bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effects of solar variability on planetary plasma environments and habitability
Authors: Bertucci César 
Published: July 2012

AbstractIntrinsic and induced planetary magnetospheres are the result of the transfer of energy and linear momentum between the solar wind and, respectively, the magnetic field and the atmospheres of solar system bodies. This transfer seems to be, however, more critical to the atmospheric evolution of unmagnetized objects such as Mars and Venus, as locally ionized planetary particles are accelerated by solar-wind induced electric fields, leading to atmospheric escape. The nature of the obstacle to the solar wind being different, intrinsic and induced magnetospheres respond differently to solar cycle changes in solar photon flux and solar wind properties. The influence of solar variability on planetary magnetospheres and its implications for atmospheric evolution based upon remote and in situ spacecraft measurements, and numerical simulations are discussed. In particular, the case of unmagnetized objects where non-thermal escape process might have played a role in their habitability conditions is considered.
Flares and habitability
Authors: Abrevaya Ximena C. , Cortón Eduardo , Mauas Pablo J. D. 
Published: July 2012

AbstractAt present, dwarf M stars are being considered as potential hosts for habitable planets. However, an important fraction of these stars are flare stars, which among other kind of radiation, emit large amounts of UV radiation during flares, and it is unknown how this events can affect life, since biological systems are particularly vulnerable to UV. In this work we evaluate a well known dMe star, EV Lacertae (GJ 873) as a potential host for the emergence and evolution of life, focusing on the effects of the UV emission associated with flare activity. Since UV-C is particularly harmful for living organisms, we studied the effect of UV-C radiation on halophile archaea cultures. The halophile archaea or haloarchaea are extremophile microorganisms, which inhabit in hypersaline environments and which show several mechanisms to cope with UV radiation since they are naturally exposed to intense solar UV radiation on Earth. To select the irradiance to be tested, we considered a moderate flare on this star. We obtained the mean value for the UV-C irradiance integrating the IUE spectrum in the impulsive phase, and considering a hypothetical planet in the center of the liquid water habitability zone. To select the irradiation times we took the most frequent duration of flares on this star which is from 9 to 27 minutes. Our results show that even after considerable UV damage, the haloarchaeal cells survive at the tested doses, showing that this kind of life could survive in a relatively hostile UV environment.
Parallels among the “music scores” of solar cycles, space weather and Earth's climate
Authors: Kolláth Zoltán , Oláh Katalin , van Driel-Gesztelyi Lidia 
Published: July 2012

AbstractSolar variability and its effects on the physical variability of our (space) environment produces complex signals. In the indicators of solar activity at least four independent cyclic components can be identified, all of them with temporal variations in their timescales.Time-frequency distributions (see Kolláth & Oláh 2009) are perfect tools to disclose the “music scores” in these complex time series. Special features in the time-frequency distributions, like frequency splitting, or modulations on different timescales provide clues, which can reveal similar trends among different indices like sunspot numbers, interplanetary magnetic field strength in the Earth's neighborhood and climate data.On the pseudo-Wigner Distribution (PWD) the frequency splitting of all the three main components (the Gleissberg and Schwabe cycles, and an ≈5.5 year signal originating from cycle asymmetry, i.e. the Waldmeier effect) can be identified as a “bubble” shaped structure after 1950. The same frequency splitting feature can also be found in the heliospheric magnetic field data and the microwave radio flux.
A cellular automaton model for coronal heating
Authors: Fuentes M. C. López , Klimchuk J. A. 
Published: July 2012

AbstractWe present a simple coronal heating model based on a cellular automaton approach. Following Parker's suggestion (1988), we consider the corona to be made up of elemental magnetic strands that accumulate magnetic stress due to the photospheric displacements of their footpoints. Magnetic energy is eventually released in small scale reconnection events. The model consists of a 2D grid in which strand footpoints travel with random displacements simulating convective motions. Each time two strands interact, a critical condition is tested (as in self-organized critical models), and if the condition is fulfilled, the strands reconnect and energy is released. We model the plasma response to the heating events and obtain synthetic observations. We compare the output of the model with real observations from Hinode/XRT and discuss the implications of our results for coronal heating.
Long recovery VLF perturbations associated with lightning discharges
Authors: Salut M. M. , Abdullah M. , Graf K. L. , Cohen M. B. , Cotts B. R. T. , Kumar Sushil 
Published: July 2012

Long D‐region ionospheric recovery perturbations are a recently discovered and poorly understood subcategory of early VLF events, distinguished by exceptionally long ionospheric recovery times of up to 20 min (compared to more typical ∼1 min recovery times). Characteristics and occurrence rates of long ionospheric recovery events on the NWC transmitter signal recorded at Malaysia are presented. 48 long recovery events were observed. The location of the causative lightning discharge for each event is determined from GLD360 and WWLLN data, and each discharge is categorized as being over land or sea. Results provide strong evidence that long recovery events are attributed predominately to lightning discharges occurring over the sea, despite the fact that lightning activity in the region is more prevalent over land. Of the 48 long recovery events, 42 were attributed to lightning activity over water. Analysis of the causative lightning of long recovery events in comparison to all early VLF events reveals that these long recovery events are detectable for lighting discharges at larger distances from the signal path, indicating a different scattering pattern for long recovery events.
Nitrification expanded: discovery, physiology and genomics of a nitrite-oxidizing bacterium from the phylum Chloroflexi
Authors: Sorokin Dimitry Y , Lücker Sebastian , Vejmelkova Dana , Kostrikina Nadezhda A , Kleerebezem Robbert , Rijpstra W Irene C , Damsté Jaap S Sinninghe , Le Paslier Denis , Muyzer Gerard , Wagner Michael , van Loosdrecht Mark C M , Daims Holger 
Published: July 2012

Abstract
Nitrite-oxidizing bacteria (NOB) catalyze the second step of nitrification, a major process of the biogeochemical nitrogen cycle, but the recognized diversity of this guild is surprisingly low and only two bacterial phyla contain known NOB. Here, we report on the discovery of a chemolithoautotrophic nitrite oxidizer that belongs to the widespread phylum Chloroflexi not previously known to contain any nitrifying organism. This organism, named Nitrolancetus hollandicus, was isolated from a nitrifying reactor. Its tolerance to a broad temperature range (25–63 °C) and low affinity for nitrite (Ks=1 mm), a complex layered cell envelope that stains Gram positive, and uncommon membrane lipids composed of 1,2-diols distinguish N. hollandicus from all other known nitrite oxidizers. N. hollandicus grows on nitrite and CO2, and is able to use formate as a source of energy and carbon. Genome sequencing and analysis of N. hollandicus revealed the presence of all genes required for CO2 fixation by the Calvin cycle and a nitrite oxidoreductase (NXR) similar to the NXR forms of the proteobacterial nitrite oxidizers, Nitrobacter and Nitrococcus. Comparative genomic analysis of the nxr loci unexpectedly indicated functionally important lateral gene transfer events between Nitrolancetus and other NOB carrying a cytoplasmic NXR, suggesting that horizontal transfer of the NXR module was a major driver for the spread of the capability to gain energy from nitrite oxidation during bacterial evolution. The surprising discovery of N. hollandicus significantly extends the known diversity of nitrifying organisms and likely will have implications for future research on nitrification in natural and engineered ecosystems.
A biomolecular isolation framework for eco-systems biology
Authors: Roume Hugo , EL Muller Emilie , Cordes Thekla , Renaut Jenny , Hiller Karsten , Wilmes Paul 
Published: July 2012

Abstract
Mixed microbial communities are complex, dynamic and heterogeneous. It is therefore essential that biomolecular fractions obtained for high-throughput omic analyses are representative of single samples to facilitate meaningful data integration, analysis and modeling. We have developed a new methodological framework for the reproducible isolation of high-quality genomic DNA, large and small RNA, proteins, and polar and non-polar metabolites from single unique mixed microbial community samples. The methodology is based around reproducible cryogenic sample preservation and cell lysis. Metabolites are extracted first using organic solvents, followed by the sequential isolation of nucleic acids and proteins using chromatographic spin columns. The methodology was validated by comparison to traditional dedicated and simultaneous biomolecular isolation methods. To prove the broad applicability of the methodology, we applied it to microbial consortia of biotechnological, environmental and biomedical research interest. The developed methodological framework lays the foundation for standardized molecular eco-systematic studies on a range of different microbial communities in the future.
Tier‐based pricing for institutions: a new, e‐based pricing model
Authors: CHESLER Adam , KING Susan 
Published: July 2012

ABSTRACTThe American Chemical Society (ACS) recently introduced a new pricing model for the digital versions of its journals. Our primary goals were to completely decouple electronic and print subscriptions, to broaden access to content globally, and to address the needs of different market segments so that similar institutions were charged equivalent amounts for comparable usage/need of ACS journals. A cross‐departmental team, with the assistance of independent consultants, analyzed multiple layers of customer data before the new model was built. As a result, we have implemented a two‐faceted model that separately addresses academic and non‐academic subscribers, and that also enables us to assess the relative value of each journal within our portfolio. The process started in 2005 and took over two years to complete, involving numerous staff members and incorporating input from customers worldwide across all market sectors, as well as subscription agents. The model was announced in spring 2007, and applied to 2008 subscriptions. The lessons learned are applicable to any publisher considering a review of its pricing model.
Local structure and p–d hybridization of Mn-doped In2O3 films
Authors: An Yukai , Feng Deqiang , Duan Lingshen , Wu Zhonghua , Liu Jiwen 
Published: July 2012

Abstract
Mn-doped In2O3 films were deposited on Si (1 0 0) substrates by the RF-magnetron sputtering technique. The influence of Mn-doping concentration on the local structure and degree of p–d hybridization was investigated by x-ray absorption spectroscopy at the Mn K-edge and L2,3-edge. The results show that Mn ions dissolve in In2O3 and substitute for In3+ sites in the +2 valence states. With the increase in Mn-doping concentration, the Mn–O bonding distance increases monotonically, but integrated intensities of L2,3 edges increase first and then decrease. It can be concluded that there exists an optimal Mn–O bonding distance for the transition probabilities from the 2p state to the p–d hybridization state, which results in increasing degree of p–d hybridization. So the Mn-doping concentration has a significant effect on the local structure and degree of p–d hybridization in Mn-doped In2O3 films.
Role of singular layers in the plasma response to resonant magnetic perturbations
Authors: Waelbroeck F.L. , Joseph I. , Nardon E. , Bécoulet M. , Fitzpatrick R. 
Published: July 2012

Abstract
The response of an H-mode plasma to magnetic perturbations that are resonant in the edge is evaluated using a fluid model. With two exceptions, the plasma rotation suppresses the formation of magnetic islands, holding their widths to less than a tenth of those predicted by the vacuum approximation. The two exceptions are at the foot of the pedestal, where the plasma becomes more resistive, and at the surface where the perpendicular component of the electron velocity reverses. The perturbations exert a force on the plasma so as to brake the perpendicular component of the electron rotation. In the pedestal, the corresponding Maxwell stress drives the radial electric field in such a way as to accelerate ion rotation. Despite the suppression of the islands, the perturbations give rise to particle fluxes caused by magnetic flutter, with a negligible contribution from E × B convection. In the pedestal, the fluxes are such as to reduce the density.
Robust sawtooth period control based on adaptive online optimization
Authors: Bolder J.J. , Witvoet G. , de Baar M.R. , van de Wouw N. , Haring M.A.M. , Westerhof E. , Doelman N.J. , Steinbuch M. 
Published: July 2012

Abstract
The systematic design of a robust adaptive control strategy for the sawtooth period using electron cyclotron current drive (ECCD) is presented. Recent developments in extremum seeking control (ESC) are employed to derive an optimized controller structure and offer practical tuning guidelines for its parameters. In this technique a cost function in terms of the desired sawtooth period is optimized online by changing the ECCD deposition location based on online estimations of the gradient of the cost function. The controller design does not require a detailed model of the sawtooth instability. Therefore, the proposed ESC is widely applicable to any sawtoothing plasma or plasma simulation and is inherently robust against uncertainties or plasma variations. Moreover, it can handle a broad class of disturbances. This is demonstrated by time-domain simulations, which show successful tracking of time-varying sawtooth period references throughout the whole operating space, even in the presence of variations in plasma parameters, disturbances and slow launcher mirror dynamics. Due to its simplicity and robustness the proposed ESC is a valuable sawtooth control candidate for any experimental tokamak plasma, and may even be applicable to other fusion-related control problems.
Experimental observations of plasma edge magnetic field response to resonant magnetic perturbation on the TEXTOR Tokamak
Authors: Yang Y. , Liang Y. , Sun Y. , Zhang T. , Pearson J. , Xu Y. 
Published: July 2012

Abstract
The plasma response to a resonant magnetic perturbation (RMP) is experimentally measured on the TEXTOR tokamak using a fast movable magnetic probe. It is shown that, due to the plasma response, the magnetic field significantly differs from the vacuum field. Clear linear and non-linear responses to RMP are observed by varying the intensity of these perturbations or the plasma edge safety factor. Both the radial profile evolution and the dependence of plasma response on the edge safety factor show a stronger resonant effect when the RMP rotates at 5 kHz in the counter-current direction.
An analysis of lower hybrid grill coupling using an efficient full wave code
Authors: Preinhaelter Josef , Urban Jakub , Vahala Linda , Vahala George 
Published: July 2012

Abstract
Lower hybrid (LH) waves are very important for heating and current drive in tokamaks. Phased arrays of rectangular waveguides, generally called grills, are typically used as launchers. We develop a code which solves, in the 3D geometry of the grill structure, the problem of efficient coupling: the power density spectrum of the emitted waves, the power reflection coefficient, the power lost by the waves launched in the inaccessible region and the directivity of the waves transmitted into the accessible region. The code is also able to determine the 3D electric field in front of the grill. An efficient adaptive full wave solver is used to determine the wave propagation in a 1D plasma slab geometry. To evaluate the very large number of 2D k-space infinite integrals for the coupling elements, we have developed a method based on high order Gaussian quadratures combined with 2D B-splines in the accessible region for the plasma related part of the integrands. This method is well suited to handle large structures and many modes because the computational time is only weakly dependent on the size of the problem. An iterative evaluation of the integrands in the inaccessible region is adopted to handle the presently overlooked near singular behaviour of the integrands as well as the spectral power density associated with the eigenmodes. The role of collisions is clarified in this context.
The code is applied to several COMPASS grills operating either at 1.3 GHz or at 3.7 GHz. First we thouroughly analyse the original 1.3 GHz, 8-waveguide conventional grill at various waveguide phasing. Then, the coupling of two grill designs for 3.7 GHz is solved. The suitability of all the grills is discussed, showing compatible grill and plasma parameter ranges.
Effect of nebivolol on outcome in elderly patients with heart failure and atrial fibrillation: insights from SENIORS
Authors: Mulder Bart A. , van Veldhuisen Dirk J. , Crijns Harry J.G.M. , Böhm Michael , Cohen‐Solal Alain , Babalis Daphne , Roughton Michael , Flather Marcus D. , Coats Andrew J.S. , Van Gelder Isabelle C. 
Published: July 2012

AimsBeneficial effects of beta‐blockade remain unclear in heart failure patients who have atrial fibrillation (AF), especially in the elderly. We evaluated the effect of nebivolol on cardiovascular outcomes in elderly patients with heart failure and AF.Methods and resultsThe SENIORS trial showed an overall benefit of nebivolol compared with placebo in 2128 heart failure patients >70 years of age. At baseline, AF was present in 738 (34.7%) patients. The primary outcome was all‐cause mortality or cardiovascular hospitalizations. After 21 months, the cumulative incidence of the primary outcome was significantly more common in patients with AF compared with those with sinus rhythm (38.5% vs. 30.4%, respectively, P < 0.001). In patients with AF, nebivolol had no beneficial effect on the primary outcome [nebivolol vs. placebo, 37.1% vs. 39.8%, hazard ratio (HR) 0.92, 95% confidence interval (CI), 0.73–1.17, P = 0.46], in contrast to patients with sinus rhythm (28.1% vs. 32.9%, in the nebivolol vs. placebo group, respectively, HR 0.82, 95% CI 0.67–0.99, P = 0.049). In patients with AF, the primary outcome was similar in the impaired and preserved left ventricular ejection fraction (LVEF) groups (39.0% with LVEF ≤35% vs. 37.3% in patients with LVEF > 35%). There was also no evidence of benefit of nebivolol in AF patients stratified by LVEF.ConclusionNebivolol failed to improve outcomes in elderly patients with stable heart failure and co‐existing AF, irrespective of LVEF. Furthermore, in patients with AF, outcome was comparable between patients with preserved and impaired LVEF.
The response of herring to high crowding densities in purse-seines: survival and stress reaction
Authors: Tenningen Maria , Vold Aud , Olsen Rolf Erik 
Published: July 2012

Abstract
Tenningen, M., Vold, A., and Olsen, R. E. 2012. The response of herring to high crowding densities in purse-seines: survival and stress reaction. – ICES Journal of Marine Science, 69: . To study the effects of crowding in purse-seines on the survival and stress response of herring (Clupea harengus), large-scale field experiments were conducted in the North Sea during 2008 and 2009. The mortality was 28% at a crowding density of 221 kg m−3 and increased further with increasing density. Crowding densities <150 kg m−3 did not result in any additional mortality compared with the control group (0.9–2.0%). Smaller herring and herring with a lower condition factor were more vulnerable to the effects of crowding. Blood analyses showed a significant increase in cortisol, lactate, and blood ions in the crowded fish. Lactate returned to control levels 2 d post-stress, whereas cortisol and blood ion levels continued to increase during the 4- to 5-d monitoring period. Furthermore, plasma glucose appeared to be substantially reduced at the end of the trial, indicating that the herring were incapable of restoring homeostasis and were approaching energy exhaustion. These results provide important information about the crowding densities that can be tolerated in the purse-seine fisheries for herring and will benefit future development of guidelines for purse-seine slipping operations.
Angioadnexocentric nevus
Authors: HASHIMOTO Ken , AMANO Masahiro , SETOYAMA Mitsuru 
Published: July 2012

AbstractAn association of melanocytic nevus with eccrine glands has been well‐documented and well‐known as eccrine‐centered nevus. Non‐giant congenital nevi sometimes contain angiocentric and/or adnexocentric growth of nevus cells. Blood vessels are the most prominent site of nevus cell infiltration and propagation. In our specimen, the second was eccrine ducts. These selective sites of infiltration gave rise to a linear pattern of nevus cell distribution. Upon cursory examination at low magnification, vascular pathologies such as lymphocytic perivasculitis and particularly “coat‐sleeve‐like” pattern of erythema annulare centrifugum were suggested. S‐100 immunostained perivascular and periductal lymphocytoid cells while CD3, 4 and 8 for T cells, and CD20 and 79a for B cells, were all negative. S‐100 detected some invasive behavior of nevus cells penetrating into the vascular and ductal walls. However, Ki‐67 was negative in all cells, suggesting a benign nature of this lesion. It is postulated that intradermal nevus cells of fetal skin freely migrate through mesenchymal tissue and stop when they hit barriers such as blood vessels and eccrine ducts and propagate in situ. How does this random migration theory explain the blood vessels and eccrine ducts getting the largest share of nevus cells? It is because they are the largest barriers of fetal dermis.