bluuebunny/crossref_metadata_2025 huggingface dataset:
Spectroscopic Binaries Among λ Bootis-type Stars
Authors: Paunzen Ernst , Fraga Luciano , Heiter Ulrike , Iliev Ilian Kh. , Kamp Inga , Pintado Olga
Published: April 2012

The small group of λ Bootis stars comprises late B to early F-type stars, with moderate to extreme (up to a factor 100) surface under-abundances of most Fe-peak elements and solar abundances of lighter elements (C, N, O, and S). The main mechanisms responsible for this phenomenon are atmospheric diffusion, meridional mixing, and accretion of material from their surroundings. Especially spectroscopic binary (SB) systems with λ Bootis-type components are very important to investigate the evolutionary status and accretion process in more details. Because also δ Scuti type pulsation was found for several members, it gives the opportunity to use the tools of astroseismology for further investigations. We present the results of our long term efforts of detailed abundance analysis, orbital parameter estimation and photometric time series analysis for five well investigated SB systems.
Characterizing New Eclipsing Binaries Identified from STEREO Photometry
Authors: Markov Harry , Tsvetanov Zlatan , Iliev Ilian , Stateva Ivanka , Markova Nevena
Published: April 2012

Since 2010, a program to explore new eclipsing binary systems identified from STEREO photometry has been in progress. Our first results are presented here: light curves and high resolution spectra taken with Coudé spectrograph (National Astronomical Observatory Rozhen) and ARC Échelle spectrometer (ARCES, Apache Point Observatory).
Panel Discussion II
Authors: Allard F. , Batten A. , Budding E. , Devinney E. , Eggleton P. , Hatzes A. , Hubeny I. , Kley W. , Lammer H. , Linnell A. , Trimble V. , Wilson R. E.
Published: April 2012

I. Hubeny Today, the discussion will be open to the general audience. In Sessions C, D, and E, we have talked about models and modelling techniques so I expect the discussion will focus on these topics.
TODCOR – Two-Dimensional Correlation
Authors: Zucker Shay
Published: April 2012

TODCOR is a TwO-Dimensional CORrelation technique to measure radial velocities of the two components of a spectroscopic binary. Assuming the spectra of the two components are known, the technique correlates an observed binary spectrum against a combination of the two spectra with different shifts. TODCOR measures simultaneously the radial velocities of the two stars by finding the maximum correlation. The main use of the technique has been to turn single-lined binaries into double-lined systems. This helps to explore the binary mass-ratio distribution, especially the low-mass regime, where the secondaries are usually very faint and therefore hard to detect. The technique has been generalized to study multi-order spectra, and also triple- and quadruple-lined systems. It has several applications in studying extrasolar planets and in the future may even help to dynamically measure stellar masses of binaries through relativistc effects.
Renormalization of KOREL-Decomposed SB2 Spectra
Authors: Lehmann Holger , Tkachenko Andrew
Published: April 2012

We introduce a new computer program that is able to determine the flux ratio between the components of SB2 stars from time series of composite spectra. The spectra of the components are decomposed using the KOREL program and compared to synthetic spectra computed on a grid of fundamental stellar parameters. In the result, we obtain the optimized stellar parameters together with the flux ratio. The program is tested and applied to the oscillating eclipsing binary KIC 10661783 observed by the Kepler satellite mission.
A Search for the Secondary Spectrum of ε Aurigae
Authors: Bennett P. D. , Harmanec P. , Chadima P. , Yang S.
Published: April 2012

The enigmatic long period (P = 27.1 yr) eclipsing binary, ε Aurigae, recently emerged from its 2009–2011 eclipse. We have analyzed out-of-eclipse observations (Chadima et al. 2010) obtained over the past 17 years: 306 medium-resolution, high S/N, spectroscopic observations from 6300–6700 Å. Of these, 105 spectra were obtained at the Dominion Astrophysical Observatory (DAO) near Victoria, Canada, from 1994–2010, and 201 spectra were obtained at Ondřejov Observatory (OND), from 2006–2010. Analyzing these data, Chadima et al. (these proceedings) reported on a positive, but ultimately spurious, detection of a secondary spectrum. Their attempts at disentangling the binary spectra were foiled by line profile variations of the F star primary. The 6300-6700 Å spectral region contains several strong stellar lines but space limitations allow us to present only the results for Si II 6347 Å. We examine the centroids and higher moments of this prominent F star spectral line for any evidence of a secondary spectrum. Even if secondary contributions are blended with the F star lines, contamination by the secondary star should produce a centroid shift that is anti-correlated with the orbit of the F star primary.
Dependence of Circumsubstellar Disk SEDs on System Inclination
Authors: Zakhozhay Olga
Published: April 2012

The spectral energy distributions (SEDs) have being simulated for 1120 systems that contain brown dwarfs with different physical parameters and protoplanetary disks that are inclined at different angles. The SED's shape dependence on disk inclination toward the observer is discussed.
Planetary Dynamics in the α Centauri System: Lyapunov Spectra and Long-term Behaviour
Authors: Popova E. A. , Shevchenko I. I.
Published: April 2012

The stability of planetary motion in the binary system α Cen A–B is studied. Lyapunov spectra of the motion of the system with a single massive planet are computed on a fine grid of the initial data, and, by means of statistical analysis of the obtained data arrays, chaotic domains are identified in the “pericentric distance — eccentricity” initial data space for the planetary orbit. Association with the initial data domains for the orbits exhibiting close encounters with central stars and for the orbits exhibiting long-term escape is investigated.
Binary Systems Within Star Clusters
Authors: Paunzen Ernst , Stütz Christian , Baumann Bernhard
Published: April 2012

WEBDA (http://www.univie.ac.at/webda) is a site devoted to observational data of stellar clusters in the Milky Way and the Small Magellanic Cloud. It is intended to provide a reliable presentation of the available data and knowledge about these objects. The success of WEBDA is documented by its worldwide usage and the related acknowledgements in the literature: more than 650 refereed publications within the last twelve years acknowledged its use. It collects all published data for stars in open clusters that may be useful either to determine membership, or to study the stellar content and properties of the clusters.

The database content includes astrometric data in the form of coordinates, rectangular positions, and proper motions, photometric data in the major systems in which star clusters have been observed, but also spectroscopic data like spectral classification, radial velocities, and rotational velocities. It also contains miscellaneous types of supplementary data like membership probabilities, orbital elements of spectroscopic binaries, and periods for different kinds of variable stars as well as an extensive bibliography. Several powerful tools help to plot, query and extract the data, which can be directly retrieved via http. At the time of writing, about four million individual measurements have been included in the database. The Star Clusters Young & Old Newsletter (SCYON), a bi-monthly newsletter devoted to star cluster research with about 600 subscribers, is hosted in parallel with the database.

We present the current and upcoming new interface and tools, which are needed to visualize and analyze the increasing amount of data from all-sky surveys, and deeper investigations of binary systems, low mass dwarfs, as well as planet-hosting stars.
The Origin and Evolution of the Black Hole Binary XTE J1118+480
Authors: González Hernández Jonay I. , Rebolo Rafael , Casares Jorge
Published: April 2012

Black hole X-ray binaries with large mass ratios and short orbital periods are expected to change their orbital period due to magnetic breaking, mass loss, gravitational radiation, or mass evaporation of the black hole in alternative descriptions of gravity, like in braneworld gravity scenarios.

The black hole X-ray binary XTE J1118+480, consisting of a late-type secondary star orbiting a ~ 8 M⊙ black hole in a 4.1-hr period, offers a unique opportunity to test these models. New spectroscopic data allow us to determine the time of the inferior conjunction of the secondary star at different epochs. Observations over a 10 year span will provide constraints on the rate of any orbital period change.

We present here a preliminary radial velocity curve obtained with the 10.4m GTC telescope equipped with OSIRIS medium-resolution spectrograph, as part of an ongoing long-term program to study the orbital period evolution in this binary.
An Unusual Low State of the Polar AR UMa
Authors: Kjurkchieva Diana P. , Marchev Dragomir V.
Published: April 2012

Our photometric CCD observations of the short-period cataclysmic star AR UMa in 2008 during its low state revealed light variability with a bigger period (by around 10%) and considerably smaller amplitudes than the previous ones. The light curve had a single-wave shape, opposite to the previously observed low states which revealed doubled-humped shape.
Exoplanet Upper Atmosphere Environment Characterization
Authors: Lammer Helmut , Kislyakova Kristina G. , Odert Petra , Leitzinger Martin , Khodachenko Maxim L. , Holmström Mats , Hanslmeier Arnold
Published: April 2012

The intense stellar SXR and EUV radiation exposure at “Hot Jupiters” causes profound responses to their upper atmosphere structures. Thermospheric temperatures can reach several thousands of Kelvins, which result in dissociation of H2 to H and ionization of H to H+. Depending on the density and orbit location of the exoplanet, as a result of these high temperatures the thermosphere expands dynamically up to the Roche lobe, so that geometric blow-off with large mass loss rates and intense interaction with the stellar wind plasma can occur. UV transit observations together with advanced numerical models can be used to gain knowledge on stellar plasma and the planet's magnetic properties, as well as the upper atmosphere.
3D Models of Exoplanet Atmospheres
Authors: Dobbs-Dixon Ian
Published: April 2012

Dynamical models of strongly irradiated gas-giant atmospheres exhibit a range of behavior, the nature of which depends on both the adopted parameters and the adopted numerical model. Discerning the correct choice of physical parameters and modeling philosophy can be difficult. Here, I present a series of wavelength-dependent transmission spectra for the giant planet HD209458b based on 3D radiative hydrodynamical models for a range of kinematic viscosities. While flow patterns and temperature distributions can vary significantly, disk-averaged phase curves mask much of this information. Transmission spectra, on the other hand, probe the day-night transition where advective contributions dominate and differences are often most pronounced. Transmission spectra illustrate noticeable changes, especially when comparing the differences between transmission spectra of eastern and western hemispheres, as might be seen during ingress and egress.
Gas Dynamic Simulation of the Star-Planet Interaction using a Binary Star Model
Authors: Ionov D. E. , Bisikalo D. V. , Kaygorodov P. V. , Shematovich V. I.
Published: April 2012

We have performed numerical simulations of the interaction between a “hot Jupiter” planet and gas of the stellar wind using a numerical code developed for investigations of binary stars. With this code, we have modeled the structure of the gaseous flow in the system HD 209458. The results have been used to explain observations of this system performed with the COS instrument on-board the HST.
Panel Discussion IV
Authors: Allard F. , Batten A. , Budding E. , Devinney E. , Eggleton P. , Hatzes A. , Hubeny I. , Kley W. , Lammer H. , Linnell A. , Trimble V. , Wilson R. E.
Published: April 2012

I. Hubeny Welcome to the last panel meeting. We invite general comments either from the audience or from the panelists.

V. Trimble Well, Mercedes started us with a vocabulary item and I think I would like to end with a vocabulary item. When they were first discovered, we called them ‘extra solar system planets’ which was descriptive and fine, but it's just rather cumbersome. At some point they became ‘extra solar planets.’ Now I have never seen a planet inside the Sun. And therefore ‘extrasolar’ is not a good descriptor. ‘Exoplanets’ is OK, but now that there are so many of them that perhaps they are simply ‘the planets.’ When you want to specialize to ours, you could say ‘solar system planets.’ Think how much ink it would save.
Transboundary and Global Environmental Issues: The Role of asean
Authors: Kheng-Lian Koh
Published: April 2012

This contribution focuses on the challenges that regional organizations face as they are increasingly confronted with, and need to respond to, transboundary and global environmental problems. Ever more frequently, environmental issues that begin as matters of national concern rapidly become transboundary in scope. As exemplified by the outbreak of avian flu, integrated national, regional and international efforts are necessary to tackle transboundary environmental issues which, by their very definition, call for a coordinated effort. This article will concentrate on the impact of transboundary environmental challenges on the objectives and functions of the Association of South East Asian Nations (asean).
Atlantic forcing of the Mediterranean oligotrophy
Authors: Huertas I. E. , Ríos A. F. , García‐Lafuente J. , Navarro G. , Makaoui A. , Sánchez‐Román A. , Rodriguez‐Galvez S. , Orbi A. , Ruíz J. , Pérez F. F.
Published: April 2012

The Mediterranean Sea shows a peculiar anomaly in its nutrient pattern compared to the global ocean, as there is decrease in nutrient concentration from west to east. This feature has been attributed to the antiestuarine circulation at the Strait of Gibraltar, where an eastward flow of Atlantic nutrient‐poor surface waters is compensated by a westward countercurrent of Mediterranean nutrient‐rich deep waters. This water exchange has been suggested as the ultimate cause for the oligotrophy of the Mediterranean basin, even though only a few studies have accurately examined the magnitude of the nutrient flux through the Strait of Gibraltar. In this work, data from the Gibraltar Fixed Time series (GIFT) between 2005 and 2008 were used to assess nutrient distributions. Applying a two‐layer model of water mass exchange and using the Mediterranean outflow recorded in situ, the net export of nutrients from the Mediterranean to the Atlantic was calculated as 139 and 4.8 Gmol yr−1 of nitrate and phosphate, respectively. The results also demonstrated that the Atlantic inflow is not nutrient depleted and in particular contains significant levels of phosphate, which is the limiting factor for biological productivity in the eastern Mediterranean. The distribution of the quasi‐conservative parameter N* in the western and eastern basins indicated that nitrate‐deficient surface waters are transformed into phosphate‐deficient bottom waters by internal cycling processes. Therefore, phosphate depletion in the Mediterranean does not have its origin in the entry of a phosphorus‐impoverished Atlantic inflow through the Strait of Gibraltar.
Hydrothermal activity in the Northwest Lau Backarc Basin: Evidence from water column measurements
Authors: Lupton J. E. , Arculus R. J. , Resing J. , Massoth G. J. , Greene R. R. , Evans L. J. , Buck N.
Published: April 2012

The Northwest Lau Backarc Basin, consisting of the Northwest Lau Spreading Center (NWLSC) and the Rochambeau Rifts (RR), is unique in having elevated 3He/4He ratios (up to 28 Ra) in the erupted lavas, clearly indicating a hot spot or ocean island basalt (OIB)‐type signature. This OIB‐type helium signature does not appear in any other part of the Lau Basin. Water column plume surveys conducted in 2008 and 2010 identified several sites of active hydrothermal discharge along the NWLSC‐RR and showed that the incidence of hydrothermal activity is high, consistent with the high spreading rate of ∼100 mm/year. Hydrocasts into the Central Caldera and Southern Caldera of the NWLSC detected elevated3He/4He (δ3He = 55% and 100%, respectively), trace metals (TMn, TFe), and suspended particles, indicating localized hydrothermal venting at these two sites. Hydrocasts along the northern rift zone of the NWLSC also had excess δ3He, TMn, and suspended particles suggesting additional sites of hydrothermal activity. The RR are dominated by Lobster Caldera, a large volcano with four radiating rift zones. Hydrocasts into Lobster Caldera in 2008 detected high δ3He (up to 239%) and suspended particle and TMn signals, indicating active venting within the caldera. A repeat survey of Lobster in 2010 confirmed the site was still active two years later. Plumes at Lobster Caldera and Central Caldera have end‐member3He/4He ratios of 19 Ra and 11 Ra, respectively, confirming that hot spot‐type helium is also present in the hydrothermal fluids.
Toward understanding of differences in current cloud retrievals of ARM ground‐based measurements
Authors: Zhao Chuanfeng , Xie Shaocheng , Klein Stephen A. , Protat Alain , Shupe Matthew D. , McFarlane Sally A. , Comstock Jennifer M. , Delanoë Julien , Deng Min , Dunn Maureen , Hogan Robin J. , Huang Dong , Jensen Michael P. , Mace Gerald G. , McCoy Renata , O'Connor Ewan J. , Turner David D. , Wang Zhien
Published: April 2012

Accurate observations of cloud microphysical properties are needed for evaluating and improving the representation of cloud processes in climate models and better estimate of the Earth radiative budget. However, large differences are found in current cloud products retrieved from ground‐based remote sensing measurements using various retrieval algorithms. Understanding the differences is an important step to address uncertainties in the cloud retrievals. In this study, an in‐depth analysis of nine existing ground‐based cloud retrievals using ARM remote sensing measurements is carried out. We place emphasis on boundary layer overcast clouds and high level ice clouds, which are the focus of many current retrieval development efforts due to their radiative importance and relatively simple structure. Large systematic discrepancies in cloud microphysical properties are found in these two types of clouds among the nine cloud retrieval products, particularly for the cloud liquid and ice particle effective radius. Note that the differences among some retrieval products are even larger than the prescribed uncertainties reported by the retrieval algorithm developers. It is shown that most of these large differences have their roots in the retrieval theoretical bases, assumptions, as well as input and constraint parameters. This study suggests the need to further validate current retrieval theories and assumptions and even the development of new retrieval algorithms with more observations under different cloud regimes.
Influence of fair‐weather cumulus clouds on isoprene chemistry
Authors: Kim S.‐W. , Barth M. C. , Trainer M.
Published: April 2012

Fair‐weather cumulus clouds are not resolved in regional‐ and global‐scale atmospheric chemistry models because their horizontal extent is less than the horizontal resolution of the model. A Large‐Eddy Simulation (LES) model, with finer grid resolution, can resolve the energy containing turbulent eddies and fair‐weather cumulus clouds. Isoprene, which is mainly emitted from deciduous forests and plays a significant role in producing ozone, has a chemical lifetime similar to the boundary layer turbulence turnover time, indicating that turbulent transport, cloud processes, and chemistry are all potentially important for the prediction of ambient isoprene concentrations. The LES model coupled with chemistry developed in this study is an ideal tool to examine the influence of fair‐weather cumulus clouds on isoprene chemistry. With a LES model that includes a moderately complex gas‐phase chemical mechanism of isoprene oxidation, we find enhancement of isoprene, methacrolein, and methylvinyl ketone in the cloud layer while changes in these chemical species' mixing ratios in the subcloud layer relative to the cloud‐free case vary depending on the chemical lifetimes. We demonstrate that nitrogen oxides put into the system can modulate the chemical lifetimes of isoprene and related chemical species, which in turn changes the vertical distribution of the chemical species. For high NOx conditions, ozone in the subcloud layer for the cloudy case is ∼5 ppbv lower than that for the cloud‐free case, suggesting potential positive ozone bias in large‐scale models that do not include fair‐weather cumulus cloud processes.
Tumour suppressor genes in chemotherapeutic drug response
Authors: Lai Dulcie , Visser-Grieve Stacy , Yang Xiaolong
Published: April 2012

Since cancer is one of the leading causes of death worldwide, there is an urgent need to find better treatments. Currently, the use of chemotherapeutics remains the predominant option for cancer therapy. However, one of the major obstacles for successful cancer therapy using these chemotherapeutics is that patients often do not respond or eventually develop resistance after initial treatment. Therefore identification of genes involved in chemotherapeutic response is critical for predicting tumour response and treating drug-resistant cancer patients. A group of genes commonly lost or inactivated are tumour suppressor genes, which can promote the initiation and progression of cancer through regulation of various biological processes such as cell proliferation, cell death and cell migration/invasion. Recently, mounting evidence suggests that these tumour suppressor genes also play a very important role in the response of cancers to a variety of chemotherapeutic drugs. In the present review, we will provide a comprehensive overview on how major tumour suppressor genes [Rb (retinoblastoma), p53 family, cyclin-dependent kinase inhibitors, BRCA1 (breast-cancer susceptibility gene 1), PTEN (phosphatase and tensin homologue deleted on chromosome 10), Hippo pathway, etc.] are involved in chemotherapeutic drug response and discuss their applications in predicting the clinical outcome of chemotherapy for cancer patients. We also propose that tumour suppressor genes are critical chemotherapeutic targets for the successful treatment of drug-resistant cancer patients in future applications.
Multilingual Prosperity–Inspiration Outsourced!
Authors: Chakraborty Rahul
Published: April 2012

With the advent of broader scientific and socio-educational motivations across the globe, cross-cultural and cross-linguistic inspirations are increasingly prevalent in the professions of speech-language pathology and audiology. This essay presents a sketch of a multilingual community, India. An overview of the general educational structure and the special education system has been presented to acknowledge the sensitivity of the government and non-government sectors towards multiple languages. Finally, an attempt has been made to present some socio-linguistic questions that are inherently tied to potential globalization of the professions of speech-language pathology and audiology.
Audiology Services in India
Authors: Mandke Kalyani , Deshpande Rashmi
Published: April 2012

Hearing impairment is common throughout the world, and it is estimated that 50% of all deafness and hearing impairment is preventable. The World Health Organization (WHO, 1999) estimates that there are 255 million people worldwide with a hearing impairment; of those, two-thirds live in the developing countries. Although hearing loss is not a death causing disease, the implication of hearing impairment for the individual, family, and community is tremendous. The far-reaching implications of hearing loss, both in terms of development of communication skills as well as social, economic, and quality of life issues, warrant highlighting the magnitude and severity of the problem. This disability cannot be “seen” and, therefore, has been low-profile. At the same time, hearing loss programs in India are less developed than programs for individuals diagnosed with blindness. It is well documented that hearing loss and deafness is preventable, provided it is detected early and managed properly through appropriate health education and program development.
Plasma potential mapping of high power impulse magnetron sputtering discharges
Authors: Rauch Albert , Mendelsberg Rueben J. , Sanders Jason M. , Anders André
Published: April 2012

Pulsed emissive probe techniques have been used to determine the plasma potential distribution of high power impulse magnetron sputtering (HiPIMS) discharges. An unbalanced magnetron with a niobium target in argon was investigated for a pulse length of 100 μs at a pulse repetition rate of 100 Hz, giving a peak current of 170 A. The probe data were recorded with a time resolution of 20 ns and a spatial resolution of 1 mm. It is shown that the local plasma potential varies greatly in space and time. The lowest potential was found over the target’s racetrack, gradually reaching anode potential (ground) several centimeters away from the target. The magnetic presheath exhibits a funnel-shaped plasma potential resulting in an electric field which accelerates ions toward the racetrack. In certain regions and times, the potential exhibits weak local maxima which allow for ion acceleration to the substrate. Knowledge of the local E and static B fields lets us derive the electrons’ E×B drift velocity, which is about 105 m/s and shows structures in space and time.
Thermal insulating layer on a conducting substrate. Analysis of thermoreflectance experiments
Authors: Frétigny C. , Duquesne J.-Y. , Fournier D. , Xu F.
Published: April 2012

Thermoreflectance experiments are sensitive to the thermal properties of thin layers deposited on substrates (conductivity and diffusivity). However, retrieving these properties from experimental data remains a difficult issue. The case of a conducting layer deposited on an insulating substrate was studied previously. We present here a mathematical and experimental analysis of the thermoreflectance response in the opposite case: an insulating layer on a conducting substrate. We show theoretically that conductivity and diffusivity can be determined independently thanks to a comparison with the substrate. The method is applied to experiments performed on a silicon substrate covered with a thin layer deposited by sputtering a titanium target.
Electromagnetic responses of magnetic conductive hollow fibers
Authors: Deng Lianwen , Luo Heng , Huang Shengxiang , Zhou Liang , Hu Zhaowen , Zhou Kesheng , Xiao Peng
Published: April 2012

Electromagnetic parameters for a magnetic conductive hallow fiber have been derived, and the anisotropy of the magnetic permeability and the electric permittivity for a hollow fiber was demonstrated theoretically. The axial parameters μ// and ɛ// are the key factors related to electromagnetic characteristics of the hollow fiber. Simulations have been carried out to study the axial permeability μ//, and axial permittivity ɛ// of a magnetic conductive hallow fiber with different geometric, and electrical parameters such as diameter, aspect ratio and conductivity The simulations carried out reveal several interesting properties of the hallow fiber’s electromagnetic parameters. (1) The parameters μ′//, μ″//, ɛ′// and ɛ″// all decrease with increasing outer radius from 0.5 to 6 µm. (2) When the aspect ratio of the hallow fiber is above 30 µm, μ′// and μ″// remain at constant, while, ɛ′// and ɛ″// are found to increase. (3) The parameters μ′//, μ″//, and ɛ′// all decrease with increasing conductivity, however ɛ″// increases with increasing conductivity. Additionally these simulated results are consistent with reported experimental results carried out on electromagnetically modified hollow carbon fibers.
Transient growth in Rayleigh-Bénard-Poiseuille/Couette convection
Authors: John Soundar Jerome J. , Chomaz Jean-Marc , Huerre Patrick
Published: April 2012

An investigation of the effect of a destabilizing cross-stream temperature gradient on the transient growth phenomenon of plane Poiseuille flow and plane Couette flow is presented. Only the streamwise-uniform and nearly streamwise-uniform disturbances are highly influenced by the Rayleigh number Ra and Prandtl number Pr. The maximum optimal transient growth Gmax of streamwise-uniform disturbances increases slowly with increasing Ra and decreasing Pr. For all Ra and Pr, at moderately large Reynolds numbers Re, the supremum of Gmax is always attained for streamwise-uniform perturbations (or nearly streamwise-uniform perturbations, in the case of plane Couette flow) which produce large streamwise streaks and Rayleigh-Bénard convection rolls (RB). The optimal growth curves retain the same large-Reynolds-number scaling as in pure shear flow. A 3D vector model of the governing equations demonstrates that the short-time behavior is governed by the classical lift-up mechanism and that the influence of Ra on this mechanism is secondary and negligible. The optimal input for the largest long-time response is given by the adjoint of the dominant eigenmode with respect to the energy scalar product: the RB eigenmode without its streamwise velocity component. These short-time and long-time responses depict, to leading order, the optimal transient growth G(t). At moderately large Ra (or small Pr at a fixed Ra), the dominant adjoint mode is a good approximation to the optimal initial condition for all time. Over a general class of norms that can be considered as growth functions, the results remain qualitatively similar, for example, the dominant adjoint eigenmode still approximates the maximum optimal response.
Characteristic free volume change of bulk metallic glasses
Authors: Hu Qiang , Zeng Xie-Rong , Fu M. W.
Published: April 2012

The free volume change ΔVf(T) of bulk metallic glasses (BMGs) relative to a hypothesized amorphous reference state was measured using the thermal dilatation method. The characteristic free volume change, i.e., the free volume released in structural relaxation ΔVf-sr, was identified quantitatively from the ΔVf(T) curve. For a Fe-based BMG, it was found that ΔVf-sr increases with decreases in the sample diameter and heating rate. ΔVf-sr measured under the same sample diameter and heating rate conditions allowed the convenient comparison of different BMGs. The comparison revealed that the glass-forming ability (GFA) enhancement of each of two Pd-, Mg-, Cu-, Zr-, Ti-, and Fe-based BMGs can be sensitively reflected in the decrease in ΔVf-sr and the narrowing of the difference between the peak temperature of the thermal expansion coefficient and the end temperature of the glass transition process. In addition, for these twelve typical BMGs, there is a good linear relationship between ΔVf-sr and LogDc2 or LogDc, where Dc is the critical diameter. ΔVf-sr is thus sensitive to and has a close correlation with GFA. Furthermore, the ΔVf-sr measurement results are in good agreement with the free volume change measured with the specific heat capacity, room temperature density, and positron annihilation lifetime methods. In the study of the relationship between the structure and properties of BMGs, ΔVf-sr thus plays an important role given its comparability and convenience.
Electrical properties of the amorphous interfacial layer between Al electrodes and epitaxial NiO films
Authors: Hyuck Jang Jae , Kwon Ji-Hwan , Ran Lee Seung , Char Kookrin , Kim Miyoung
Published: April 2012

The amorphous interfacial layer (a-IL) between Al electrode and epitaxial NiO films were studied using electron energy-loss spectroscopy (EELS) and energy-dispersive x-ray spectroscopy. Two distinct properties were found in the a-IL, i.e., a lower metallic and an upper insulating layer. EELS results revealed that the metallic Ni atoms were responsible for the conducting nature of the lower oxide amorphous layer. The resistance behavior of Al/a-IL/epi-NiO was changed from a high to a low resistance state after forming process. The resistance change could be explained by the formation of a nanocrystalline metal alloy in the insulating amorphous layer.
High-efficiency acousto-optical interaction in phoxonic nanobeam waveguide
Authors: Hsiao Fu-Li , Hsieh Cheng-Yi , Hsieh Hao-Yu , Chiu Chien-Chang
Published: April 2012

We demonstrate the simultaneous existence of slow photonic and phononic modes in phoxonic nanobeam. The phoxonic nanobeam is formed by arranging air semi-cylinders along lateral sides of a suspended silicon waveguide. Because of the slow group velocities, the acousto-optical interactions are dramatically enhanced. The efficiencies of interaction are strongly related to the polarizations of both slow photonic and phononic modes. Our proposed structure is a potential high-efficiency acousto-optical modulator with ultra-small footprint size. The operating optical wavelength is about 1550 nm, while the acoustic frequency is about 6.8 GHz.
Thermal stability of magnetoelectric sensors
Authors: Shen Ying , Gao Junqi , Wang Yaojin , Li Jiefang , Viehland Dwight
Published: April 2012

The effect of temperature on the equivalent magnetic noise floor of Metglas-Pb(Zr,Ti)O3 (PZT) laminate magnetoelectric (ME) sensors has been investigated in the temperature range of −50 °C to 50 °C. In detail, the parameters that control the noise floor of ME sensors, such as capacitance, tan δ, and ME charge coefficient, were characterized. The results show the noise floor was thermally stable around 30 pT/√Hz (f = 1 Hz) over the studied temperature range. To demonstrate the relative invariance of ME sensor at different temperatures over the range studied, a simulation based on a noise model was conducted, where the predicted and measured equivalent magnetic noise floors were found to well agree.
Impacts of image force on the Schottky barrier height at metal-carbon nanotube contacts
Authors: Zhang Gang , Shi Qing
Published: April 2012

By using first-principles calculations and classical image force model, we studied the image force induced Schottky barrier (SB) height reduction in carbon nanotube (CNT)-metal contact. A low dielectric constant leads to a stronger band bending and therefore strongly reduces the SB height. This reduction depends on carrier concentration and CNT diameter. For CNT with carrier concentration of 1020 cm−3, the reduction in SB height caused by image force is up to 0.7 eV when CNT diameter is less than 20 Å. Our results demonstrate that image force induced SB height reduction is important for the design of CNT-based nanoelectronic devices.
A permendur-piezoelectric multiferroic composite for low-noise ultrasensitive magnetic field sensors
Authors: Sreenivasulu G. , Laletin U. , Petrov V. M. , Petrov V. V. , Srinivasan G.
Published: April 2012

Low-frequency and resonance magnetoelectric (ME) effects have been studied for a trilayer of permendur (alloy of Fe-Co-V) and lead zirconate titanate (PZT). The high permeability and high magnetostriction for permendur, key ingredients for magnetic field confinement, and ME response result in ME voltage coefficient of 23 V/cm Oe at low-frequency and 250 V/cm Oe at electromechanical resonance (EMR) for a sample with PZT fibers and inter-digital-electrodes. Theoretical ME coefficients are in agreement with the data. Measured magnetic noise floor of 25 pT/√Hz at 1 Hz and 100 fT/√Hz at EMR are comparable to best values reported for Metglas-PZT fiber sensors.
The impact of active layer thickness on low-frequency noise characteristics in InZnO thin-film transistors with high mobility
Authors: Choi Hyun-Sik , Jeon Sanghun , Kim Hojung , Shin Jaikwang , Kim Changjung , Chung U-In
Published: April 2012

We investigated low-frequency noise (LFN) characteristics in passivated InZnO thin-film transistors with various active layer thicknesses. These LFNs are matched to the mobility fluctuation model [F. N. Hooge, IEEE Trans. Electron Devices 41, 1926 (1994)]. According to this model, the Hooge’s parameter (αH) is significantly increased as the active layer thickness is decreased. By plotting the αH with the effective mobility (μeff), we found that the αH is proportional to the μeff−1. This indicates that the mobility fluctuation by the impurity scattering is significantly increased as the active layer thickness is decreased, and that is the main origin of the LFN increments in the thinner active-layer-thickness devices.
Nanotube-based scanning rotational microscope
Authors: Popov Andrey M. , Lebedeva Irina V. , Knizhnik Andrey A.
Published: April 2012

A scheme of the scanning rotational microscope is designed. This scheme is based on using carbon nanotubes simultaneously as a probe tip and as a bolt/nut pair which converts translational displacements of two piezo actuators into pure rotation of the probe tip. First-principles calculations of the interaction energy between movable and rotational parts of the microscope confirm the capability for its operation. The scanning rotational microscope with a chemically functionalized nanotube-based tip can be used to study how the interaction between individual molecules or a molecule and a surface depends on their relative orientation.
A pulse-modulated nonequilibrium atmospheric-pressure microwave argon plasma discharge preionized by a kilohertz excited plasma jet
Authors: Li Shou-Zhe , Xu Mao-Chun , Zhang Xin , Zhang Jialiang
Published: April 2012

A pulse-modulated nonequilibrium atmospheric-pressure microwave argon surface wave plasma is generated by means of a preionization discharge with a single-electrode plasma jet driven by a power supply of 50 kHz. It is found that the electron induced Saha-like balance dominates excitation process in the plasma discharge through the electron temperature varying with the microwave input power and the applied voltage of kilohertz power supply. The microwave pulse-modulating effect on nonequilibrium characteristics of dual-frequency exciting argon surface wave plasma is studied by spectroscopic measurement of the excitation temperature and gas temperature.
Do as I Say, Not as I Do: The Affective Space of Family Life and the Generational Transmission of Drinking Cultures
Authors: Valentine Gill , Jayne Mark , Gould Myles
Published: April 2012

In the context of new modernity, intimacy, theorized in terms of families as the embodied practices which mediate relationships between parents and children across the life course, has been reconceptualized. As part of wider transformations in social relations wrought by the ideological extension of neoliberalism into the realm of social and affective relationships, the language and logic of the market in terms of the importance of individual autonomy and choice have infiltrated family practices, shifting many of the responsibilities and risks for maximizing the life chances of children from governments to families. This principle of parental responsibility for children's present and future well-being means that anxiety about doing the ‘right thing’ is at the centre of contemporary experiences of intimate family relationships. Yet how such attitudes are translated into everyday practices of knowing, loving, and caring for each other by parents and children within the affective space of the home has been relatively underrepresented in geographers' thinking about families. Drawing on a survey of 2089 parents/carers and case-study research with ten families with children aged 5–12 years old, the paper begins with an exploraiton of parents' perceptions of when, how, and where children ought to be introduced to alcohol (extrafamilial norms). It then focuses on lived realities by examining what practices parents model to their children through everyday family life. The conclusion reflects on how the social distance between adults and children is being reduced and the implications of the contemporary realities of everyday familial intimacy for wider processes of demoralization.
Comparison of two non-lethal methods for dietary studies in terrestrial salamanders
Authors: Crovetto Federico , Romano Antonio , Salvidio Sebastiano
Published: April 2012

Context Concerns about conservation and ethics in amphibian research have been raised recently; therefore, non-lethal methods should always be preferred to investigate food habits in wild populations. However, there are no studies that compared the data obtained by different non-lethal dietary methods in amphibians. Aims We compared the dietary habits obtained from stomach flushing, a method validated against stomach dissection, and faecal analysis on the same 31 individuals of the European plethodontid Speleomantes strinatii, a completely terrestrial salamander. Methods After being stomach-flushed in the field, salamanders were kept in the laboratory at constant humidity and temperature to obtain faecal samples. Analyses comprised diversity and niche overlap indexes, as well as permutation, repeated-measures tests and graphical methods. Key results Niche overlap between the two samples was low (Ojk = 0.58) and prey diversity was significantly (P = 0.001) higher in stomach contents. There were also differences in the abundance of fly larvae, springtails and ants and the interpretation of the population trophic strategy varied according to the sampling method used. Key conclusions Stomach flushing and faecal analysis gave different information, because, apparently, a differential prey degradation occurred. During the digestive process, ants became dominant, whereas springtails and fly larvae became under-represented in faecal samples. Therefore, on the basis of faecal analysis, diet diversity was underestimated and many individuals improperly appeared as ant-specialist feeders. Implications In terrestrial salamanders, results from stomach flushing and faecal analysis should not be compared among studies, populations or species. Moreover, stomach flushing should always be preferred when assessing the trophic strategy and the role in food webs of salamanders.
Use of a native predator for the control of an invasive amphibian
Authors: Louette Gerald
Published: April 2012

Context The control of invasive alien species is essential for securing native biodiversity. As for the American bullfrog, Lithobates catesbeianus (Shaw 1802), suspected to cause ecological damage around large parts of the globe, comprehensive management techniques are currently absent. Aims To fill this gap, opportunities arising from biomanipulation of permanent water bodies inhabited by fish were explored. Methods A multi-annual experiment was performed in small and shallow ponds, and effects of complete drawdown (with amphibian and fish removal) and predation (introduction of originally occurring native northern pike, Esox lucius) on non-indigenous bullfrogs were investigated. Key results The presence of pike lead to a strong decline in bullfrog tadpole numbers, whereas no effect of drawdown was observed. Also, communities receiving pike harboured substantially less small and mostly planktivorous fish species (e.g. pumpkinseed, Lepomis gibbosus, and topmouth gudgeon, Pseudorasbora parva). Conclusions The reduction in bullfrog tadpoles may be assigned to both direct and indirect effects induced by pike. First, direct pike predation on tadpoles was observed. Second, as the occurrence of macroinvertebrate-feeding pumpkinseed was low in the presence of pike, the indirect effect of predation by macroinvertebrates on tadpoles may significantly increase, leading to tadpole decline. Implications Biomanipulation of permanent water bodies inhabited by fish can thus be regarded as a candidate for effective and sustainable control of invasive bullfrog. Piscivorous fish introduction may be applied in the specific type of water body, but requires careful consideration of the indigenous status of the introduced species, angling purposes, or specific nature values.
Uncovering the secret lives of sewer rats (Rattus norvegicus): movements, distribution and population dynamics revealed by a capture - mark - recapture study
Authors: Heiberg Ann-Charlotte , Sluydts Vincent , Leirs Herwig
Published: April 2012

Context.
In many parts of the world, brown rats have colonised sewer systems and the rat populations in sewers are often thought to be a source of problems with rats on the surface. The management of sewer rat populations is usually performed with little, if any, knowledge of the dynamics and behaviour of these populations.

Aims.
The study aimed to uncover the population dynamics, movements and distribution of rats in populations living in sewers.

Methods.
We studied rats in a capture–mark–recapture study in two adjacent but separate sewer systems in suburban Copenhagen, Denmark, covering a surface area of 30 Ha. Multiple-capture live traps were placed in manholes in public sewers; animals were marked individually and data were collected every fourth week for a period of almost 3 years.

Key results.
In total, 332 individual rats were trapped. Approximately one-third were only caught once, half of these were juveniles. The median time an individual was present in the sewers was 4 months with maxima up to 22 months. Abundance ranged from 2 to 44 animals per sewer system and the dynamics showed no regular fluctuations. Rats were distributed throughout the study area, regardless of sewer dimensions. Juvenile rats were captured more in the smaller and drier sewer sections. Activity areas of rats of both sexes overlapped partially, and observations of bite wounds were rare, suggesting a high degree of tolerance. The average maximal distance covered by rats was ~200 m for both sexes. Day-to-day movements took place over shorter distances. There were no movements of rats between sewer systems and no sewer rats were observed to be active on the surface. The rat populations seemed to be substructured in smaller groups.

Conclusions.
Sewer rat populations vary irregularly in abundance. Pipe dimensions are not important for the presence of rats but breeding seems concentrated in smaller and drier pipes. Most individuals are resident and live in small groups that are active in a limited area only, but still there is a fair group of dispersing rats.

Implications.
Sewer rat management should be spread out spatially in a sewer system since most rats move over short areas only. Recolonisation by dispersing rats must be taken into account if sewer systems are connected. It is likely that targeting smaller and drier pipes will affect reproductive success.
Intersubjectivity in newspaper editorials
Authors: Thompson Geoff
Published: April 2012

In this article, I take a discoursal perspective on intersubjectivity, exploring ways in which intersubjective meanings may be realized across texts, and the kinds of effects that arise from the combination of different forms. In particular, I focus on how writers may exploit intersubjective choices to enact interaction with their intended audience. I carry out an illustrative analysis on a small corpus of editorials from two British newspapers, one quality and one popular; and I demonstrate that there is clear connections between the readership of the two newspapers as described on their audience demographic webpages and the ways in which the editorial writers deploy the resources of interactant reference, mood and modality to construe different kinds of audience.