bluuebunny/crossref_metadata_2025 huggingface dataset:
(Dis)advantages of student subjects: What is your research question?
Authors: Gächter Simon
Published: June 2010

I argue that the right choice of subject pool is intimately linked to the research question. At least within economics, students are often the perfect subject pool for answering some fundamental research questions. Student subject pools can provide an invaluable benchmark for investigating generalizability across different social groups or cultures.
WEIRD walking: Cross-cultural research on motor development
Authors: Karasik Lana B. , Adolph Karen E. , Tamis-LeMonda Catherine S. , Bornstein Marc H.
Published: June 2010

Motor development – traditionally studied in WEIRD populations – falls victim to assumptions of universality similar to other domains described by Henrich et al. However, cross-cultural research illustrates the extraordinary diversity that is normal in motor skill acquisition. Indeed, motor development provides an important domain for evaluating cultural challenges to a general behavioral science.
Responsible behavioral science generalizations and applications require much more than non-WEIRD samples
Authors: Konečni Vladimir J.
Published: June 2010

There are many methodological considerations – some intricately associated with the use of WEIRD samples – that adversely affect external validity as much as, or even more than, unrepresentative sampling does. Among suspect applications, especially worrisome is the incorporation of WEIRD-based findings regarding moral reasoning and retribution into normative expectations, such as might be held by international criminal tribunals in “cognitively distant” war-torn areas.
Explaining why experimental behavior varies across cultures: A missing step in “The weirdest people in the world?”
Authors: Machery Edouard
Published: June 2010

In this commentary, I argue that to properly assess the significance of the cross-cultural findings reviewed by Henrich et al., one needs to understand better the causes of the variation in performance in experimental tasks across cultures.
ODD (observation- and description-deprived) psychological research
Authors: Rai Tage S. , Fiske Alan
Published: June 2010

Most psychological research consists of experiments that put people in artificial situations that elicit unnatural behavior whose ecological validity is unknown. Without knowing the psychocultural meaning of experimental situations, we cannot interpret the responses of WEIRD people, let alone people in other cultures. Psychology, like other sciences, needs to be solidly rooted in naturalistic observation and description of people around the world. Theory should be inductively developed and tested against real-world behavior.
Philosophy and WEIRD intuition
Authors: Stich Stephen
Published: June 2010

From Plato to the present, philosophers have relied on intuitive judgments as evidence for or against philosophical theories. Most philosophers are WEIRD, highly educated, and male. The literature reviewed in the target article suggests that such people might have intuitions that differ from those of people in other groups. There is a growing body of evidence suggesting that they do.
A topological embedding of the lexicon for semantic distance computation
Authors: DAVIS N. , GIRAUD-CARRIER C. , JENSEN D.
Published: June 2010

We show how a quantitative context may be established for what is essentially qualitative in nature by topologically embedding a lexicon (here, WordNet) in a complete metric space. This novel transformation establishes a natural connection between the order relation in the lexicon (e.g., hyponymy) and the notion of distance in the metric space, giving rise to effective word-level and document-level lexical semantic distance measures. We provide a formal account of the topological transformation and demonstrate the value of our metrics on several experiments involving information retrieval and document clustering tasks.
WordICA—emergence of linguistic representations for words by independent component analysis
Authors: HONKELA TIMO , HYVÄRINEN AAPO , VÄYRYNEN JAAKKO J.
Published: June 2010

We explore the use of independent component analysis (ICA) for the automatic extraction of linguistic roles or features of words. The extraction is based on the unsupervised analysis of text corpora. We contrast ICA with singular value decomposition (SVD), widely used in statistical text analysis, in general, and specifically in latent semantic analysis (LSA). However, the representations found using the SVD analysis cannot easily be interpreted by humans. In contrast, ICA applied on word context data gives distinct features which reflect linguistic categories. In this paper, we provide justification for our approach called WordICA, present the WordICA method in detail, compare the obtained results with traditional linguistic categories and with the results achieved using an SVD-based method, and discuss the use of the method in practical natural language engineering solutions such as machine translation systems. As the WordICA method is based on unsupervised learning and thus provides a general means for efficient knowledge acquisition, we foresee that the approach has a clear potential for practical applications.
Interlingual annotation of parallel text corpora: a new framework for annotation and evaluation
Authors: DORR BONNIE J. , PASSONNEAU REBECCA J. , FARWELL DAVID , GREEN REBECCA , HABASH NIZAR , HELMREICH STEPHEN , HOVY EDUARD , LEVIN LORI , MILLER KEITH J. , MITAMURA TERUKO , RAMBOW OWEN , SIDDHARTHAN ADVAITH
Published: June 2010

This paper focuses on an important step in the creation of a system of meaning representation and the development of semantically annotated parallel corpora, for use in applications such as machine translation, question answering, text summarization, and information retrieval. The work described below constitutes the first effort of any kind to annotate multiple translations of foreign-language texts with interlingual content. Three levels of representation are introduced: deep syntactic dependencies (IL0), intermediate semantic representations (IL1), and a normalized representation that unifies conversives, nonliteral language, and paraphrase (IL2). The resulting annotated, multilingually induced, parallel corpora will be useful as an empirical basis for a wide range of research, including the development and evaluation of interlingual NLP systems and paraphrase-extraction systems as well as a host of other research and development efforts in theoretical and applied linguistics, foreign language pedagogy, translation studies, and other related disciplines.
THE ELASTICITY OF SUBSTITUTION AS AN ENGINE OF GROWTH
Authors: Palivos Theodore , Karagiannis Giannis
Published: June 2010

This paper characterizes the elasticity of factor substitution in one-sector convex growth models with a general production function. It shows that an elasticity of substitution that is asymptotically greater than unity is a sufficient (but not a necessary) condition for the existence of a lower bound on the marginal product of capital, which in turn can lead to unbounded endogenous growth. Hence, an elasticity of substitution that eventually becomes greater than unity can counteract the role of diminishing returns to capital. This renders factor substitution a powerful engine of growth.
THE TIMING OF TAX COLLECTIONS AND THE STRUCTURE OF “IRRELEVANCE” THEOREMS IN A CASH-IN-ADVANCE MODEL
Authors: Sargent Thomas J. , Smith Bruce D.
Published: June 2010

A standard timing protocol in a cash-in-advance model allows the government to elude the inflation tax. That matters. Altering the timing of tax collections to make the government hold cash overnight disables some classical propositions but enables others. The altered timing protocol loses a Ricardian proposition and also the proposition that open market operations, accompanied by tax adjustments needed to finance the change in interest on bonds due the public, are equivalent to pure units changes. The altered timing enables a Modigliani–Miller equivalence proposition that does not otherwise prevail.
MANAGING PLURALITY: THE POLITICS OF THE PERIPHERY IN EARLY COLD WAR SINGAPORE
Authors: Yew Leong
Published: June 2010

Mainstream histories of the Cold War have tended to reduce the events surrounding Southeast Asian decolonization and nationalism to the universal notions of ideological confrontation, bipolarity, and the global division between a capitalist and communist camp. This obscures how multiple entities – the former colonial powers, different classes and ethnic groups, and local elites of different ideological and political persuasion – come into contention as they negotiate for a place in postcolonial society. Thus this article examines the case of Singapore in the 1950s and 1960s and argues that these forms of contention provincialize experiences with nationalism, communalism, and communism and by so doing disconnect them from the dominant narratives of the Cold War. I examine various texts by British colonial officials, communist and non-communist political figures, and university students that show how British attempts at managing a decolonizing entity were offset by the local intelligentsia's ambivalence in coming to terms with nationalism and communism.
Editorial – Zomia and beyond
Authors: Michaud Jean
Published: June 2010

This editorial develops two themes. First, it discusses how historical and anthropological approaches can relate to each other, in the field of the highland margins of Asia and beyond. Second, it explores how we might further our understandings of the uplands of Asia by applying different terms such as ‘Haute-Asie’, the ‘Southeast Asian Massif’, the ‘Hindu Kush–Himalayan region’, the ‘Himalayan Massif’, and in particular ‘Zomia’, a neologism gaining popularity with the publication of James C. Scott’s latest book, The art of not being governed: an anarchist history of upland Southeast Asia.1 Through a discussion of the notion of Zomia, I will reconsider certain ‘truths’ regarding highland Asian studies. In the process, I seek to contribute to disembedding minority studies from the national straitjackets that have been imposed by academic research bounded by the historical, ideological, and political limits of the nation-state.
Borderlands and border narratives: a longitudinal study of challenges and opportunities for local traders shaped by the Sino-Vietnamese border
Authors: Turner Sarah
Published: June 2010

In this article I examine the relevance of utilizing a ‘Zomia-like’ approach to interpreting upland livelihoods in the China–Vietnam borderlands, rather than the more commonly employed nation-state lens. I explore the challenges and opportunities presented by the international borderline between the provinces of Yúnnán, southwest China, and Lào Cai, northern Vietnam, for local populations, namely ethnic minorities Kinh (lowland Vietnamese) and Han Chinese. Investigating the creation and solidification of this borderline and border space, I undertake a historical and contemporary analysis of cross-border trade networks. This focuses on two time periods in which global–local linkages have been especially important in directly shaping border negotiations: the French colonial period and the contemporary economic reform era. Present-day border narratives collected in both countries during ethnographic fieldwork with local traders managing important highland commodities shed light on the means by which the borderline and borderland spaces are continuing to shape both prospects and constraints.
Implementing DBT: selecting, training and supervising a team
Authors: Swales Michaela A.
Published: June 2010

NICE Clinical Guideline no. 78 recently identified Dialectical Behaviour Therapy (DBT) as an appropriate treatment approach for the effective treatment of suicidal behaviours in the context of borderline personality disorder. Uniquely among the cognitive behavioural therapies DBT is a team-based treatment. This paper focuses on the task of selecting and training a team before considering issues in the training and supervision of therapists learning this approach.
Summertime precipitation variability over Europe and its links to atmospheric dynamics and evaporation
Authors: Zveryaev Igor I. , Allan Richard P.
Published: June 2010

Gridded monthly precipitation data for 1979–2006 from the Global Precipitation Climatology Project are used to investigate interannual summer precipitation variability over Europe and its links to regional atmospheric circulation and evaporation. The first empirical orthogonal function (EOF) mode of European precipitation, explaining 17.2%–22.8% of its total variance, is stable during the summer season and is associated with the North Atlantic Oscillation. The spatial‐temporal structure of the second EOF mode is less stable and shows month‐to‐month variations during the summer season. This mode is linked to the Scandinavian teleconnection pattern. Analysis of links between leading EOF modes of regional precipitation and evaporation has revealed a significant link between precipitation and evaporation from the European land surface, thus, indicating an important role of the local processes in summertime precipitation variability over Europe. Weaker, but statistically significant links have been found for evaporation from the surface of the Mediterranean and Baltic Seas. Finally, in contrast to winter, no significant links have been revealed between European precipitation and evaporation in the North Atlantic during the summer season.
Interannual, seasonal, and diel variation in soil respiration relative to ecosystem respiration at a wetland to upland slope at Harvard Forest
Authors: Phillips Stephen C. , Varner Ruth K. , Frolking Steve , Munger J. William , Bubier Jill L. , Wofsy Steven C. , Crill Patrick M.
Published: June 2010

Soil carbon dioxide efflux (soil respiration, SR) was measured with eight autochambers at two locations along a wetland to upland slope at Harvard Forest over a 4 year period, 2003–2007. SR was consistently higher in the upland plots than at the wetland margin during the late summer/early fall. Seasonal and diel hystereses with respect to soil temperatures were of sufficient magnitude to prevent quantification of the influence of soil moisture, although apparent short‐term responses of SR to precipitation occurred. Calculations of annual cumulative SR illustrated a decreasing trend in SR over the 5 year period, which were correlated with decreasing springtime mean soil temperatures. Spring soil temperatures decreased despite rising air temperatures over the same period, possibly as an effect of earlier leaf expansion and shading. The synchronous decrease in spring soil temperatures and SR during regional warming of air temperatures may represent a negative feedback on a warming climate by reducing CO2 production from soils. SR reached a maximum later in the year than total ecosystem respiration (ER) measured at a nearby eddy covariance flux tower, and the seasonality of their temperature response patterns were roughly opposite. SR, particularly in the upland, exceeded ER in the late summer/early fall in each year, suggesting that areas of lower efflux such as the wetland may be significant in the flux tower footprint or that long‐term bias in either estimate may create a mismatch. Annual estimates of ER decreased over the same period and were highly correlated with SR.
Large‐scale traveling ionospheric disturbance observed by superDARN Hokkaido HF radar and GPS networks on 15 December 2006
Authors: Hayashi H. , Nishitani N. , Ogawa T. , Otsuka Y. , Tsugawa T. , Hosokawa K. , Saito A.
Published: June 2010

On 15 December 2006, during the main phase of a relatively large storm, Doppler velocity data from the Super Dual Aural Radar Network (SuperDARN) Hokkaido radar, together with total electron content (TEC) data from the GPS Earth Observation Network (GEONET), recorded daytime large‐scale traveling ionospheric disturbances (LSTIDs). We studied two disturbances propagating southward and one disturbance propagating northward between 0000 and 0600 UT on 15 December 2006. The former disturbances were LSTIDs typical of those reported in many previous studies, whereas the latter was confirmed as an LSTID propagating from the Southern into the Northern Hemisphere, reported in a few past studies. From comparisons of SuperDARN Hokkaido radar Doppler velocity and GEONET TEC, we found a positive correlation between downward ionospheric motion and increasing TEC. This relationship is consistent with results of model calculation. This is the first observation of LSTIDs ranging from high to low latitude combining simultaneous SuperDARN HF radar and GPS network observations.
Atmospheric airglow fluctuations due to a tsunami‐driven gravity wave disturbance
Authors: Hickey M. P. , Schubert G. , Walterscheid R. L.
Published: June 2010

A spectral full‐wave model is used to study the upward propagation of a gravity wave disturbance and its effect on atmospheric nightglow emissions. Gravity waves are generated by a surface displacement that mimics a tsunami having a maximum amplitude of 0.5 m, a characteristic horizontal wavelength of 400 km, and a horizontal phase speed of 200 m/s. The gravity wave disturbance can reach F region altitudes before significant viscous dissipation occurs. The response of the OH Meinel nightglow in the mesopause region (∼87 km altitude) produces relative brightness fluctuations, which are ∼1% of the mean for overhead viewing. The wave amplitudes grow as the wave disturbance propagates upward, which causes the thermospheric nightglow emission responses to be large. For overhead viewing, the brightness fluctuations are ∼50% and 43% of the mean for the OI 6300 Å and O 1356 Å emissions, respectively. The total electron content fluctuation is ∼33% of the mean for overhead viewing. For oblique viewing, the relative brightness fluctuations are slightly smaller than those obtained for overhead viewing. In spite of this, the thermospheric nightglow brightness fluctuations are large enough that oblique viewing could provide early warning of an approaching tsunami. Thus, the monitoring of thermospheric nightglow emissions may be a useful augmentation to other observational techniques of tsunami effects in the thermosphere/ionosphere system.
NO2 air afterglow and O and NO densities from Odin‐OSIRIS night and ACE‐FTS sunset observations in the Antarctic MLT region
Authors: Gattinger R. L. , McDade I. C. , Alfaro Suzán A. L. , Boone C. D. , Walker K. A. , Bernath P. F. , Evans W. F. J. , Degenstein D. A. , Yee J.‐H. , Sheese P. , Llewellyn E. J.
Published: June 2010

The continuum spectrum produced by the NO + O(+M) → NO2(+M) + hv chemiluminescent reaction has been detected in the upper mesospheric dark polar regions by Optical Spectrograph and Infra‐Red Imager System (OSIRIS) on the Odin spacecraft. For the sample period of 8–9 May 2005, Southern Hemisphere, limb radiance profiles of continuum spectra, resolved from OH airglow and auroral contamination, are inverted to obtain volume emission rate altitude profiles. The maximum observed differential brightness referred to zenith viewing is 1.2 × 107 photons cm−2 s−1 nm−1 at 580 nm with a measurement uncertainty 5 × 105 photons cm−2 s−1 nm−1, for an analysis range 80–101 km. Atomic oxygen densities [O] required by the analysis to derive NO densities [NO] are determined from OSIRIS O2(b1Σg+ − X3Σg−) 0‐0 band night airglow observations and from Atmospheric Chemistry Experiment‐Fourier Transform Spectrometer (ACE‐FTS) sunset ozone observations. The derived Southern Hemisphere [O] map that shows pronounced longitudinal variation, maximum of 7 × 1011 cm−3, considerably exceeding MSIS model values, and suggests significant dynamical influence. Combining the continuum observations and the derived [O], a hemispheric map of derived [NO] is assembled that also shows considerable spatial variation, maximum of 1.1 × 109 cm−3, measurement uncertainty of 3 × 107 cm−3. Comparing the two maps, the geographical distribution of [NO] differs considerably from that of [O]. From a qualitative comparison, the distribution of derived [NO] is similar to that in coordinated GUVI LBH1 auroral precipitation images. The OSIRIS‐derived [NO] agrees with the measured ACE‐FTS [NO] to within 1 × 108 cm−3. The estimated systematic uncertainty of the NO densities derived from OSIRIS observations is approximately 30%.
Observed and modeled controls on precipitation δ18O over Europe: From local temperature to the Northern Annular Mode
Authors: Field Robert D.
Published: June 2010

Stable isotopes of oxygen and hydrogen are important paleoclimate indicators and can be obtained from many different natural archives in Europe such as tree rings and speleothems. In this study, a comparison was made of controls on European precipitation δ18O between observations from the Global Network of Isotopes in Precipitation and from the NASA Goddard Institute for Space Studies ModelE general circulation model. In both observations and the general circulation model, the local temperature effect was identified and extended outside of Europe. This temperature control, in turn, was related to a North Atlantic Oscillation‐like dipole but with centers of action different than standard NAO definitions. An examination of midtropospheric circulation controls showed that European δ18O in fact reflects the hemisphere‐wide teleconnections associated with the Northern Annular Mode. Seasonal differences were found in the strength of all controls on δ18O, with the annual controls being the combination of strong winter and weak summer controls. The weaker temperature effect in summer is well‐known and has been universally attributed to the effects of continental moisture recycling, but the results of this study show that an additional factor is the reduced variability in summertime atmospheric circulation. The strong agreement between observed and modeled controls can help to improve interpretations of paleoclimatic archives of δ18O, particularly in terms of shifts in atmospheric circulation.
Sensitivities of zonal mean atmospheric circulation to SST warming in an aqua‐planet model
Authors: Chen Gang , Plumb R. Alan , Lu Jian
Published: June 2010

Sensitivities of tropospheric winds and stratospheric Brewer‐Dobson Circulation (BDC) to SST warming are explored in an aqua‐planet atmospheric general circulation model. The tropospheric zonal wind change is quite sensitive to the location and sign of the gradient of SST perturbations with respect to the climatological jet. For the experiments with low latitude warming, the Hadley cell is intensified in the deep tropics, yet the Hadley cell boundary contracts for narrow meridional extents of warming and expands for broad extents of warming, associated with changes in extratropical eddy‐driven winds. Despite the complex changes of tropospheric wave forcing, the strength of the BDC is increased for all the experiments with low latitude warming. For the experiments with high latitude warming, the strength of the BDC decreases only if the warming extending to the subtropics.
Calmodulin-dependent nuclear import of HMG-box family nuclear factors: importance of the role of SRY in sex reversal
Authors: Kaur Gurpreet , Delluc-Clavieres Aurelie , Poon Ivan K. H. , Forwood Jade K. , Glover Dominic J. , Jans David A.
Published: June 2010

The HMG (high-mobility group)-box-containing chromatin-remodelling factor SRY (sex-determining region on the Y chromosome) plays a key role in sex determination. Its role in the nucleus is critically dependent on two NLSs (nuclear localization signals) that flank its HMG domain: the C-terminally located ‘β-NLS’ that mediates nuclear transport through Impβ1 (importin β1) and the N-terminally located ‘CaM-NLS’ which is known to recognize the calcium-binding protein CaM (calmodulin). In the present study, we examined a number of missense mutations in the SRY CaM-NLS from human XY sex-reversed females for the first time, showing that they result in significantly reduced nuclear localization of GFP (green fluorescent protein)–SRY fusion proteins in transfected cells compared with wild-type. The CaM antagonist CDZ (calmidazolium chloride) was found to significantly reduce wild-type SRY nuclear accumulation, indicating dependence of SRY nuclear import on CaM. Intriguingly, the CaM-NLS mutants were all resistant to CDZ's effects, implying a loss of interaction with CaM, which was confirmed by direct binding experiments. CaM-binding/resultant nuclear accumulation was the only property of SRY found to be impaired by two of the CaM-NLS mutations, implying that inhibition of CaM-dependent nuclear import is the basis of sex reversal in these cases. Importantly, the CaM-NLS is conserved in other HMG-box-domain-containing proteins such as SOX-2, -9, -10 and HMGN1, all of which were found for the first time to rely on CaM for optimal nuclear localization. CaM-dependent nuclear translocation is thus a common mechanism for this family of important transcription factors.
NAD-malic enzymes of Arabidopsis thaliana display distinct kinetic mechanisms that support differences in physiological control
Authors: Tronconi Marcos A. , Gerrard Wheeler Mariel C. , Maurino Verónica G. , Drincovich María F. , Andreo Carlos S.
Published: June 2010

The Arabidopsis thaliana genome contains two genes encoding NAD-MEs [NAD-dependent malic enzymes; NAD-ME1 (TAIR accession number At4G13560) and NAD-ME2 (TAIR accession number At4G00570)]. The encoded proteins are localized to mitochondria and assemble as homo- and hetero- dimers in vitro and in vivo. In the present work, the kinetic mechanisms of NAD-ME1 and -ME2 homodimers and NAD-MEH (NAD-ME heterodimer) were studied as an approach to understand the contribution of these enzymes to plant physiology. Product-inhibition and substrate-analogue analyses indicated that NAD-ME2 follows a sequential ordered Bi-Ter mechanism, NAD being the leading substrate followed by L-malate. On the other hand, NAD-ME1 and NAD-MEH can bind both substrates randomly. However, NAD-ME1 shows a preferred route that involves the addition of NAD first. As a consequence of the kinetic mechanism, NAD-ME1 showed a partial inhibition by L-malate at low NAD concentrations. The analysis of a protein chimaeric for NAD-ME1 and -ME2 indicated that the first 176 amino acids are associated with the differences observed in the kinetic mechanisms of the enzymes. Furthermore, NAD-ME1, -ME2 and -MEH catalyse the reverse reaction (pyruvate reductive carboxylation) with very low catalytic activity, supporting the notion that these isoforms act only in L-malate oxidation in plant mitochondria. The different kinetic mechanism of each NAD-ME entity suggests that, for a metabolic condition in which the mitochondrial NAD level is low and the L-malate level is high, the activity of NAD-ME2 and/or -MEH would be preferred over that of NAD-ME1.
Enterprise-Wide Business-IT Engagement in An Empowered Business Environment: The Case of Fedex Express EMEA
Authors: Viaene Stijn , De Hertogh Steven
Published: June 2010

In 2003, Rob Carter, CIO of international express courier FedEx, launched the ‘Six by Six’ (6 × 6) IT transformation program: a major rationalization and centralization effort to improve FedEx's IT service delivery to its business partners. This teaching case deals with the 6 × 6 efforts made by the IT department for Europe, Middle East, Indian sub-continent and Africa (EMEA). The case focuses on two objectives of the 6 × 6 program: (a) creating a consistent IT environment and (b) increasing delivery bandwidth to the business. Historically, FedEx Express in EMEA had granted high levels of empowerment to local business and IT people. Moreover, FedEx had always supported a ‘can-do’ mentality In both business and IT people. Consequently, the IT department was expected to keep the enterprise systems architecture resilient and supportive of longer-term enterprise growth, while keeping the IT development pipeline aligned with the often unpredictable stream of requests from empowered business constituents. The story begins in 2007, when a new Vice President for IT was appointed for the region. Part A deals with the IT department's efforts to set up a central systems architecture and IT resource estimation review process. Part B deals with demand-side prioritization issues. The suggested teaching plan assumes that Part A is discussed before the students receive Part B. Instructors can use this case to introduce their students to a realistic view on the complex puzzle of establishing enterprise-wide business-IT engagement patterns through IT governance in an empowered and operations-focused business environment.
An analytical investigation on singularity of current distribution around a crack in a long cylindrical superconductor
Authors: Xue Feng , Zhou You-He
Published: June 2010

This paper presents an analytical investigation to display the distribution of critical current flow and trapped magnetic field around a through crack centrally located in a long cylindrical superconductor on the basis of the Bean model and the Kim model. After a simple conformal mapping is employed to the case of that the superconductor is fully penetrated, the current streamlines, the current density, and the trapped field around the crack in the superconductor without deformation are obtained. It is shown that the crack results in a long-range disturbance of J(r) on the scale much larger than the crack length 2a and a large stagnation region of magnetic flux near the crack except for the singularity of the critical current at the crack tip. Meanwhile, it is also found that the singularity feature is different from the conventional stress one at the crack tip in a deformable body.
Obtaining molecular orientation from second harmonic and sum frequency scattering experiments in water: Angular distribution and polarization dependence
Authors: de Beer Alex G. F. , Roke Sylvie
Published: June 2010

We present a method for determining molecular orientation from second-order nonlinear light scattering experiments. Our modeling shows that there is an optimal angular region, for which the scattering pattern is most sensitive to molecular orientation. We show that molecular orientation can be retrieved from measuring intensities at different polarization combinations, measuring the relative amplitudes of different vibrational modes of the same moiety and by analyzing the shape of the angular scattering pattern. We further show that for C2v and C3v point groups, the asymmetric stretch mode displays a higher sensitivity to molecular orientation than the corresponding symmetric mode. We have implemented the model in an interactive simulation program that may be found at http://www.mf.mpg.de/en/abteilungen/roke/simulation.html.
Linear and nonlinear quantum ion acoustic waves in a plasma with positive, negative ions and Fermi electron gas
Authors: Saeed-ur-Rehman
Published: June 2010

Linear and nonlinear propagations of quantum ion acoustic waves in positive, negative ions and electron plasma have been vetted via the dispersion relation and Korteweg–de Vries equation, where the ions are inertial and electrons are inertialess. The quantum mechanical effects arising due to the quantum diffraction and Fermi–Dirac statistics for this system are taken into account. The existence, as well as the type (compressive/rarefactive) of solitary wave propagating in the system, is strongly dependent on the numerical value of dimensionless quantum parameter He. It is observed that negative ion population and ion mass ratio have emphatic influence on the phase velocity of ion acoustic wave and the propagation of localized coherent solitary structures at quantum scale in the system.
Investigation and modeling of bubble-bubble interaction effect in homogeneous bubbly flows
Authors: Seo Jung Hee , Lele Sanjiva K. , Tryggvason Gretar
Published: June 2010

The effect of bubble-bubble interaction in homogeneous bubbly flow is investigated by direct numerical simulation and a bubbly mixture model for bubbly shock flows at void fraction 0.4%–13%. It is found that the bubble-bubble interaction effect is significant at void fraction higher than O(1)% and decreases the amplitude and wavelength of the macroscale oscillations in the dispersive shock structure. For the modeling of bubble-bubble interaction effect, the locally volume averaged Rayleigh–Plesset (LVARP) equation, which is an extended version of the original Rayleigh–Plesset equation, is proposed in the present study. The results of bubbly mixture model using LVARP agree well with the direct simulation results for bubbly shock flows at void fraction up to 13%. The bubble-bubble interaction in nonuniform bubbly flows is also investigated in bubbly flows with randomized initial bubble positions. It is found that the LVARP model predicts the ensemble averaged behavior with reasonable accuracy.
Effect of thermally induced perturbation in supersonic boundary layers
Authors: Yan Hong , Gaitonde Datta
Published: June 2010

This paper investigates the mechanism of steady and unsteady thermal perturbation (also denoted as thermal bump) in a Mach 1.5 flat plate boundary layer. A high-fidelity upwind-biased third-order Roe scheme is used with the compressive van Leer harmonic limiter on a suitably refined mesh. The study consists of two parts. In the first part, the effects of the steady and pulsed thermal bumps are explored. It is shown that the finite-span thermal bumps generate streamwise vortices. With steady heating, the disturbance decays downstream. However, when the thermal bump is pulsed, vortex shedding is observed and the streamwise vortical disturbance grows with downstream distance, consistent with linear stability analysis. The integrated disturbance energy indicates that streamwise kinetic disturbance energy growth dominates over those associated with other two velocity and thermodynamic components. The second part of this paper explores the physical consequences of the nonlinear dynamics between the vortices produced by the pulsed bump and the compressible boundary layer. The resulting three-dimensional flow distortion generates hairpin structures which are aligned in the streamwise direction, suggesting that the transition process bears some similarity to K-type breakdown. The arrangement of these vortices is connected to the low-speed streaks observed in the evolving boundary layer. The shape factor, velocity, and Reynolds stress profiles suggest that the perturbed flow shows initiation of transition to turbulence, but remains transitional at the end of the plate.
Dimerization-assisted energy transport in light-harvesting complexes
Authors: Yang S. , Xu D. Z. , Song Z. , Sun C. P.
Published: June 2010

We study the role of the dimer structure of light-harvesting complex II (LH2) in excitation transfer from the LH2 [without a reaction center (RC)] to the LH1 (surrounding the RC) or from the LH2 to another LH2. The excited and unexcited states of a bacteriochlorophyll (BChl) are modeled by a quasispin. In the framework of quantum open system theory, we represent the excitation transfer as the total leakage of the LH2 system and then calculate the transfer efficiency and average transfer time. For different initial states with various quantum superposition properties, we study how the dimerization of the B850 BChl ring can enhance the transfer efficiency and shorten the average transfer time.
Assessing the accuracy of approximate treatments of ion hydration based on primitive quasichemical theory
Authors: Roux Benoît , Yu Haibo
Published: June 2010

Quasichemical theory (QCT) provides a framework that can be used to partition the influence of the solvent surrounding an ion into near and distant contributions. Within QCT, the solvation properties of the ion are expressed as a sum of configurational integrals comprising only the ion and a small number of solvent molecules. QCT adopts a particularly simple form if it is assumed that the clusters undergo only small thermal fluctuations around a well-defined energy minimum and are affected exclusively in a mean-field sense by the surrounding bulk solvent. The fluctuations can then be integrated out via a simple vibrational analysis, leading to a closed-form expression for the solvation free energy of the ion. This constitutes the primitive form of quasichemical theory (pQCT), which is an approximate mathematical formulation aimed at reproducing the results from the full many-body configurational averages of statistical mechanics. While the results from pQCT from previous applications are reasonable, the accuracy of the approach has not been fully characterized and its range of validity remains unclear. Here, a direct test of pQCT for a set of ion models is carried out by comparing with the results of free energy simulations with explicit solvent. The influence of the distant surrounding bulk on the cluster comprising the ion and the nearest solvent molecule is treated both with a continuum dielectric approximation and with free energy perturbation molecular dynamics simulations with explicit solvent. The analysis shows that pQCT can provide an accurate framework in the case of a small cation such as Li+. However, the approximation encounters increasing difficulties when applied to larger cations such as Na+, and particularly for K+. This suggests that results from pQCT should be interpreted with caution when comparing ions of different sizes.
E-beam lithography for micro-/nanofabrication
Authors: Altissimo Matteo
Published: June 2010

Electron beam lithography (EBL) is one of the tools of choice for writing micro- and nanostructures on a wide variety of materials. This is largely due to the fact that modern EBL machines are capable of writing nanometer-sized structures on areas up to mm2. The aim of this contribution is to give technical and practical backgrounds in this extremely flexible nanofabrication technique.
Anomalous momentum and energy transfer rates for electrostatic ion-cyclotron turbulence in downward auroral-current regions of the Earth’s magnetosphere. III
Authors: Jasperse John R. , Basu Bamandas , Lund Eric J. , Grossbard Neil
Published: June 2010

Recently, a new multimoment fluid theory was developed for inhomogeneous, nonuniformly magnetized plasma in the guiding-center and gyrotropic approximation that includes the effect of electrostatic, turbulent, wave-particle interactions (see Jasperse et al. [Phys. Plasmas 13, 072903 (2006); Jasperse et al., Phys. Plasmas13, 112902 (2006)]). In the present paper, which is intended as a sequel, it is concluded from FAST satellite data that the electrostatic ion-cyclotron turbulence that appears is due to the operation of an electron, bump-on-tail-driven ion-cyclotron instability for downward currents in the long-range potential region of the Earth’s magnetosphere. Approximate closed-form expressions for the anomalous momentum and energy transfer rates for the ion-cyclotron turbulence are obtained. The turbulent, inhomogeneous, nonuniformly magnetized, multimoment fluid theory given above, in the limit of a turbulent, homogeneous, uniformly magnetized, quasisteady plasma, yields the well-known formula for the anomalous resistivity given by Gary and Paul [Phys. Rev. Lett. 26, 1097 (1971)] and Tange and Ichimaru [J. Phys. Soc. Jpn. 36, 1437 (1974)].
The self-consistent parallel electric field due to electrostatic ion-cyclotron turbulence in downward auroral-current regions of the Earth’s magnetosphere. IV
Authors: Jasperse John R. , Basu Bamandas , Lund Eric J. , Grossbard Neil
Published: June 2010

The physical processes that determine the self-consistent electric field (E∥) parallel to the magnetic field have been an unresolved problem in magnetospheric physics for over 40 years. Recently, a new multimoment fluid theory was developed for inhomogeneous, nonuniformly magnetized plasma in the guiding-center and gyrotropic approximation that includes the effect of electrostatic, turbulent, wave-particle interactions (see Jasperse et al. [Phys. Plasmas 13, 072903 (2006); Jasperse et al., Phys. Plasmas13, 112902 (2006)]). In the present paper and its companion paper [Jasperse et al., Phys. Plasmas 17, 062903 (2010)], which are intended as sequels to the earlier work, a fundamental model for downward, magnetic field-aligned (Birkeland) currents for quasisteady conditions is presented. The model includes the production of electrostatic ion-cyclotron turbulence in the long-range potential region by an electron, bump-on-tail-driven ion-cyclotron instability. Anomalous momentum transfer (anomalous resistivity) by itself is found to produce a very small contribution to E∥; however, the presence of electrostatic, ion-cyclotron turbulence has a very large effect on the altitude dependence of the entire quasisteady solution. Anomalous energy transfer (anomalous heating and cooling) modifies the density, drift, and temperature altitude profiles and hence the generalized parallel-pressure gradients and mirror forces in the electron and ion momentum-balance equations. As a result, |E∥| is enhanced by nearly a factor of 40 compared to its value when turbulence is absent. The space-averaged potential increase associated with the strong double layer at the bottom of the downward-current sheet is estimated using the FAST satellite data and the multimoment fluid theory.
Analysis of a narrowband terahertz signal generated by a unitravelling carrier photodiode coupled with a dual-mode semiconductor Fabry–Pérot laser
Authors: Latkowski Sylwester , Parra-Cetina Josué , Maldonado-Basilio Ramón , Landais Pascal , Ducournau Guillaume , Beck Alexandre , Peytavit Emilien , Akalin Tahsin , Lampin Jean-François
Published: June 2010

A narrowband terahertz signal generated by a unitravelling carrier photodiode (UTC-PD) interfaced with a dual-mode Fabry–Pérot laser diode is demonstrated. A beat tone corresponding to the free spectral range is generated on the UTC-PD, and radiated by a transverse-electromagnetic-horn antenna. A terahertz signal at a frequency of 372 GHz, featuring a linewidth of 17 MHz is recorded by a subharmonic mixer coupled to an electrical spectrum analyzer. All components involved in this experiment operate at room temperature. The linewidth and the frequency of the emitted terahertz wave are analyzed, along with their dependency on dc-bias conditions applied to laser diode.
Near-field recording technique for high-resolution fluorescent imaging
Authors: Moriguchi C. , Inami W. , Egami C. , Kawata Y. , Terakawa S. , Tsuchimori M. , Watanabe O.
Published: June 2010

We present near-field fluorescent imaging with high resolution using a near-field recording technique. In this technique, optical intensity distribution localized near specimens is recorded as the surface topographic distribution of a photosensitive film. Because the technique does not require the scanning probes for detecting light, it is possible to observe living biological specimens. Fluorescence imaging is one of important tools in investigations of cell structures and functions in biology. We combined near-field recording technique with fluorescence imaging and demonstrated the observations of fluorescent particles beyond the diffraction limit.
Enhancing outcoupling efficiency of indium-tin-oxide-free organic light-emitting diodes via nanostructured high index layers
Authors: Riedel Boris , Hauss Julian , Geyer Ulf , Guetlein Johanna , Lemmer Uli , Gerken Martina
Published: June 2010

We fabricated organic light-emitting diodes with one-dimensional Bragg gratings as light extraction elements for substrate and waveguide modes. A Ta2O5 layer was introduced to obtain a high refractive index contrast to the subsequent anode layer. As anode we employed a highly conductive polymer. Laser interference lithography and physical plasma etching were used to pattern gratings into the Ta2O5 layer with a lattice constant of 370 nm and various grating depths. Mainly attributed to the outcoupling of the substrate modes, the structured devices exhibit a luminous flux which is up to four times higher compared to the unstructured reference devices.
Tunable and rotatable polarization controller using photonic crystal fiber filled with liquid crystal
Authors: Wei Lei , Alkeskjold Thomas Tanggaard , Bjarklev Anders
Published: June 2010

We design and fabricate a compact tunable and rotatable polarization controller using liquid crystal photonic band gap fibers. The electrically and thermally induced phase shift in the Poincaré sphere and corresponding birefringence change are measured. The direction of the electric field is managed by connecting four electrodes in different electrode configurations, and the thermal tunability is controlled by on-chip heaters. According to the results, a quarter-wave plate and a half-wave plate working in the wavelength range of 1520–1600 nm are experimentally demonstrated.
Strong crystalline field at the Fe site and spin rotation in olivine LiNi0.99 F57e0.01 PO4 material by Mössbauer spectroscopy
Authors: Kim Woochul , Rhee Chan Hyuk , Kim Hyung Joon , Moon Seung Je , Kim Chul Sung
Published: June 2010

The crystal structure of LiNi0.99 F57e0.01 PO4 compound has been determined to be orthorhombic by Rietveld refinement method. Temperature dependence of magnetization M shows an anomalous antiferromagnetic behavior. A sudden change in both the magnitude of magnetic hyperfine field and its slope below 11 K suggests that magnetic phase transition related to the spin ordering takes place abruptly. From the result of Mössbauer measurement, it is shown that a strong electric crystalline field of octahedral symmetry including the contribution of spin-orbit coupling and magnetic hyperfine field by space-modulated spin structure is acted to the sites of Fe2+ ions simultaneously at low temperature.
IκBη, a nuclear IκB protein, positively regulates the NF-κB–mediated expression of proinflammatory cytokines
Authors: Yamauchi Shumpei , Ito Hiroaki , Miyajima Atsushi
Published: June 2010

NF-κB is a key mediator for inducible transcription of various proinflammatory genes in innate immune responses, and its activity is strictly regulated by several IκB proteins. Although signaling pathways leading from pattern recognition receptors to NF-κB's activation in the cytoplasm have been studied extensively, the detail regulatory mechanisms of NF-κB–mediated transcriptional activity in the nucleus still remain unclear. Here we describe a unique member of the nuclear IκB protein family, IκBη. In a gene expression analysis of dendritic cells, we found a unique gene encoding an uncharacterized protein with ankyrin repeats. As it was structurally related to the IκB family, the protein was named “IκBη” and further characterized in the innate immune response. IκBη was widely expressed in various tissues and predominantly located in the nucleus. Moreover, biochemical analysis showed that IκBη associated with the p50 subunit of NF-κB. Knockdown of IκBη by siRNA suppressed the transcription of a subset of NF-κB–mediated proinflammatory cytokines in LPS-stimulated and poly (I:C)-transfected macrophages. These results indicate that IκBη regulates the NF-κB–mediated transcription of a wide variety of proinflammatory genes, playing a crucial role in the regulation of innate immune responses.
Simple strategy for synthesis of optically active allylic alcohols and amines by using enantioselective organocatalysis
Authors: Jiang Hao , Holub Nicole , Anker Jørgensen Karl
Published: June 2010

A simple organocatalytic one-pot protocol for the construction of optically active allylic alcohols and amines using readily available reactants and catalyst is presented. The described reaction is enabled by an enantioselective enone epoxidation/aziridination-Wharton-reaction sequence affording two highly privileged and synthetically important classes of compounds in an easy and benign way. The advantages of the described sequence include easy generation of stereogenic allylic centers, also including quaternary stereocenters, with excellent enantio- and diastereomeric-control and high product diversity. Furthermore, using monosubstituted enones as substrates, having moderate enantiomeric excess, the one-pot reaction sequence proceeds with an enantioenrichment of the products and high diastereoselectivity was achieved.