bluuebunny/crossref_metadata_2025 huggingface dataset:
North China Famine Revisited: Unsung Native Relief in the Warlord Era, 1920–1921
Authors: FULLER PIERRE
Published: August 2012

This paper makes the case that in China's most severe food crisis of the first quarter of the twentieth century—the great north China famine of 1920–1921—considerable life-saving relief was generated by three largely-neglected segments of Chinese society: Buddhist and other native charity efforts working along parallel social channels to the better-publicized missionary and international relief groups; the Republic's much-maligned military establishment; and officials and residents of the stricken communities themselves who were operating largely ‘below the radar’ of the distant, mostly city-based chroniclers of the famine whose voices have been privileged in the later history-writing process. Despite the recent fall of the Qing and the beginnings of a fractured era of warring between provincial governors, this paper suggests that communities in the increasingly neglected periphery of 1920 north China were significantly more viable and attentive to social welfare needs than has been previously recognized.
A reconfigurable, tendon-based haptic interface for research into human-environment interactions
Authors: von Zitzewitz Joachim , Morger André , Rauter Georg , Marchal-Crespo Laura , Crivelli Francesco , Wyss Dario , Bruckmann Tobias , Riener Robert
Published: August 2012

Human reaction to external stimuli can be investigated in a comprehensive way by using a versatile virtual-reality setup involving multiple display technologies. It is apparent that versatility remains a main challenge when human reactions are examined through the use of haptic interfaces as the interfaces must be able to cope with the entire range of diverse movements and forces/torques a human subject produces. To address the versatility challenge, we have developed a large-scale reconfigurable tendon-based haptic interface which can be adapted to a large variety of task dynamics and is integrated into a Cave Automatic Virtual Environment (CAVE). To prove the versatility of the haptic interface, two tasks, incorporating once the force and once the velocity extrema of a human subject's extremities, were implemented: a simulator with 3-DOF highly dynamic force feedback and a 3-DOF setup optimized to perform dynamic movements. In addition, a 6-DOF platform capable of lifting a human subject off the ground was realized. For these three applications, a position controller was implemented, adapted to each task, and tested. In the controller tests with highly different, task-specific trajectories, the three robot configurations fulfilled the demands on the application-specific accuracy which illustrates and confirms the versatility of the developed haptic interface.
Sketch-based interfaces for modeling and users' needs: Redefining connections
Authors: Elsen Catherine , Demaret Jean-Noël , Yang Maria C. , Leclercq Pierre
Published: August 2012

The goal of this paper is to reexamine assumptions about sketch-based interfaces for modeling in the context of designers' needs and practices. Research questions examine (a) the type of sketch support and (b) the timing of support. Both concepts try to determine when, what, why and how to augment design processes in a way that is useful to designers. Two experiments (one in architecture and one in product design) based on ergonomics theory are conducted and intend to question some of these assumptions. The Port Zeeland experiment examines how 20 novices perceive and copy a blurred architectural sketch, which provides clues for a sketch interpretation system. The “Tragere” experiment studies how 12 professional product designers, some of whom are “idea generators” and others “idea pursuers,” perceive, recognize, and handle a design sketch. The results take a designer's point of view in assessing the timing and value of sketch assistance in product design. The quantitative data analysis provides rich clues about when, why and how product sketches should be supported. The paper explores the strategies developed by designers to perceive and recognize graphical content and discusses the generation of three-dimensional volumes, the univocity state between sketches and three-dimensional models, and the treatment of features in freehand sketches. The paper concludes with observations on the timing and value of support, as first integrated in NEMo, a tool for early stage architectural design, and then in PEPS3, an early stage framework for product design.
Computer-aided design versus sketching: An exploratory case study
Authors: Veisz David , Namouz Essam Z. , Joshi Shraddha , Summers Joshua D
Published: August 2012

This paper presents a preliminary comparison between the role of computer-aided design (CAD) and sketching in engineering through a case study of a senior design project and interviews with industry and academia. The design team consisted of four senior level mechanical engineering students each with less than 1 year of professional experience are observed while completing an industry sponsored mechanical engineering capstone design project across a 17 week semester. Factors investigated include what CAD tools are used, when in the design process they are implemented, the justification for their use from the students' perspectives, the actual knowledge gained from their use, the impact on the final designed artifact, and the contributions of any sketches generated. At each design step, comparisons are made between CAD and sketching. The students implemented CAD tools at the onset of the project, generally failing to realize gains in design efficiency or effectiveness in the early conceptual phases of the design process. As the design became more concrete, the team was able to recognize clear gains in both efficiency and effectiveness through the use of computer assisted design programs. This study is augmented by interviews with novice and experienced industry users and academic instructors to align the trends observed in the case study with industry practice and educational emphasis. A disconnect in the perceived capability of CAD tools was found between novice and experienced user groups. Opinions on the importance of sketching skills differed between novice educators and novice industry professionals, suggesting that there is a change of opinion as to the importance of sketching formed when recent graduates transition from academia to industry. The results suggest that there is a need to emphasize the importance of sketching and a deeper understanding as to the true utility of CAD tools at each stage of the design process.
Expression of mRNA encoding leukaemia inhibitory factor (LIF) and its receptor (LIFRβ) in buffalo preimplantation embryos produced in vitro: markers of successful embryo implantation
Authors: Eswari S. , Sai Kumar G. , Sharma G. Taru
Published: August 2012

The objective of this study was to evaluate the effect of supplementation of recombinant leukaemia inhibitory factor (LIF) in culture media on blastocyst development, total cell number and blastocyst hatching rates and the reverse transcription-polymerase chain reaction analysis of preimplantation buffalo embryos to determine whether they contain the LIF-encoding mRNA and its beta receptor (LIFRβ) genes in different stages of preimplantation buffalo embryos. Cumulus–oocyte complexes retrieved from slaughterhouse buffalo ovaries were matured in vitro and fertilized using frozen buffalo semen. After 18 h of co-incubation with sperm, the presumptive zygotes were cultured in modified synthetic oviductal fluid without (control) or with rhLIF (100 ng/ml). There was no significant difference in the overall cleavage rate up to morula stage however the development of blastocysts, hatching rate and total cell numbers were significantly higher in the LIF-treated group than control. Transcripts for LIFRβ were detected from immature, in vitro-matured oocytes and in the embryos up to blastocyst stage, while transcripts for the LIF were detected from 8–16-cell stage up to blastocyst, which indicated that embryo-derived LIF can act in an autocrine manner on differentiation process and blastocyst formation. This study indicated that the addition of LIF to the embryo culture medium improved development of blastocysts, functional (hatching) and morphological (number of cells) quality of the blastocysts produced in vitro. The stage-specific expression pattern of LIF and LIFRβ mRNA transcripts in buffalo embryos indicated that LIF might play an important role in the preimplantation development and subsequent implantation of buffalo embryos.
The Clinical Application of Mobile Technology to Disaster Medicine
Authors: Case Timothy , Morrison Cecily , Vuylsteke Alain
Published: August 2012

Mobile health care technology (mHealth) has the potential to improve communication and clinical information management in disasters. This study reviews the literature on health care and computing published in the past five years to determine the types and efficacy of mobile applications available to disaster medicine, along with lessons learned.

Five types of applications are identified: (1) disaster scene management; (2) remote monitoring of casualties; (3) medical image transmission (teleradiology); (4) decision support applications; and (5) field hospital information technology (IT) systems. Most projects have not yet reached the deployment stage, but evaluation exercises show that mHealth should allow faster processing and transport of patients, improved accuracy of triage and better monitoring of unattended patients at a disaster scene. Deployments of teleradiology and field hospital IT systems to disaster zones suggest that mHealth can improve resource allocation and patient care. The key problems include suitability of equipment for use in disaster zones and providing sufficient training to ensure staff familiarity with complex equipment. Future research should focus on providing unbiased observations of the use of mHealth in disaster medicine.

CaseT, MorrisonC, VuylstekeA. The clinical application of mobile technology to disaster medicine. Prehosp Disaster Med. 2012;27(5):1-9.
Psycho-Education and Group Cognitive-Behavioural Therapy for Clinical Perfectionism: A Case-Series Evaluation
Authors: Steele Anna L. , Waite Sue , Egan Sarah J. , Finnigan Janelle , Handley Alicia , Wade Tracey D.
Published: August 2012

Background: Research indicates that psycho-education and cognitive behavioural interventions can reduce perfectionism but to date no group treatments have been examined. Aims: The current study utilized a case series design to compare psycho-education materials and subsequent eight-week group cognitive behaviour therapy (CBT) to a baseline waitlist in an outpatient community psychiatry sample (n = 21). Method: Participants were assessed on five occasions: baseline, 4 weeks later (waitlist), 4 weeks after receiving psycho-education material, post-treatment (8 weeks after receiving the group intervention), and 3-month follow-up. Results: There was a main effect of time for perfectionism and negative affect from baseline to post-group (effect sizes ranging from 1.46 to 1.91) that were maintained at 3-month follow-up. Conclusions: These results suggested that group CBT for clinical perfectionism may be beneficial, but that psycho-education alone is not effective for reducing perfectionism or negative affect.
Stratified statistical models of North Atlantic basin‐wide and regional tropical cyclone counts
Authors: Kozar Michael E. , Mann Michael E. , Camargo Suzana J. , Kossin James P. , Evans Jenni L.
Published: August 2012

Using the historical Atlantic tropical cyclone record, this study examines the empirical relationships between climate state variables and Atlantic tropical cyclone counts. The state variables considered as predictors include indices of the El Niño/Southern Oscillation and Northern Atlantic Oscillation, and both “local” and “relative” measures of Main Development Region sea surface temperature. Other predictors considered include indices measuring the Atlantic Meridional Mode and the West African monsoon. Using all of the potential predictors in a forward stepwise Poisson regression, we examine the relationships between tropical cyclone counts and climate state variables. As a further extension on past studies, both basin‐wide named storm counts and cluster analysis time series representing distinct flavors of tropical cyclones, are modeled. A wide variety of cross validation metrics reveal that basin‐wide counts or sums over appropriately chosen clusters may be more skillfully modeled than the individual cluster series. Ultimately, the most skillful models typically share three predictors: indices for the main development region sea surface temperatures, the El Niño/Southern Oscillation, and the North Atlantic Oscillation.
Multiyear lidar observations of the descending nature of tropical cirrus clouds
Authors: Nair Anish Kumar M. , Rajeev K. , Mishra Manoj Kumar , Thampi Bijoy V. , Parameswaran K.
Published: August 2012

Sedimentation of ice particles from cirrus clouds is one of the main processes responsible for dehydration of the upper troposphere. Multiyear‐long‐duration lidar observations of tropical cirrus over Thiruvananthapuram (8.5°N, 77°E) show the descending nature of these clouds throughout the year, with a mean frequency of occurrence of ∼20%. Majority of these descending cirrus occur near the base of tropical tropopause layer (TTL), while their frequency of occurrence and vertical extent of descent near the cold point tropopause are considerably less. On average, vertical displacement of the top and base of cirrus is almost similar. The most probable vertical displacement of cirrus is 1.5 – 2.5 km with descent duration of 1–2 h. However, in >20% of the cases, the vertical displacement is >3 km and ∼40% of the descending cirrus layers last for 2–5 h. Around 95% of descending cirrus clouds have a settling speed <0.8 ms−1. On average, the percentage of clouds that are thickening or thinning by >300 m during descent are almost equal (∼23% each), while the thickening/thinning of the remaining 54% is <300 m. About 79% of these descending cirrus layers have cloud optical depth (COD) between 0.1 to 0.5. None of these clouds are of sub‐visual type (COD <0.03). For the typical range of vertical displacements and CODs observed in the present study, the descending of cirrus clouds are estimated to decrease the longwave cloud radiative forcing at top of the atmosphere by 1 to 12.9 Wm−2.
Characterization of the hydraulics at natural step crests in step‐pool streams via weir flow concepts
Authors: Dust David , Wohl Ellen
Published: August 2012

The hydraulics of step‐pool streams are characterized by rapidly varied flow at the step crest, a hydraulic jump, and gradually varied flow in the pool unit of the step‐pool sequence. The flow characteristics at the step crests act as the hydraulic control for the water surface profile within the upstream pool unit. Using both field and flume investigations, we demonstrate the use of weir flow concepts for assessing and categorizing the hydraulic characteristics of natural step‐crests in step‐pool streams. We categorize the results of our investigations in terms of the crest‐clast, planform, longitudinal, and instream wood geometries of the step crests. The broad‐crested weir equation can be expressed asQ = C* g0.5Wh3/2, where Q is the flowrate, C* is a dimensionless discharge coefficient, W is the crest width, g is the acceleration of gravity, and h is the upstream flow depth above the step crest. Although the flow over a natural step is generally more complex than for an engineered weir, the results of our investigations indicate that the C*‐value for simulated and natural steps increases linearly as a function of the upstream head (h), with C* values ranging from 0.15 to 0.97. As a result, the application of weir flow concepts to natural steps provides means for (1) indirectly estimating flow rates; (2) characterizing the hydraulics for individual steps; (3) defining external and/or internal boundary conditions at step crests for hydraulic model simulations of natural or restored step‐pool streams; and (4) estimating the upstream pressure force acting on step‐crest clasts.
Magnetospheric line radiation event observed simultaneously on board Cluster 1, Cluster 2 and DEMETER spacecraft
Authors: Němec F. , Santolík O. , Parrot M. , Pickett J. S.
Published: August 2012

We present a case study of a magnetospheric line radiation (MLR) event observed simultaneously by Cluster 1 and Cluster 2 during a perigee passage at a radial distance of about 4 REand, at the same time, by the low‐orbiting DEMETER satellite. This unique constellation enables us to analyze spatiotemporal variability of the phenomenon. Although the Cluster spacecraft are separated by as much as 0.7 L‐shells, the observed wave pattern is the same on both. The analysis of B to E ratios indicates a quasiparallel propagation, which suggests that the waves cross the geomagnetic equator over a significant range of L‐shells, at least 3.9–4.6. Simultaneous observations by the DEMETER satellite separated by about 1.8 hours in MLT from the Cluster spacecraft indicate a significant azimuthal extent of the source. The obtained results show that during the MLR event the same wave pattern is observed over a significant portion of the inner magnetosphere.
Strain accumulation across strike‐slip faults: Investigation of the influence of laterally varying lithospheric properties
Authors: Huang Wen‐Jeng , Johnson Kaj M.
Published: August 2012

We use boundary element methods to develop antiplane, strike‐slip earthquake cycle models consisting of faulting in an elastic plate with possibly different thickness and stiffness on either side of the fault overlying a linear, Maxwell viscoelastic substrate. We show that isolated plate models that neglect the coupling of the plate to the underlying substrate might significantly overpredict the asymmetry in deformation across the fault. We also show that flow in a low‐viscosity channel in the lower crust could significantly contribute to the asymmetry. Through a fully probabilistic scheme, we invert geodetic data across three strike‐slip fault systems for effective elastic thickness and elastic stiffness on both sides of the fault using geological and geophysical constraints. For the Renun segment of the Great Sumatra fault, inversion results show the elastic layer on the east side is stiffer than the west side but the effective elastic thicknesses are not resolvable. For the Carrizo segment of the San Andreas fault, the inversion results slightly favor a thicker elastic layer on the east side (∼2.2 times) but stiffer layer on west side (∼1.2 times); however, uniform effective elastic thickness and stiffness cannot be ruled out. For the Aksay segment of the Altyn Tagh fault in northern Tibet, inversion results show the effective elastic crust of the Tarim Basin must be stiffer and thicker than the effective elastic crust of the Tibetan Plateau to the south, but the viscosity of a hypothesized mid‐crustal Tibetan channel is not resolvable.
Modeling pathways of riverine nitrogen and phosphorus in the Baltic Sea
Authors: Radtke H. , Neumann T. , Voss M. , Fennel W.
Published: August 2012

A better understanding of the fate of nutrients entering the Baltic Sea ecosystem is an important issue with implications for environmental management. There are two sources of nitrogen and phosphorus: riverine input and atmospheric deposition. In the case of nitrogen, the fixation of dinitrogen by diazotrophic bacteria represents a third source. From an analysis of stable nitrogen isotope ratios it was suggested that most of the riverine nitrogen is sequestered in the coastal rim, specifically along the southern Baltic Sea coast with its coarse sediments, whereas nitrogen from fixation dominates the central basins. However, pathways of nutrients and timescales between the input of the nutrients and their arrival in different basins are difficult to obtain from direct measurements. To elucidate this problem, we use a source attribution technique in a three‐dimensional ecosystem model, ERGOM, to track nutrients originating from various rivers. An “age” variable is attributed to the marked elements to indicate their propagation speeds and residence times. In this paper, we specifically investigate the spreading of nitrogen and phosphorus from the riverine discharges of the Oder, Vistula, Neman and Daugava. We demonstrate which regions they are transported to and for how long they remain in the ecosystem. The model results show good agreement with source estimations from observedδ15N values in sediments. The model results suggest that 95% of nitrogen is lost by denitrification in sediments, after an average time of 1.4 years for riverine nitrogen. The residence time of riverine phosphorus is much longer and exceeds our simulated period of 35 years.
A fast direct matrix solver for surface integral equation methods for electromagnetic wave scattering from non‐penetrable targets
Authors: Wei Jian‐Gong , Peng Zhen , Lee Jin‐Fa
Published: August 2012

The implementation details of a fast direct solver is described herein for solving dense matrix equations from the application of surface integral equation methods for electromagnetic field scatterings from non‐penetrable targets. The proposed algorithm exploits the smoothness of the far field and computes a low rank decomposition of the off‐diagonal coupling blocks of the matrices through a set of skeletonization processes. Moreover, an artificial surface (the Huygens' surface) is introduced for each clustering group to efficiently account for the couplings between well‐separated groups. Furthermore, a recursive multilevel version of the algorithm is presented. Although asymptotically the algorithm would not alter the bleak outlook of the complexity of the worst case scenario,O(N3) for required CPU time where N denotes the number of unknowns, for electrically large electromagnetic (EM) problems; through numerical examples, we found that the proposed multilevel direct solver can scale as good as O(N1.3) in memory consumption and O(N1.8) in CPU time for moderate‐sized EM problems. Note that our conclusions are drawn based on a few sample examples that we have conducted and should not be taken as a true complexity analysis for general electrodynamic applications. However, for the fixed frequency (h‐refinement) scenario, where the discretization size decreases, the computational complexities observed agree well with the theoretical predictions. Namely, the algorithm exhibits O(N) and O(N1.5) complexities for memory consumption and CPU time, respectively.
To ban or not to ban?
Authors: Howard Heidi Carmen , Borry Pascal
Published: August 2012

Direct‐to‐consumer genetic tests remain popular with consumers in Europe and the USA. Clinical geneticists and genetic counsellors, however, favour banning certain tests that have serious consequences for public health policies and general health care.
A novel dual-fluorescence strategy for functionally validating microRNA targets in 3′ untranslated regions: regulation of the inward rectifier potassium channel Kir2.1 by miR-212
Authors: Goldoni Dana , Yarham Janet M. , McGahon Mary K. , O’Connor Anna , Guduric-Fuchs Jasenka , Edgar Kevin , McDonald Denise M. , Simpson David A. , Collins Anthony
Published: August 2012

Gene targeting by microRNAs is important in health and disease. We developed a functional assay for identifying microRNA targets and applied it to the K+ channel Kir2.1 [KCNJ2 (potassium inwardly-rectifying channel, subfamily J, member 2)] which is dysregulated in cardiac and vascular disorders. The 3′UTR (untranslated region) was inserted downstream of the mCherry red fluorescent protein coding sequence in a mammalian expression plasmid. MicroRNA sequences were inserted into the pSM30 expression vector which provides enhanced green fluorescent protein as an indicator of microRNA expression. HEK (human embryonic kidney)-293 cells were co-transfected with the mCherry-3′UTR plasmid and a pSM30-based plasmid with a microRNA insert. The principle of the assay is that functional targeting of the 3′UTR by the microRNA results in a decrease in the red/green fluorescence intensity ratio as determined by automated image analysis. The method was validated with miR-1, a known down-regulator of Kir2.1 expression, and was used to investigate the targeting of the Kir2.1 3′UTR by miR-212. The red/green ratio was lower in miR-212-expressing cells compared with the non-targeting controls, an effect that was attenuated by mutating the predicted target site. miR-212 also reduced inward rectifier current and Kir2.1 protein in HeLa cells. This novel assay has several advantages over traditional luciferase-based assays including larger sample size, amenability to time course studies and adaptability to high-throughput screening.
Antidepressants inhibit DNA methyltransferase 1 through reducing G9a levels
Authors: Zimmermann Nicole , Zschocke Jürgen , Perisic Tatjana , Yu Shuang , Holsboer Florian , Rein Theo
Published: August 2012

The discovery of epigenetic processes as possible pivotal regulatory mechanisms in psychiatric diseases raised the question of how psychoactive drugs may impact the epigenetic machinery. In the present study we set out to explore the specificity and the mode of action of the reported inhibitory effect of the TCA (tricyclic antidepressant) amitriptyline on DNMT (DNA methyltransferase) activity in primary astrocytes from the rat cortex. We found that the impact on DNMT was shared by another TCA, imipramine, and by paroxetine, but not by venlafaxine or the mood stabilizers carbamazepine and valproic acid. DNMT activity in subventricular neural stem cells was refractory to the action of ADs (antidepressants). Among the established DNMTs, ADs primarily targeted DNMT1. The reduction of enzymatic DNMT1 activity was neither due to reduced DNMT1 expression nor due to direct drug interference. We tested putative DNMT1-inhibitory mechanisms and discovered that a known stimulator of DNMT1, the histone methyltransferase G9a, exhibited decreased protein levels and interactions with DNMT1 upon AD exposure. Adding recombinant G9a completely reversed the AD repressive effect on DNMT1 function. In conclusion, the present study presents a model where distinct ADs affect DNMT1 activity via G9a with important repercussions for possible novel treatment regimes.
Targeted oxidation of Torpedo californica acetylcholinesterase by singlet oxygen: identification of N-formylkynurenine tryptophan derivatives within the active-site gorge of its complex with the photosensitizer Methylene Blue
Authors: Triquigneaux Mathilde M. , Ehrenshaft Marilyn , Roth Esther , Silman Israel , Ashani Yakov , Mason Ronald P. , Weiner Lev , Deterding Leesa J.
Published: August 2012

The principal role of AChE (acetylcholinesterase) is termination of impulse transmission at cholinergic synapses by rapid hydrolysis of the neurotransmitter acetylcholine. The active site of AChE is near the bottom of a long and narrow gorge lined with aromatic residues. It contains a CAS (catalytic ‘anionic’ subsite) and a second PAS (peripheral ‘anionic’ site), the gorge mouth, both of which bind acetylcholine via π-cation interactions, primarily with two conserved tryptophan residues. It was shown previously that generation of 1O2 by illumination of MB (Methylene Blue) causes irreversible inactivation of TcAChE (Torpedo californica AChE), and suggested that photo-oxidation of tryptophan residues might be responsible. In the present study, structural modification of the TcAChE tryptophan residues induced by MB-sensitized oxidation was investigated using anti-N-formylkynurenine antibodies and MS. From these analyses, we determined that N-formylkynurenine derivatives were specifically produced from Trp84 and Trp279, present at the CAS and PAS respectively. Peptides containing these two oxidized tryptophan residues were not detected when the competitive inhibitors, edrophonium and propidium (which should displace MB from the gorge) were present during illumination, in agreement with their efficient protection against the MB-induced photo-inactivation. Thus the bound MB elicited selective action of 1O2 on the tryptophan residues facing on to the water-filled active-site gorge. The findings of the present study thus demonstrate the localized action and high specificity of MB-sensitized photo-oxidation of TcAChE, as well as the value of this enzyme as a model system for studying the mechanism of action and specificity of photosensitizing agents.
A Critical Review of Cloud Computing: Researching Desires and Realities
Authors: Venters Will , Whitley Edgar A
Published: August 2012

Cloud computing has become central to current discussions about corporate Information technology. To assess the impact that cloud may have on enterprises, it is important to evaluate the claims made in the existing literature and critically review these claims against empirical evidence from the field. To this end, this paper provides a framework within which to locate existing and future research on cloud computing. This framework is structured around a series of technological and service ‘desires’, that is, characteristics of cloud that are important for cloud users. The existing literature on cloud computing is located within this framework and is supplemented with empirical evidence from interviews with cloud providers and cloud users that were undertaken between 2010 and 2012. The paper identifies a range of research questions that arise from the analysis.
Upgrades of the high resolution imaging x-ray crystal spectrometers on experimental advanced superconducting tokamak
Authors: Lu B. , Wang F. , Shi Y. , Bitter M. , Hill K. W. , Lee S. G. , Fu J. , Li Y. , Wan B.
Published: August 2012

Two imaging x-ray crystal spectrometers, the so-called “poloidal” and “tangential” spectrometers, were recently implemented on experimental advanced superconducting tokamak (EAST) to provide spatially and temporally resolved impurity ion temperature (Ti), electron temperature (Te) and rotation velocity profiles. They are derived from Doppler width of W line for Ti, the intensity ratio of Li-like satellites to W line for Te, and Doppler shift of W line for rotation. Each spectrometer originally consisted of a spherically curved crystal and a two-dimensional multi-wire proportional counter (MWPC) detector. Both spectrometers have now been upgraded. The layout of the tangential spectrometer was modified, since it had to be moved to a different port, and the spectrometer was equipped with two high count rate Pilatus detectors (Model 100 K) to overcome the count rate limitation of the MWPC and to improve its time resolution. The poloidal spectrometer was equipped with two spherically bent crystals to record the spectra of He-like and H-like argon simultaneously and side by side on the original MWPC. These upgrades are described, and new results from the latest EAST experimental campaign are presented.
Variational properties of the discrete variable representation: Discrete variable representation via effective operators
Authors: Szalay Viktor , Ádám Péter
Published: August 2012

A variational finite basis representation/discrete variable representation (FBR/DVR) Hamiltonian operator has been introduced. By calculating its matrix elements exactly one obtains, depending on the choice of the basis set, either a variational FBR or a variational DVR. The domain of grid points on which the FBR/DVR is variational has been shown to consist of the subsets of the set of grid points one obtains by diagonalizing commuting variational basis representations of the coordinate operators. The variational property implies that the optimal of the subsets of a fixed number of points, i.e., the subset which gives the possible highest accuracy eigenpairs, gives the DVR of the smallest trace. The symmetry properties of the variational FBR/DVR Hamiltonian operator are analyzed and methods to incorporate symmetry into FBR/DVR calculations are discussed. It is shown how the Fourier-basis FBR/DVR suitable to solving periodic systems arise within the theory presented. Numerical examples are given to illustrate the theoretical results. The use of variational effective Hamiltonian and coordinate operators has been instrumental in this study. They have been introduced in a novel way by exploiting quasi-Hermiticity.
Hydrogen confined in single-wall carbon nanotubes: Anisotropy effects on ro-vibrational quantum levels
Authors: Suarez J. , Huarte-Larrañaga F.
Published: August 2012

The energy levels of a hydrogen molecule embedded in the cavity of single-walled carbon nanotubes with different morphologies are studied using quantum dynamics simulations. All degrees of freedom of the confined molecule are explicitly included in our model, revealing that the vibrational motion is notably affected by the presence of a confining potential. The most relevant effects are nevertheless found in the rotational motion of the molecule and the appearance of a quantized translational motion. We further analyze the dependence of the confinement effects on the interaction potential, considering different parameters for the carbon–hydrogen interaction.
Melting and dissociation of ammonia at high pressure and high temperature
Authors: Ojwang J. G. O. , Stewart McWilliams R. , Ke Xuezhi , Goncharov Alexander F.
Published: August 2012

Raman spectroscopy and synchrotron x-ray diffraction measurements of ammonia (NH3) in laser-heated diamond anvil cells, at pressures up to 60 GPa and temperatures up to 2500 K, reveal that the melting line exhibits a maximum near 37 GPa and intermolecular proton fluctuations substantially increase in the fluid with pressure. We find that NH3 is chemically unstable at high pressures, partially dissociating into N2 and H2. Ab initio calculations performed in this work show that this process is thermodynamically driven. The chemical reactivity dramatically increases at high temperature (in the fluid phase at T > 1700 K) almost independent of pressure. Quenched from these high temperature conditions, NH3 exhibits structural differences from known solid phases. We argue that chemical reactivity of NH3 competes with the theoretically predicted dynamic dissociation and ionization.
Computational study of hydrogen-bonded complexes of HOCO with acids: HOCO⋯HCOOH, HOCO⋯H2SO4, and HOCO⋯H2CO3
Authors: Hazra Montu K. , Francisco Joseph S. , Sinha Amitabha
Published: August 2012

Quantum chemistry calculations at the density functional theory (DFT) (B3LYP), MP2, QCISD, QCISD(T), and CCSD(T) levels in conjunction with 6-311++G(2d,2p) and 6-311++G(2df,2p) basis sets have been performed to explore the binding energies of open-shell hydrogen bonded complexes formed between the HOCO radical (both cis-HOCO and trans-HOCO) and trans-HCOOH (formic acid), H2SO4 (sulfuric acid), and cis-cis-H2CO3 (carbonic acid). Calculations at the CCSD(T)/6-311++G(2df,2p) level predict that these open-shell complexes have relatively large binding energies ranging between 9.4 to 13.5 kcal/mol and that cis-HOCO (cH) binds more strongly compared to trans-HOCO in these complexes. The zero-point-energy-corrected binding strengths of the cH⋯Acid complexes are comparable to that of the formic acid homodimer complex (∼13–14 kcal/mol). Infrared fundamental frequencies and intensities of the complexes are computed within the harmonic approximation. Infrared spectroscopy is suggested as a potential useful tool for detection of these HOCO⋯Acid complexes in the laboratory as well as in various planetary atmospheres since complex formation is found to induce large frequency shifts and intensity enhancement of the H-bonded OH stretching fundamental relative to that of the corresponding parent monomers. Finally, the ability of an acid molecule such as formic acid to catalyze the inter-conversion between the cis- and trans-HOCO isomers in the gas phase is also discussed.
Probing the mobility of supercooled liquid 3-methylpentane at temperatures near the glass transition using rare gas permeation
Authors: Matthiesen Jesper , Scott Smith R. , Kay Bruce D.
Published: August 2012

We study the diffusivity of three-methylpentane (3MP) using the permeation of inert gases (Ar, Kr, Xe) through the supercooled liquid created when initially amorphous overlayers are heated above Tg. We find that the permeation rates for all of the gases have non‑Arrhenius temperature dependences that are well described by the Vogel-Fulcher-Tamman equation. Comparison with the literature viscosity shows that the Stokes-Einstein equation breaks down at temperatures approaching Tg. The fractional Stokes-Einstein equation, D ∝ (T/η)n, does fit the permeation data, albeit with different values of n for each gas. There is qualitative agreement with the Stokes‑Einstein equation in that the permeation rate decreases with increasing radius of the rare gas probe, but the small differences in radii significantly underestimate the observed differences in the permeation rates. Instead the permeation rates are better correlated with the rare gas-3MP interaction energy than with the atomic radius.
Large-eddy simulation of turbulent channel flow using explicit filtering and dynamic mixed models
Authors: Singh Satbir , You Donghyun , Bose Sanjeeb T.
Published: August 2012

Large-eddy simulations of turbulent channel flow at Reτ = 395 are performed using explicit filtering. Two different subfilter-scale models, the dynamic Smagorinsky mixed model and the dynamic global-coefficient mixed model, are formulated in accordance with the explicitly filtered governing equations. The use of explicit filtering separates the filtering operation from discretization, thereby producing a grid-independent solution. In explicit-filter large-eddy simulations, both the dynamic Smagorinsky mixed and the dynamic global-coefficient mixed subfilter-scale models are found to produce solutions close to the non-filtered direct numerical simulation data when explicit-filter widths in the streamwise and spanwise directions and at the center of the channel in the wall normal direction are about four times the grid spacings for direct numerical simulation. Solutions obtained using explicit-filter large-eddy simulation are compared with solutions obtained using implicit-filter large-eddy simulation in a range of filter and grid resolution. Explicit-filter large-eddy simulations performed on gradually refined grids with a fixed set of explicit-filter widths are found to produce grid-converged solutions for both models. Similarly in implicit-filter large-eddy simulation, predictive capabilities of subfilter-scale models in explicit-filter large-eddy simulation are found to be interfered with truncation errors when the ratio of the explicit-filter width to the grid spacing is small.
Resonant splitting in periodic T-shaped photonic waveguides
Authors: Yin Wenjin , Yang Kaike , Xie Yuee , Ouyang Tao , Lau Leo , Chen Yuanping
Published: August 2012

Resonant splitting phenomena of photons in periodic T-shaped waveguide structure are investigated by the Green’s function method. An interesting resonant phenomenon is found in the transmission spectra. When the T-shaped structure contains n constrictions, there are (n − 1)-fold resonant splitting peaks in the low frequency region. The peaks are induced by low quasi-bound states in which photons are intensively localized in the stubs, while (n − 2)-fold resonant splitting occurs in the high frequency region. These peaks are induced by the high quasi-bound states where the photons are mainly localized in constrictions rather than in stubs. To this kind of quasi-bound state, the stub acts as a potential barrier rather than a well, which is the inverse of the case of the low quasi-bound states corresponding to the (n − 1)-fold splitting peaks. These resonant peaks can be modulated by adjusting the periodic number and geometry of the waveguide structures. The results can be used to develop optical switching devices, tunable filters, and coupled waveguides.
The bulk generation-recombination processes and the carrier lifetime in mid-wave infrared and long-wave infrared liquid nitrogen cooled HgCdTe alloys
Authors: Jóźwikowski K. , Kopytko M. , Rogalski A.
Published: August 2012

Comprehensive study of the bulk generation-recombination mechanisms and the carrier lifetime in long wavelength and mid wavelength infrared indium-doped as well as arsenic- and mercury vacancies-doped HgCdTe ternary alloys at liquid nitrogen temperature has been done. The excess minority carrier lifetime in HgCdTe materials has been calculated by solving the set of non-linear transport equations under conditions of small deviation from equilibrium. The results of numerical calculations of the carrier lifetime determined by the Auger 1, Auger 7, and Shockley-Read-Hall mechanisms related to mercury vacancies have been compared with experimental data available in the literature. We re-examine the carrier lifetime, including the impact of the electrical screening on Coulomb interaction of carriers in the Auger process to explain certain inconsistency between theoretical prediction and experimental data especially in highly doped p-type HgCdTe material. Moreover, the marginal significance of the interband radiative recombination has been indicated.
Electric-field-control of magnetic anisotropy of Co0.6Fe0.2B0.2/oxide stacks using reduced voltage
Authors: Kita Koji , Abraham David W. , Gajek Martin J. , Worledge D. C.
Published: August 2012

We have demonstrated purely electrical manipulation of the magnetic anisotropy of a Co0.6Fe0.2B0.2 film by applying only 8 V across the CoFeB/oxide stack. A clear transition from in-plane to perpendicular anisotropy was observed. The quantitative relationship between interface anisotropy energy and the applied electric-field was determined from the linear voltage dependence of the saturation field. By comparing the dielectric stacks of MgO/Al2O3 and MgO/HfO2/Al2O3, enhanced voltage control was also demonstrated, due to the higher dielectric constant of the HfO2. These results suggest the feasibility of purely electrical control of magnetization with small voltage bias for spintronics applications.
Terahertz transmission characteristics across the phase transition in VO2 films deposited on Si, sapphire, and SiO2 substrates
Authors: Shi Qiwu , Huang Wanxia , Wu Jing , Zhang Yaxin , Xu Yuanjie , Zhang Yang , Qiao Shen , Yan Jiazhen
Published: August 2012

Vanadium dioxide (VO2) films were deposited on high-purity Si, sapphire, and SiO2 substrates by an organic sol-gel method. The effect of the substrate on the structure, morphology, and phase transition properties of the VO2 films was demonstrated. We proposed that the film-substrate interaction induced the differences in the fraction of the +4 valence state vanadium oxide phase, surface morphology, and grain size for the VO2 films. The VO2 film on the Si substrate exhibited a switching property of about 2 orders of change in electrical resistivity. By contrast, the VO2 films on the sapphire and SiO2 substrates exhibited a switching property of about 3 orders of change in resistivity. The THz transmission across the phase transition in the VO2 films was quite different in the transmission modulation ratio, the width, and the slope of the hysteresis loop. In particular, the VO2 films on the sapphire and SiO2 substrates have the same reduction in THz transmission by about 46% comparing with about 35% in the VO2 film on the Si substrate. Furthermore, the VO2 film on the SiO2 substrate exhibits the widest hysteresis loop with the steepest slope.
Demonstration of a single-photon router with a cavity electromechanical system
Authors: Jiang Cheng , Chen Bin , Zhu Ka-Di
Published: August 2012

We demonstrate theoretically a scheme for realizing a single-photon router in a cavity electromechanical system. When a weak probe field is tuned on resonance with the microwave cavity, we can use a strong control field to choose to what output port of this probe field is delivered, which is based on the analogue of electromagnetically induced transparency effect in this coupled system. Routing between the reflection output port and the transmission output port can be achieved by turning off and on the control field. The router proposed here opens a good perspective for its applications in photonic quantum information networks.
Formation mechanism, optical and magneto-dielectric studies of new cubic spinel MgMnO3
Authors: Thota S. , Singh K. , Prasad B. , Kumar J. , Simon Ch. , Prellier W.
Published: August 2012

The formation mechanism, phase stability, optical and magnetodielectric properties of new cubic MgMnO3 bulk and nano-crystals are reported. The diffuse reflectance spectroscopy of this compound shows a ligand-to-metal charge transfer transition p[O2−]→eg[Mg2+] at 4 eV and the lowest spin allowed metal-to-metal transition at 2.43 eV. In bulk MgMnO3 with the defect cubic structure [Mg2+][Mg2+1/3Mn4+4/3□1/3]O4 (Seehra et al.Appl. Phys. Lett.97, 112507 (2010)10.1063/1.3489094) a clear change in the dielectric constant (ɛ′) is observed on cooling through its blocking temperature TB ∼17.5 K. This dielectric anomaly is magnetic field independent even at 14 kOe. A clear evidence of the magneto-dielectric effect is observed for T < TB. Possible origin of the magneto-dielectric coupling has been discussed.
Gas Price Variations and Urban Sprawl: An Empirical Analysis of the Twelve Largest Canadian Metropolitan Areas
Authors: Tanguay Georges A , Gingras Ian
Published: August 2012

We conduct a multivariate analysis of the potential impact of higher gas prices on urban sprawl in the twelve largest Canadian Metropolitan Areas for the period 1986–2006. Controlling for variables such as income and population, we show that higher gasoline prices have significantly reduced urban sprawl. On average, a 1% increase in gas prices has caused a 0.32% increase in the population living in the inner city and a 0.60% decrease in low-density housing units. Our results also show that higher incomes have played a significant role in increasing urban sprawl.
The Queer Time of Creative Urbanism: Family, Futurity, and Global City Singapore
Authors: Oswin Natalie
Published: August 2012

Singapore's rise as a ‘global city’ has attracted much scholarly attention, especially as its government has recently turned to ‘creative city’ strategies. In line with critiques made of other global and creative cities around the world, important critiques have been leveled that the city-state's developmental efforts are bureaucratic, hierarchical, narrowly economistic, and, most importantly, socially polarizing. This paper demonstrates that Singapore's global/creative city project is also heteronormative and, further, that this heteronormative logic is tied in fundamental ways to broad forms of social polarization. The drive to attract ‘foreign talent’ to the city-state as a key prong in attaining future economic growth has resulted in significant changes in sexual citizenship over the last decade. Efforts to shake off an authoritarian image and foster a creative economy have led to the liberalization of the government's approach to public expressions of homosexuality. Yet discriminatory legislation and policy that excludes gays and lesbians from full citizenship has been maintained. Further, Singapore maintains a bifurcated migration regime that invites ‘foreign talent’ and their families to become part of the national family through naturalization, while ‘foreign workers’ have no route to future citizenship and are prohibited from bringing dependents with them, as well as from marrying and/or having children locally. Through a coercive politics of constrained im/mobility, this alien surplus labour force is set on an alternative developmental path that precludes intimacy, love, and familial connection. Building on recent work on the notion of ‘queer time’, this paper calls attention to the ways in which the city-state's developmental aims are underpinned by an exclusionary notion of reproductive futurity, and argues that a queer theoretical approach adds much to critical efforts to undermine the Singapore government's illiberal politics of pragmatism.