/Cpf1-mediated DNA editing efficiencies being boosted 500-fold through the use of single-stranded oligodeoxynucleotides (ssODNs) as repair templates. It remains to be determined whether Cpf1-induced staggered DNA cleavage enhances ssODN-mediated gene editing in a wider range of species and whether the underlying repair pathway(s) responsible is more broadly conserved.
Effect of removing Kupffer cells on nanoparticle tumor delivery
Authors: Tavares Anthony J. , Poon Wilson , Zhang Yi-Nan , Dai Qin , Besla Rickvinder , Ding Ding , Ouyang Ben , Li Angela , Chen Juan , Zheng Gang , Robbins Clinton , Chan Warren C. W.
Published: December 2017

Significance

Nanomaterials are developed for treating and diagnosing cancer, but only 0.7% (median) are delivered to a solid tumor. To address this delivery problem, we are examining each biological barrier to determine its impact on tumor delivery. Because the liver sequesters up to 70% of nanomaterials, in this study, we asked, if liver Kupffer cells were removed, what is the impact on tumor delivery? While we demonstrate that the tumor delivery increased up to 150 times, we achieved 2% for nanomaterials of different size, material, and tumor type. This suggests the need to focus on tumor pathophysiology to increase delivery efficiency, since this approach led to a greater availability of nanoparticles in the blood, but 98% did not accumulate in solid tumors.