bluuebunny/crossref_metadata_2025 huggingface dataset:
Persulfide formation on mitochondrial cysteine desulfurase: enzyme activation by a eukaryote-specific interacting protein and Fe–S cluster synthesis
Authors: Pandey Alok , Golla Ramesh , Yoon Heeyong , Dancis Andrew , Pain Debkumar
Published: August 2012

Cysteine desulfurases abstract sulfur from the substrate cysteine, generate a covalent persulfide on the active site cysteine of the enzyme, and then donate the persulfide sulfur to various recipients such as Fe–S clusters. In Saccharomyces cerevisiae, the Nfs1p protein is the only known cysteine desulfurase, and it forms a complex with Isd11p (Nfs1p·Isd11p). Both of these proteins are found primarily in mitochondria and both are essential for cell viability. In the present study we show, using the results of experiments with isolated mitochondria and purified proteins, that Isd11p is required for the cysteine desulfurase activity of Nfs1p. Whereas Nfs1p by itself was inactive, the Nfs1p·Isd11p complex formed persulfide and was active as a cysteine desulfurase. In the absence of Isd11p, Nfs1p was able to bind the substrate cysteine but failed to form a persulfide. Addition of Isd11p allowed Nfs1p with bound substrate to generate a covalent persulfide. We suggest that Isd11p induces an activating conformational change in Nfs1p to bring the bound substrate and the active site cysteine in proximity for persulfide formation. Thus mitochondrial Nfs1p is different from bacterial cysteine desulfurases that are active in the absence of accessory proteins. Isd11p may serve to regulate cysteine desulfurase activity in mitochondria.
Slightly two- or three-dimensional self-similar solutions
Authors: Sari Re'em , Bode Nate , Yalinewich Almog , MacFadyen Andrew
Published: August 2012

Self-similarity allows for analytic or semi-analytic solutions to many hydrodynamics problems. Most of these solutions are one-dimensional. Using linear perturbation theory, expanded around such a one-dimensional solution, we find self-similar hydrodynamic solutions that are two- or three-dimensional. Since the deviation from a one-dimensional solution is small, we call these slightly two-dimensional and slightly three-dimensional self-similar solutions, respectively. As an example, we treat strong spherical explosions of the second type. A strong explosion propagates into an ideal gas with negligible temperature and density profile of the form ρ(r, θ, ϕ) = r−ω[1 + σF(θ, ϕ)], where ω > 3 and σ ≪ 1. Analytical solutions are obtained by expanding the arbitrary function F(θ, ϕ) in spherical harmonics. We compare our results with two-dimensional numerical simulations, and find good agreement.
Photoelectron spectroscopic study of the E ⊗ e Jahn-Teller effect in the presence of a tunable spin-orbit interaction. III. Two-state excitonic model accounting for observed trends in the $\tilde{\rm X}^{\,2}{\rm {E}}$X̃2E ground state of $\rm {CH}_3\rm {X}^+\,(\rm {X}=\rm {F,\,Cl,\,Br,\,I})$ CH 3X+(X=F, Cl , Br ,I) and $\rm {CH}_3\rm {Y}\,(\rm {Y}=\rm {O,\,S})$ CH 3Y(Y=O,S)
Authors: Grütter M. , Qian X. , Merkt F.
Published: August 2012

Open-shell molecules in doubly degenerate 2E electronic states are subject to the E ⊗ e Jahn-Teller effect and spin-orbit interactions. The rotational structure of the ground vibrational level of the \documentclass[12pt]{minimal}\begin{document}$\tilde{\rm X}^+$\end{document}X̃+ 2E ground state of CH3F+ has been observed by high-resolution photoelectron spectroscopy. In contrast to what is observed in other members of the isoelectronic families \documentclass[12pt]{minimal}\begin{document}$\rm {CH}_3\rm {X}^+\,(\rm {X}=\rm {Cl,\,Br,\,I})$\end{document} CH 3X+(X= Cl , Br ,I) and \documentclass[12pt]{minimal}\begin{document}$\rm {CH}_3\rm {Y}\,(\rm {Y}=\rm {O,\,S})$\end{document} CH 3Y(Y=O,S), the spin-orbit interaction does not lead to a splitting of the ground state of CH3F+. Observed trends in the spectra of the \documentclass[12pt]{minimal}\begin{document}$\tilde{\rm X}$\end{document}X̃ 2E ground states of these molecules are summarized. Whereas certain trends, such as the reduction of the observable effects of the Jahn-Teller interactions and the increase of the spin-orbit splitting with increasing nuclear charge of X and Y are easily understood, other trends are more difficult to explain, such as the much reduced spin-orbit splitting in \documentclass[12pt]{minimal}\begin{document}$\rm {CH}_3\rm {F}^+$\end{document} CH 3F+ compared to \documentclass[12pt]{minimal}\begin{document}$\rm {CH}_3\rm {O}$\end{document} CH 3O. A simple two-state excitonic model is used to account for the trends observed within the series of the methyl-halide radical cations and also the similarities and differences between \documentclass[12pt]{minimal}\begin{document}$\rm {CH}_3\rm {F}^+$\end{document} CH 3F+ and the isoelectronic \documentclass[12pt]{minimal}\begin{document}$\rm {CH}_3\rm {O}$\end{document} CH 3O radical. Within this model, the electron hole in the 2E ground states of \documentclass[12pt]{minimal}\begin{document}$\rm {CH}_3\rm {X}^+$\end{document} CH 3X+ and \documentclass[12pt]{minimal}\begin{document}$\rm {CH}_3\rm {Y}$\end{document} CH 3Y is described in terms of contributions from the halogenic (or chalcogenic) px, y orbitals and the pyramidal-methylic (e) orbitals. This model enables a global, semi-quantitative description of the combined effects of the Jahn-Teller and spin-orbit interactions in these molecules and also a simple interpretation of the spin-orbit-coupling reduction factor ζe.
Computation of effective free surfaces in two phase flows
Authors: Yapalparvi R. , Protas B.
Published: August 2012

In this investigation we revisit the concept of “effective free surfaces” arising in the solution of the time-averaged fluid dynamics equations in the presence of free boundaries. This work is motivated by applications of the optimization and optimal control theory to problems involving free surfaces, where the time-dependent formulations lead to many technical difficulties which are, however, alleviated when steady governing equations are used instead. By introducing a number of precisely stated assumptions we develop and validate an approach in which the interface between the different phases, understood in the time-averaged sense, is sharp. In the proposed formulation, the terms representing the fluctuations of the free boundaries and of the hydrodynamic quantities appear as boundary conditions on the effective surface and require suitable closure models. As a simple model problem we consider impingement of free-falling droplets onto a fluid in a pool with a free surface, and a simple algebraic closure model is proposed for this system. The resulting averaged equations are of the free-boundary type and an efficient computational approach based on shape optimization formulation is developed for their solution. The computed effective surfaces exhibit consistent dependence on the problem parameters and compare favorably with the results obtained when the data from the actual time-dependent problem are used in lieu of the closure model.
Scale dependence of the retarded van der Waals potential
Authors: Miyao Tadahiro , Spohn Herbert
Published: August 2012

We study the ground state energy for a system of two hydrogen atoms coupled to the quantized Maxwell field in the limit α → 0 together with the relative distance between the atoms increasing as α−γR, γ > 0. In particular we determine explicitly the crossover function from the R−6 van der Waals potential to the R−7 retarded van der Waals potential, which takes place at scale α−2R.
A compact high vacuum heating chamber for in-situ x-ray scattering studies
Authors: Bertram F. , Deiter C. , Pflaum K. , Seeck O. H.
Published: August 2012

A very compact multi purpose high vacuum heating chamber for x-ray scattering techniques was developed. The compact design allows the chamber to be installed on high precision diffractometers which usually cannot support heavy and/or large equipment. The chamber is covered by a Be dome allowing full access to the hemisphere above the sample which is required for in-plane grazing incident x-ray diffraction and out-off plane wide angle x-ray diffraction.
Mass-analyzed threshold ionization and structural isomers of M3O4 (M = Sc, Y, and La)
Authors: Wu Lu , Zhang Changhua , Krasnokutski Serge A. , Yang Dong-Sheng
Published: August 2012

M3O4 (M = Sc, Y, and La) were produced in a pulsed laser-vaporization molecular beam source and studied by mass-analyzed threshold ionization (MATI) spectroscopy and electronic structure calculations. Adiabatic ionization energies (AIEs) of the neutral clusters and vibrational frequencies of the cations were measured accurately for the first time from the MATI spectra. Five possible structural isomers of M3O4 were considered in the calculations and spectral analysis. A cage-like structure in C3v point group was identified as the most stable one. The structure is formed by fusing three M2O2 fragments together, each sharing two O–M bonds with others. The ground electronic state of the neutral clusters is 2A1 with the unpaired electron being largely a metal-based s character. Ionization of the 2A1 state yields a 1A1 ion state in a similar geometry to the neutral cluster. The AIEs of the clusters are 4.4556 (6), 4.0586(6), and 3.4750(6) eV for M = Sc, Y, and La, respectively. The observed vibrational modes of the cations include metal-oxygen stretching, metal triangle breathing, and oxygen-metal-oxygen rocking in the frequency range of 200–800 cm−1.
Nonlinear instability saturation due to quasi-particle trapping in a turbulent plasma
Authors: Mendonça J. T. , Benkadda S.
Published: August 2012

We consider the problem of a single wave mode stability, dispersion, and nonlinear saturation in a turbulent plasma background. We adopt a wave kinetic description for the quasi-particle turbulence and assume a low frequency perturbation of both the plasma and the turbulent spectrum. We describe an improved theoretical approach, which goes beyond the geometric optics approximation and retains the recoil effects associated with the emission and absorption of low frequency waves by nearly resonant quasi-particles. We illustrate the present approach by considering the case of zonal flow excited by drift wave turbulence.
Dependences of Brillouin frequency shift on strain and temperature in optical fibers doped with rare-earth ions
Authors: Mizuno Yosuke , Hayashi Neisei , Nakamura Kentaro
Published: August 2012

Brillouin scattering properties in rare-earth-doped fibers, including Nd3+-doped, Tm3+-doped, Sm3+-doped, and Ho3+/Tm3+ co-doped fibers, can potentially be controlled at high speed by pumping, but there has been no report on their detailed investigations. In this study, as the first step toward this goal, the Brillouin gain spectra (BGS) in such rare-earth-doped single-mode fibers are measured, for the first time, at 1.55 μm without pumping, and the Brillouin frequency shift (BFS) and its dependences on strain and temperature are investigated. Clear BGS was observed for the Nd3+-doped and Tm3+-doped fibers, but BGS was not detected for the Sm3+-doped and Ho3+/Tm3+ co-doped fibers probably because of their extremely high propagation losses at 1.55 μm and small Brillouin gain coefficients. The BFS of the Nd3+-doped fiber was ∼10.82 GHz, and its strain and temperature coefficients were 466 MHz/% and 0.726 MHz/K, respectively. As for the Tm3+-doped fiber, the BFS was ∼10.90 GHz, and its strain and temperature coefficients were 433 MHz/% and 0.903 MHz/K, respectively. These measurement results are compared with those of silica fibers.
Deposition and composition-control of Mn-doped ZnO thin films by combinatorial pulsed laser deposition using two delayed plasma plumes
Authors: Sánchez-Aké C. , Camacho R. , Moreno L.
Published: August 2012

Thin films of ZnO doped with manganese were deposited by double-beam, combinatorial pulsed laser deposition. The laser-induced plasmas were studied by means of fast photography and using a Langmuir probe, whereas the films were analyzed by x-ray-diffraction and energy-dispersive x-ray spectroscopy. The effect of the relative delay between plasma plumes on the characteristics of the films was analyzed. It was found that using this parameter, it is possible to control the dopant content keeping the oriented wurtzite structure of the films. The minimum content of Mn was found for plume delays between 0 and 10 μs as the interaction between plasmas scatters the dopant species away from the substrate, thus reducing the incorporation of Mn into the films. Results suggest that for delays shorter than ∼100 μs, the expansion of the second plume through the region behind the first plume affects the composition of the film.
Holographic modification of TiO2 nanostructure for enhanced charge transport in dye-sensitized solar cell
Authors: Lee Jinsoo , Yoon Junghwan , Jin Minhea , Lee Myeongkyu
Published: August 2012

We show that the photocurrent and energy conversion efficiency of dye-sensitized solar cells can be greatly enhanced with holographic modification to the morphology of TiO2 electrode. The nanoporous electrode coated onto conducting glass was irradiated by three interfering laser beams at 1064 nm incident from the backside of the substrate. This generated two-dimensional periodic pillars of higher density in the electrode, through which the photoexcited electrons could be extracted more effectively. The cells fabricated with modified electrodes exhibited average photocurrent and efficiency of 17.14 mA/cm2 and 9.03%, while 14.91 mA/cm2 and 7.83% were obtained from the reference cells. It was attributed to the enhanced charge transport accompanied by the reduction of internal resistance of the electrode.
Deformation mechanisms, size effects, and strain hardening in nanoscale metallic multilayers under nanoindentation
Authors: Shao S. , Zbib H. M. , Mastorakos I. N. , Bahr D. F.
Published: August 2012

The strain hardening and the related surface pile-up phenomena in CuNi, CuNb and CuNiNb nanoscale multilayered metallic (NMM) composites are investigated using atomistic simulations of nanoindentation on such multilayers with varying individual layer thickness. Using empirical load-stress and displacement-strain relations, the obtained load-depth curves were converted to hardness-strain curves which was then fitted using power law. It is found that the extent of surface pile-up is inversely related to the hardening exponent of the NMMs. Two deformations mechanisms which control the surface pile phenomenon are discovered and discussed. Furthermore, from the stress-strain data, it is found that interfaces and their types play a major role in strain hardening; the strain hardening rate increases with strain when incoherent interfaces are present. The relationship between the hardening parameters and the interfacial dislocation density as well as the relationship between interfacial density and length scales, such as layer thickness and indentation depth, are analyzed, and it is found that the hardness in these NMM has strong inverse power law dependence on the layer thickness.
Miniaturized terrestrial digital media broadcasting antenna based on low loss magneto-dielectric materials for mobile handset applications
Authors: Xia Qi , Su Hua , Zhang Tianshui , Li Jie , Shen Guoce , Zhang Huaiwu , Tang Xiaoli
Published: August 2012

In this paper, the low loss magneto-dielectric Co2Z ferrite has been developed for miniaturization of mobile handset antennas. The developed substrate material had almost equal permeability and permittivity of about 12, as well as low magnetic and dielectric loss tangent of about 0.047 and 0.0063 at 200 MHz, which was due to the use of a two-step sintering method. Compared with conventional final-stage sintering method, low magnetic and dielectric loss tangent were found to be a decrease of about 42% and 62%, respectively. A helical antenna operating at VHF band was fabricated on such ferrite substrate. The return loss and Smith chart of the antenna were investigated with a network analyzer. By comparing two different sintering methods, the two-step sintering samples gave better performance in loss tangent and magneto-dielectric properties, which have shown advantages in improving the antenna performance.
Validation of the reaction thermodynamics associated with NaSc(BH4)4 from first-principles calculations: Detecting metastable paths and identifying the minimum free energy path
Authors: Kim Ki Chul
Published: August 2012

A critical drawback with first-principles thermodynamic calculations is the absence of the vibrational and entropic contributions to the prediction of reaction mechanisms, which could conclusively show that the predicted reaction mechanism might be not the most stable reaction path. This study focused on providing an answer to this problem by examining possible metastable paths for five reactant mixtures whose reaction mechanisms were previously predicted using first-principles thermodynamic calculations. The aim of this study was to find a minimum free energy path among all the possible paths of each reactant mixture. This effort provided the clear conclusion that the original reaction paths predicted from first-principles thermodynamic calculations were the most stable reaction paths at an appropriate H2 pressure range for all cases. An additional examination associated with density functional theory uncertainty suggests how the ambiguity of reaction mechanisms predicted based on thermodynamic calculations should be understood and dealt with.
Determination of carrier concentration by Fano interference of Raman scattering in heavily doped n-type 4H-SiC
Authors: Mitani Takeshi , Nakashima Shin-ichi , Kojima Kazutoshi , Kato Tomohisa , Okumura Hajime
Published: August 2012

For n-type 4H-SiC crystals with carrier concentrations between 2 × 1017 and 2.5 × 1020 cm−3, Fano interference of the folded transverse acoustic (FTA) doublet modes was observed. The Fano line-shape parameters were shown to vary with carrier concentration. It is proposed that the peak shifts in the FTA modes resulting from interference with an electronic continuum state can be used to measure carrier concentration for n-type 4H-SiC up to 1020 cm−3. In addition, the relative intensity of the FTA doublet modes varies markedly with carrier concentrations above 5 × 1018 cm−3. This suggests that mode coupling occurs between the FTA doublet components. The variation in the intensity ratio is attributed to the intensity transfer between the FTA doublet components. This mode coupling arises from a phonon-phonon interaction via electronic continuum state-phonon interactions.
Asymmetric radiative damping of low shear toroidal Alfvén eigenmodes
Authors: Nyqvist R. M. , Sharapov S. E.
Published: August 2012

Radiative damping of toroidicity-induced Alfvén eigenmodes (TAEs) in tokamaks, caused by coupling to the kinetic Alfvén wave (KAW), is investigated analytically in the limit of low magnetic shear. A significant asymmetry is found between the radiative damping of the odd TAE, whose frequency lies above the central TAE gap frequency ω0, and that of the even TAE, with frequency ω<ω0. For the even TAE, which consists of a symmetric combination of neighboring poloidal harmonics (and therefore has ballooning-type mode structure), the coupling results in two non-overlapping, outgoing fluxes of KAWs that propagate radially away from each other and the TAE localization region. In contrast, the odd TAE consists of an antisymmetric combination of neighboring poloidal harmonics, resulting in anti-ballooning mode structure. For this mode, the KAWs initially propagate towards each other and form an interference pattern in the TAE localization region, resulting in a negligibly small escaping flux and a correspondingly low radiative damping rate. As a result of the up/down asymmetry in radiative damping with respect to the mode frequency, the odd TAE may be destabilized by fusion born alpha particles more easily than the usual, even TAE.
Experimental study of a compact P-band coaxial relativistic backward wave oscillator with three periods slow wave structure
Authors: Gao Liang , Qian Bao-Liang , Ge Xing-Jun , Zhang Xiao-Ping , Jin Zhen-Xing
Published: August 2012

A compact P-band coaxial relativistic backward wave oscillator with three periods slow wave structure was investigated experimentally. The experimental results show that the frequency of the P-band coaxial relativistic backward wave oscillator is 897 MHz and the microwave power is 1.47 GW with an efficiency of about 32% in the case in which the diode voltage is 572 kV, the beam current is 8.0 kA, and the guide magnetic field is about 0.86 T. In addition, the device can generate a 3.14 GW microwave radiation as the guide magnetic field increases to 1.2 T at the diode voltage of 997 kV and the beam current of 15.3 kA. The experimental results are in good agreement with those obtained earlier by numerical simulations.
Electron magneto-hydrodynamic waves bounded by magnetic bubble
Authors: Anitha V. P. , Sharma D. , Banerjee S. P. , Mattoo S. K.
Published: August 2012

The propagation of electron magneto-hydrodynamic (EMHD) waves is studied experimentally in a 3-dimensional region of low magnetic field surrounded by stronger magnetic field at its boundaries. We report observations where bounded left hand polarized Helicon like EMHD waves are excited, localized in the region of low magnetic field due to the boundary effects generated by growing strengths of the ambient magnetic field rather than a conducting or dielectric material boundary. An analytical model is developed to include the effects of radially nonuniform magnetic field in the wave propagation. The bounded solutions are compared with the experimentally obtained radial wave magnetic field profiles explaining the observed localized propagation of waves.
Surface spin slips in thin holmium films
Authors: Sales F. H. S. , Dantas A. L. , Carriço A. S.
Published: August 2012

We report a theoretical investigation of new spin slips phases of thin holmium (Ho) films. The new phases originate from the loss of coordination of atoms in the near surface region, which affects the balance between exchange and anisotropy energies, favoring the alignment of near surface spins along the basal plane easy axis directions.
Investigation of temperature dependent threshold voltage variation of Gd2O3/AlGaN/GaN metal-oxide-semiconductor heterostructure
Authors: Das Atanu , Chang Liann Be , Lin Ray Ming
Published: August 2012

Temperature dependent threshold voltage (Vth) variation of GaN/AlGaN/Gd2O3/Ni-Au structure is investigated by capacitance-voltage measurement with temperature varying from 25°C to 150°C. The Vth of the Schottky device without oxide layer is slightly changed with respect to temperature. However, variation of Vth is observed for both as-deposited and annealed device owing to electron capture by the interface traps or bulk traps. The Vth shifts of 0.4V and 3.2V are obtained for as-deposited and annealed device respectively. For annealed device, electron capture process is not only restricted in the interface region but also extended into the crystalline Gd2O3 layer through Frenkel-Poole emission and hooping conduction, resulting in a larger Vth shift. The calculated trap density for as-deposited and annealed device is 3.28×1011∼1.12×1011 eV−1cm−2 and 1.74×1012∼7.33×1011 eV−1cm−2 respectively in measured temperature range. These results indicate that elevated temperature measurement is necessary to characterize GaN/AlGaN heterostructure based devices with oxide as gate dielectric.
Disrupting the Public–Private Distinction: Excavating the Government of Carbon Markets Post-Copenhagen
Authors: Lövbrand Eva , Stripple Johannes
Published: August 2012

This paper draws upon the recent carbon market turmoil to understand how the private realm is imagined in global climate governance. Instead of asking which entities (eg, public or private authorities) govern the carbon economy, we draw attention to the procedures (eg, caps on emissions, techniques of verification, or performance standards) by which carbon markets are made thinkable and governable as administrative domains. When focusing on these ‘calculative practices’, carbon market governance does not signify a retreat of the state. Rather, in this paper we argue that the involvement of nonstate actors in the governance of carbon markets represents a transformation of political rule that replaces formal and hierarchical techniques of government with more indirect regimes of calculation. From this vantage point carbon market governance emerges as an expression of a changing rationality of government where the private realm becomes elevated from being a passive terrain to be acted upon and instead turned into an entity that is both object and subject of government.
Privatization and Intermunicipal Contracting: The US Local Government Experience 1992–2007
Authors: Hefetz Amir , Warner Mildred E , Vigoda-Gadot Eran
Published: August 2012

Local government scholars are giving increasing attention to market solutions to urban service delivery. Intermunicipal contracting and privatization are two market approaches to reaching economies of scale. Using national data on over one thousand municipalities from across the United States for the 1992–2007 period, we explore the differences between intermunicipal contracting and privatization and assess how the use of these market approaches relates to efficiency, scale, and public engagement factors. Using probit models for each of four survey years (1992, 1997, 2002, 2007), we find these market solutions are only partial responses to the problem of regional coordination and exhibit important differences with respect to place, management, and political concerns. These market solutions exhibit limited efficiency, equity, and voice benefits.
Popular Perception of Urban Transformation through Megaevents: Understanding Support for the 2014 Winter Olympics in Sochi
Authors: Müller Martin
Published: August 2012

With the increasing number and impact of events hosted by cities, understanding the nature of popular support for them and the resulting urban transformations is a crucial task. I examine residents' perceptions of the preparations for the 2014 Winter Olympic Games in Sochi, asking how support differs across social groups and what factors predict support. I find that negative impacts from preparations dominate public opinion, but that there is nevertheless a solid support base for the event. Support tends to be strongest among non-Russians, the younger generation, and residents who have good knowledge of the preparations. Perception of positive impacts—in particular, expected image improvement—is the strongest predictor of support, while perception of negative impacts shows a much weaker association with support. I conclude that delivering on the positive aspects of events might be more important for administrations than minimizing the negative side effects.
How Climate Change Became a Business Risk: Analyzing Nonstate Agency in Global Climate Politics
Authors: Pattberg Philipp
Published: August 2012

Climate change is widely acknowledged as a key business risk. Companies around the globe are taking action to mitigate their carbon emissions, develop climate-friendly products and services, and prepare for the negative impacts of climate change for their operations. Financial investors, on their part, are becoming more concerned about business responses to climate change and begin to demand concrete risk management strategies. In this context an increasing number of private initiatives are seeking to change business behaviour in a more sustainable direction. Key instruments used are governance by disclosure. This paper explores the agency of nonstate actors in manufacturing climate change into a key business risk, a development that enabled the use of disclosure-based governance mechanisms in global climate politics.
Transnational Public–Private Partnerships' Performance in Water Governance: Institutional Design Matters
Authors: Beisheim Marianne , Campe Sabine
Published: August 2012

Transnational public-private partnerships (PPPs) are new forms of governance that have caught the interest of researchers in recent years. While the literature tends to portray PPPs as loosely institutionalized forms of governance, we argue that PPPs' institutional design varies and matters for their effectiveness. We aim to demonstrate that a high degree of institutionalization (obligation, precision, delegation) is relevant in cases that involve collective action problems—that is, for those PPPs that have to deal with distributional conflict, cheating, or free-riding. To substantiate our argument, we compare and analyze the performance of three transnational water partnerships (not to be confused with municipal for-profit PPPs). Our results confirm that a high degree of institutionalization tends to be important for those water partnerships that implement costly projects. It is less important for those that focus on the comparatively undemanding task of exchanging and disseminating knowledge and best practice in water management and governance.
The state of risk prevention in a sample of Australian hospitals, medical centres and allied health services
Authors: Canyon Deon V.
Published: August 2012

This paper reports on an investigation into five risk prevention factors (technology, people, organisational structure, culture and top management psychology) to inform organisational preparedness planning and to update managers on the state of health care services. Data were collected by means of a 10-question, cross-sectional survey of key decision-making executives in eight different types of 75 health care organisations. Many organisations were found to have deficient risk prevention practices and allied health organisations were considerably worse than health organisations. Forty per cent of hospitals and chiropractic practices had out-dated or poor technology. Results on organisational culture and structure found that many executives associate these factors with risk prevention, but none of them appreciate the relationship between these factors and crisis causation. Gaps and areas for improvement are identified and a change in top management attitude is recommended to address resource allocation and implement appropriate risk prevention systems and mechanisms. Reactive managers need to increase their awareness of risks in order to become capable of preventing them. Proactive managers are those who invest in risk prevention.
Spindle assembly checkpoint regulation of chromosome segregation in mammalian oocytes
Authors: Polanski Zbigniew
Published: August 2012

The spindle assembly checkpoint (SAC) is a surveillance mechanism that monitors the quality of the spindle during division and blocks anaphase entry in the presence of anomalies that could result in erroneous segregation of the chromosomes. Because human aneuploidy is mainly linked to the erroneous segregation of genetic material in oocytes, the issue of the effectiveness of the SAC in female meiosis is especially important. The present review summarises our understanding of the SAC control of mammalian oocyte meiosis, including its possible impact on the incidence of embryonic aneuploidy. Owing to the peculiarities of cell cycle control in female meiosis, the integration of the SAC within such a specific environment results in several unusual situations, which are also discussed.
Structural insights into the editing of germ-line–encoded interactions between T-cell receptor and MHC class II by Vα CDR3
Authors: Deng Lu , Langley Ries J. , Wang Qian , Topalian Suzanne L. , Mariuzza Roy A.
Published: August 2012

The conserved diagonal docking mode observed in structures of T-cell receptors (TCRs) bound to peptide–MHC ligands is believed to reflect coevolution of TCR and MHC genes. This coevolution is supported by the conservation of certain interactions between the germ-line–encoded complementarity-determining region (CDR)1 and CDR2 loops of TCR and MHC. However, the rules governing these interactions are not straightforward, even when the same variable (V) region recognizes the same MHC molecule. Here, we demonstrate that the somatically generated CDR3 loops can markedly alter evolutionarily selected contacts between TCR and MHC (“CDR3 editing”). To understand CDR3 editing at the atomic level, we determined the structure of a human melanoma-specific TCR (G4) bound to the MHC class II molecule HLA-DR1 and an epitope from mutant triose phosphate isomerase (mutTPI). A comparison of the G4–mutTPI–DR1 complex with a complex involving a TCR (E8) that uses the same Vα region to recognize the same mutTPI–DR1 ligand as G4 revealed that CDR1α adopts markedly different conformations in the two TCRs, resulting in an almost entirely different set of contacts with MHC. Based on the structures of unbound G4 and E8, the distinct conformations of CDR1α in these TCRs are not induced by binding to mutTPI–DR1 but result from differences in the length and sequence of CDR3α that are transmitted to CDR1α. The editing of germ-line–encoded TCR–MHC interactions by CDR3 demonstrates that these interactions possess sufficient intrinsic flexibility to accommodate large structural variations in CDR3 and, consequently, in the TCR-binding site.
Actors, observers, and the estimation of task duration
Authors: Roy Michael M. , Christenfeld Nicholas J. S. , Jones Meghan
Published: August 2012

People are often wrong in estimating both how long tasks have taken in the past and how long they will take in the future. Bias could be due to factors such as task involvement, an individual's engagement or motivation in completing the task, or aspects of the task such as its relative duration or memory storage size associated with it. We examined time estimation bias in actors (likely to experience high levels of task involvement) and observers (likely to experience low levels of task involvement) for both predictions of and memory of task duration. Results suggest that bias appears to be due to memory storage size rather than to involvement with the task.
Paying the price works: Increasing goal-state access cost improves problem solving and mitigates the effect of interruption
Authors: Morgan Phillip L. , Patrick John
Published: August 2012

The aim of this paper was to investigate whether it was possible to induce more internal planning in the four-disk Tower of Hanoi (ToH) in order not only to produce more efficient problem solving but also to make it more resistant to the negative effect of interruption. The theoretical frameworks of soft constraints and the memory for goals model underpinned Experiments 1 and 2. In both experiments, three goal-state access cost conditions were used: high (mouse movements and 2.5-s delay), medium (mouse movements) and low (goal state always available). In Experiment 1, more memory-based planning was induced by the high cost condition, which resulted in fewer moves to solution and the gradual development of an efficient subgoaling strategy, resulting in more perfect solutions. In Experiment 2, the same condition protected performance against a 10-s interruption irrespective of the interrupting task (blank screen, mental arithmetic, or three-disk ToH). The more memory-based planning strategy, induced by high access cost, presumably strengthened participants' goals during planning and problem solving, making them less susceptible to decay and interference from interruption. These novel results are discussed in the context of other recent studies.
Kinematics matters: A new eye-tracking investigation of animated triangles
Authors: Roux Paul , Passerieux Christine , Ramus Franck
Published: August 2012

Eye movements have been recently recorded in participants watching animated triangles in short movies that normally evoke mentalizing (Frith–Happé animations). Authors have found systematic differences in oculomotor behaviour according to the degree of mental state attribution to these triangles: Participants made longer fixations and looked longer at intentional triangles than at triangles moving randomly. However, no study has yet explored kinematic characteristics of Frith–Happé animations and their influence on eye movements. In a first experiment, we have run a quantitative kinematic analysis of Frith–Happé animations and found that the time triangles spent moving and the distance between them decreased with the mentalistic complexity of their movements. In a second experiment, we have recorded eye movements in 17 participants watching Frith–Happé animations and found that some differences in fixation durations and in the proportion of gaze allocated to triangles between the different kinds of animations were entirely explained by low-level kinematic confounds. We finally present a new eye-tracking measure of visual attention, triangle pursuit duration, which does differentiate the different types of animations even after taking into account kinematic cofounds. However, some idiosyncratic kinematic properties of the Frith–Happé animations prevent an entirely satisfactory interpretation of these results. The different eye-tracking measures are interpreted as implicit and line measures of the processing of animate movements.
Is “Inhibition of Return” due to the inhibition of the return of attention?
Authors: Martín-Arévalo Elisa , Kingstone Alan , Lupiáñez Juan
Published: August 2012

Inhibition of Return (IOR) is usually explained in terms of orienting–reorienting of attention, emphasizing an underlying mechanism that inhibits the return of attention to previously selected locations. Recent data challenge this explanation to the extent that the IOR effect is observed at the location where attention is oriented to, where no reorienting of attention is needed. To date, these studies have involved endogenous attentional selection of attention and thus indicate a dissociation between the voluntary attention of spatial attention and the IOR effect. The present work demonstrates a dissociation between the involuntary orienting of spatial attention and the IOR effect. We combined nonpredictive peripheral cues with nonpredictive central orienting cues (either arrows or gaze). The IOR effect was observed to operate independent of involuntary spatial orienting. These data speak against the “ reorienting hypothesis” of IOR. We suggest an alternative explanation whereby the IOR effect reflects a cost in detecting a new event (the target) at the location where another event (a cue) was coded before.
The contextual interference effect in visual feature binding: What does it say about the role of attention in binding?
Authors: Jaswal Snehlata , Logie Robert H.
Published: August 2012

The effects of blocked versus mixed presentation were tested on visual feature binding, assuming that blocked presentation enhances focused attention, whilst mixed presentation recruits extra attentional resources for intratrial as well as intertrial processing. The contextual interference effect suggests that although performance due to mixed presentation is either similar or worse than blocked presentation when tested immediately, it is better when tested after an interval. We explored whether this robust empirical effect, common in psychomotor performance, would be evident in visual feature binding. Stimuli were conjunctions of shape, colour, and location. Study–test intervals from 0 to 2,500 ms were used with a swap detection task. In Experiments 1A and 1B, participants ignored locations to detect shape–colour bindings. In Experiments 2A and 2B, they ignored shapes to detect colour–location binding. In Experiments 3A and 3B, they ignored colours to detect shape–location bindings. Whilst Experiments 1A, 2A, and 3A used blocked presentation, Experiments 1B, 2B, and 3B used mixed presentation of study–test intervals. The results of these experiments and a replication experiment using a within-subjects design showed that the contextual interference effect appeared when spatial attention was engaged, but not when attention was object based.
Efficient modification of the surface properties of interconnected porous hydroxyapatite by low-pressure low-frequency plasma treatment to promote its biological performance
Authors: Lee Dae-Sung , Moriguchi Yu , Myoui Akira , Yoshikawa Hideki , Hamaguchi Satoshi
Published: August 2012

Dielectric barrier discharge plasma treatment at low pressure is found to significantly improve the biological performance of artificial bones made of interconnected porous calcium hydroxyapatite (IP-CHA). One of the essential parameters associated with their biological performance is hydrophilicity of their exterior surfaces as well as surfaces of inner pores. It is found that plasma treatment at low pressures is highly effective in making the inner pore surfaces more hydrophilic. Preliminary in vivo experiments of plasma-treated IP-CHA artificial bones in rats have shown fast formation of blood vessels in their inner pores, implying the increase in osteoconductivity due to the plasma treatment.
Aerosol growth in a medium with temperature gradient
Authors: Nemchinsky Valerian
Published: August 2012

The simple method of modelling aerosol growth developed in our previous paper (Nemchinsky and Shigeta 2012 Modelling Simul. Mater. Sci. Eng.
20 045017) is used to model nanoparticle growth in a plasma reactor with gas flow and steep temperature gradient. It is shown that depending on the parameters of the precursor monomers at the entrance of the reactor zone, an increase in gas speed could either increase or decrease the final nanoparticles' size at the exit of the reaction zone.
Phase composition and tribomechanical properties of Ti–B–C nanocomposite coatings prepared by magnetron sputtering
Authors: Sánchez-López J C , Abad M D , Justo A , Gago R , Endrino J L , García-Luis A , Brizuela M
Published: August 2012

Protective nanocomposite coatings based on hard ceramic phases (TiC, TiB2) combined with amorphous carbon (a-C) are of interest because of their adequate balance between mechanical and tribological performances. In this work, Ti–B–C nanocomposite coatings were prepared by co-sputtering of graphite and TiB2 targets. Varying the discharge power ratio applied to the graphite and TiB2 targets from 0 to 2, the a-C content in the coatings could be tuned from 0 to 60%, as observed by means of Raman and x-ray photoelectron spectroscopy (XPS). The microstructural characterization demonstrated a progressive decrease in crystallinity from an initial nanocrystalline (nc) TiB2-like structure to a distorted TiB
x
C
y
ternary compound with increasing C concentration. X-ray absorption near-edge structure measurements on the B K-edge helped to determine a hexagonal arrangement around the B atoms in the ternary TiB
x
C
y
phase. A fitting analysis of the C 1s XPS peak allowed us to evaluate the relative amount of a-C and TiB
x
C
y
components. A drastic change in hardness (from 52 to 13 GPa) and friction coefficient values (from 0.8 to 0.2) is noticed when moving from nc-TiB2 to TiBC/a-C nanocomposites. The fraction of a-C necessary to decrease the friction below 0.2 was found to be 45%. Raman observation of the wear tracks determined the presence of disordered sp2-bonded carbon phase associated with the diminution of the friction level.
Alfvén eigenmode structure during off-axis neutral beam injection
Authors: Tobias B. , Bass E.M. , Classen I.G.J. , Domier C.W. , Grierson B.A. , Heidbrink W.W. , Luhmann N.C. , Nazikian R. , Park H.K. , Spong D.A. , Zeeland M.A. Van
Published: August 2012

The spatial structure of Alfvén eigenmodes on the DIII-D tokamak is compared for contrasting fast ion deposition profiles resulting from on- and off-axis neutral beam injection (NBI). In both cases, poloidal mode rotation and eigenmode twist, or radial phase variation, are correlated with the direction of the normal ion diamagnetic flow and readily inverted with a reversal of toroidal magnetic field, B
T. While off-axis NBI results in weakly driven reversed shear induced Alfvén eigenmodes due to reduced fast ion pressure gradient, ∇β
fast, in the region of the mode, these marginally unstable modes exhibit a 2D phase structure that is indistinguishable from that observed during on-axis injection. This result is consistent with recent explorations using the non-perturbative codes Gyro and TAEFL that show a weak dependence of eigenmode structure on drive when fast ion density is uniformly reduced by a scalar multiplier. These codes also obtain unstable, counter-propagating modes with the inverted 2D phase structure when B
T is kept constant and the diamagnetic flow direction is reversed by making ∇β
fast sufficiently positive for an isotropic population of fast ions. While measurements of the spatial profile of fast ion D-α light from the recently upgraded charge exchange recombination diagnostic on DIII-D suggest a strong modification of fast ion pressure towards this limit, no counter-propagating modes have yet been observed in experiment.
The unified effect of counter-toroidal rotation and power across separatrix on type-I ELMs in JT-60U
Authors: Urano H. , Oyama N. , Kamiya K. , Aiba N. , Kamada Y. , Fujita T.
Published: August 2012

By conducting power scan experiments using perpendicular neutral beams (NBs) after the injection of tangential NBs in directions co-, balanced and counter to the plasma current, the unified effect of counter-toroidal rotation and heating power on type-I edge-localized modes (ELMs) was investigated in a JT-60U tokamak. ELM frequency f
ELM increased monotonically together with the power across the separatrix P
sep for all the cases of tangential NBs. However, dependence of f
ELM on P
sep was explicitly stronger than a simple proportionality when perpendicular NBs were injected. The toroidal rotation velocity at the H-mode pedestal

shifted continuously in the counter-direction when perpendicular NBs were applied. At fixed values of

, f
ELM increased clearly in proportion to P
sep. In addition, this proportionality between f
ELM and P
sep holds regardless of the mixture of datasets of the toroidal momentum inputs. The proportional coefficient decreased as

shifted in the co-direction.
Toric Hirzebruch-Riemann-Roch via Ishida’s theorem on the Todd genus
Authors: Schenck Hal
Published: August 2012

We give a simple proof of the Hirzebruch-Riemann-Roch theorem for smooth complete toric varieties, based on Ishida’s result that the Todd genus of a smooth complete toric variety is one.
Validation: What Big Data Reveal About Survey Misreporting and the Real Electorate
Authors: Ansolabehere Stephen , Hersh Eitan
Published: August 2012

Social scientists rely on surveys to explain political behavior. From consistent overreporting of voter turnout, it is evident that responses on survey items may be unreliable and lead scholars to incorrectly estimate the correlates of participation. Leveraging developments in technology and improvements in public records, we conduct the first-ever fifty-state vote validation. We parse overreporting due to response bias from overreporting due to inaccurate respondents. We find that nonvoters who are politically engaged and equipped with politically relevant resources consistently misreport that they voted. This finding cannot be explained by faulty registration records, which we measure with new indicators of election administration quality. Respondents are found to misreport only on survey items associated with socially desirable outcomes, which we find by validating items beyond voting, like race and party. We show that studies of representation and participation based on survey reports dramatically misestimate the differences between voters and nonvoters.