bluuebunny/crossref_metadata_2025 huggingface dataset:
Two-dimensional solitons in spin nematic states for magnets with an isotropic exchange interaction
Authors: Galkina E. G. , Ivanov B. A. , Kosmachev O. A. , Fridman Yu. A.
Published: May 2015

A study of two-dimensional topological vortex-like solitons, for spin nematic states in magnets with spin S = 1 and S = 3/2. Depending on the parameters of the magnet, we get either pure multipole vortices, with a quadrupole parameter for S = 1, or an octupole parameter for S = 3/2, or vortices with a non-singular core. A vortex core corresponds to a macroscopic area with a disrupted nematic order. A transition to core vortices occurs at critical values of the system parameters. In this case, there is either the formation of a ferromagnetic vortex with a saturated magnetic moment in the core, or a vortex with an antiferromagnetic order at the core. The dynamic properties of the vortex with a ferromagnetic core are characterized by the presence of a gyroforce, whereas vortices with an antiferromagnetic core are Lorentz-invariant, which is typical for sigma-model antiferromagnets.
A simple stochastic quadrant model for the transport and deposition of particles in turbulent boundary layers
Authors: Jin C. , Potts I. , Reeks M. W.
Published: May 2015

We present a simple stochastic quadrant model for calculating the transport and deposition of heavy particles in a fully developed turbulent boundary layer based on the statistics of wall-normal fluid velocity fluctuations obtained from a fully developed channel flow. Individual particles are tracked through the boundary layer via their interactions with a succession of random eddies found in each of the quadrants of the fluid Reynolds shear stress domain in a homogeneous Markov chain process. In this way, we are able to account directly for the influence of ejection and sweeping events as others have done but without resorting to the use of adjustable parameters. Deposition rate predictions for a wide range of heavy particles predicted by the model compare well with benchmark experimental measurements. In addition, deposition rates are compared with those obtained from continuous random walk models and Langevin equation based ejection and sweep models which noticeably give significantly lower deposition rates. Various statistics related to the particle near wall behavior are also presented. Finally, we consider the model limitations in using the model to calculate deposition in more complex flows where the near wall turbulence may be significantly different.
Codimension three bifurcation of streamline patterns close to a no-slip wall: A topological description of boundary layer eruption
Authors: Balci A. , Andersen M. , Thompson M. C. , Brøns M.
Published: May 2015

A vortex close to a no-slip wall gives rise to the creation of new vorticity at the wall. This vorticity may organize itself into vortices that erupt from the separated boundary layer. We study how the eruption process in terms of the streamline topology is initiated and varies in dependence of the Reynolds number Re. We show that vortex structures are created in the boundary layer for Re around 600, but that these disappear again without eruption unless Re > 1000. The eruption process is topologically unaltered for Re up to 5000. Using bifurcation theory, we obtain a topological phase space for the eruption process, which can account for all observed changes in the Reynolds number range we consider. The bifurcation diagram complements previously analyzes such that the classification of topological bifurcations of flows close to no-slip walls with up to three parameters is now complete.
Representing the thermal state in time-dependent density functional theory
Authors: Modine N. A. , Hatcher R. M.
Published: May 2015

Classical molecular dynamics (MD) provides a powerful and widely used approach to determining thermodynamic properties by integrating the classical equations of motion of a system of atoms. Time-Dependent Density Functional Theory (TDDFT) provides a powerful and increasingly useful approach to integrating the quantum equations of motion for a system of electrons. TDDFT efficiently captures the unitary evolution of a many-electron state by mapping the system into a fictitious non-interacting system. In analogy to MD, one could imagine obtaining the thermodynamic properties of an electronic system from a TDDFT simulation in which the electrons are excited from their ground state by a time-dependent potential and then allowed to evolve freely in time while statistical data are captured from periodic snapshots of the system. For a variety of systems (e.g., many metals), the electrons reach an effective state of internal equilibrium due to electron-electron interactions on a time scale that is short compared to electron-phonon equilibration. During the initial time-evolution of such systems following electronic excitation, electron-phonon interactions should be negligible, and therefore, TDDFT should successfully capture the internal thermalization of the electrons. However, it is unclear how TDDFT represents the resulting thermal state. In particular, the thermal state is usually represented in quantum statistical mechanics as a mixed state, while the occupations of the TDDFT wavefunctions are fixed by the initial state in TDDFT. We work to address this puzzle by (A) reformulating quantum statistical mechanics so that thermodynamic expectations can be obtained as an unweighted average over a set of many-body pure states and (B) constructing a family of non-interacting (single determinant) TDDFT states that approximate the required many-body states for the canonical ensemble.
Three-dimensional modeling of propagating precipitation waves
Authors: Tinsley Mark R. , Collison Darrell , Showalter Kenneth
Published: May 2015

A general three-dimensional model for propagating precipitation waves is presented. Structural features identified in experimental studies of propagating waves in the AlCl3/NaOH and NaAl(OH)4/HCl systems are described by the 3D model. Two forms of precipitate with different physical properties play key mechanistic roles in the wave propagation. Experimentally observed circular and spiral waves are simulated by the 3D model, as well as wave annihilation on the collision of two waves.
Equivalence between a generalized dendritic network and a set of one-dimensional networks as a ground of linear dynamics
Authors: Koda Shin-ichi
Published: May 2015

It has been shown by some existing studies that some linear dynamical systems defined on a dendritic network are equivalent to those defined on a set of one-dimensional networks in special cases and this transformation to the simple picture, which we call linear chain (LC) decomposition, has a significant advantage in understanding properties of dendrimers. In this paper, we expand the class of LC decomposable system with some generalizations. In addition, we propose two general sufficient conditions for LC decomposability with a procedure to systematically realize the LC decomposition. Some examples of LC decomposable linear dynamical systems are also presented with their graphs. The generalization of the LC decomposition is implemented in the following three aspects: (i) the type of linear operators; (ii) the shape of dendritic networks on which linear operators are defined; and (iii) the type of symmetry operations representing the symmetry of the systems. In the generalization (iii), symmetry groups that represent the symmetry of dendritic systems are defined. The LC decomposition is realized by changing the basis of a linear operator defined on a dendritic network into bases of irreducible representations of the symmetry group. The achievement of this paper makes it easier to utilize the LC decomposition in various cases. This may lead to a further understanding of the relation between structure and functions of dendrimers in future studies.
Single Hit Energy-resolved Laue Diffraction
Authors: Patel Shamim , Suggit Matthew J. , Stubley Paul G. , Hawreliak James A. , Ciricosta Orlando , Comley Andrew J. , Collins Gilbert W. , Eggert Jon H. , Foster John M. , Wark Justin S. , Higginbotham Andrew
Published: May 2015

In situ white light Laue diffraction has been successfully used to interrogate the structure of single crystal materials undergoing rapid (nanosecond) dynamic compression up to megabar pressures. However, information on strain state accessible via this technique is limited, reducing its applicability for a range of applications. We present an extension to the existing Laue diffraction platform in which we record the photon energy of a subset of diffraction peaks. This allows for a measurement of the longitudinal and transverse strains in situ during compression. Consequently, we demonstrate measurement of volumetric compression of the unit cell, in addition to the limited aspect ratio information accessible in conventional white light Laue. We present preliminary results for silicon, where only an elastic strain is observed. VISAR measurements show the presence of a two wave structure and measurements show that material downstream of the second wave does not contribute to the observed diffraction peaks, supporting the idea that this material may be highly disordered, or has undergone large scale rotation.
Characteristic oscillatory motion of a camphor boat sensitive to physicochemical environment
Authors: Nakata S. , Yoshii M. , Matsuda Y. , Suematsu N. J.
Published: May 2015

A self-propelled camphor boat on water was investigated from the viewpoint of characteristic features of motion and mode-bifurcation depending on the diffusion length of camphor molecules. When a camphor disk was connected to the bottom of a larger plastic plate and then was placed on water, either oscillatory motion (repetition between rest and motion) or continuous motion was observed. In this paper, we report the novel features of this motion and mode-bifurcation as a function of the diffusion length of camphor molecules, e.g., multiple accelerations during oscillation, period-2 or irregular oscillatory motion, and reciprocating oscillation. These characteristic motion and mode-bifurcation are discussed in relation to the diffusion length of camphor molecules under the camphor boat and the development of camphor molecules from the camphor boat on water.
Impact of microfluidic processing on bacterial ribonucleic acid expression
Authors: Gandi Senthil Kumar , Watson David , Kersaudy-Kerhoas Maïwenn , Desmulliez Marc P. Y. , Bachmann Till , Bridle Helen
Published: May 2015

Bacterial transcriptomics is widely used to investigate gene regulation, bacterial susceptibility to antibiotics, host-pathogen interactions, and pathogenesis. Transcriptomics is crucially dependent on suitable methods to isolate and detect bacterial RNA. Microfluidics offer ways of creating integrated point-of-care systems, analysing a sample from preparation, and RNA isolation to detection. A critical requirement for on-chip diagnostics to deliver on their promise is that mRNA expression is not altered via microfluidic sample processing. This article investigates the impact of the use of microfluidics upon RNA expression of bacteria isolated from blood, a key step towards proving the suitability of such systems for further development.
Arrays of ZnO/CuInxGa1−xSe2 nanocables with tunable shell composition for efficient photovoltaics
Authors: Akram Muhammad Aftab , Javed Sofia , Xu Jun , Mujahid Mohammad , Lee Chun-Sing
Published: May 2015

Arrays of one-dimensional (1D) nanostructure are receiving much attention for their optoelectronic and photovoltaic applications due to their advantages in light absorption, charge separation, and transportation. In this work, arrays of ZnO/CuInxGa1−xSe2 core/shell nanocables with tunable shell compositions over the full range of 0 ≤ x ≤ 1 have been controllably synthesized. Chemical conversions of ZnO nanorods to a series of ZnO-based nanocables, including ZnO/ZnSe, ZnO/CuSe, ZnO/CuSe/InxGa1−x, ZnO/CuSe/(InxGa1−x)2Se3, and ZnO/CuInxGa1−xSe2, are well designed and successfully achieved. Composition-dependent influences of the CuInxGa1−xSe2 shells on photovoltaic performance are investigated. It is found that the increase in indium content (x) leads to an increase in short-circuit current density (JSC) but a decrease in open-circuit voltage (VOC) for the ZnO/CuInxGa1−xSe2 nanocable solar cells. An array of ZnO/CuIn0.67Ga0.33Se2 nanocables with a length of ∼1 μm and a shell thickness of ∼10 nm exhibits a bandgap of 1.20 eV, and yields a maximum power conversion efficiency of 1.74% under AM 1.5 G illumination at an intensity of 100 mW/cm2. It dramatically surpasses that (0.22%) of the ZnO/CuIn0.67Ga0.33Se2 planar thin-film device. Our work reveals that 1D nanoarray allows efficient photovoltaics without using toxic CdS buffer layer.
Electromagnetic resonant modes of dielectric sphere bilayers
Authors: Andueza A. , Pérez-Conde J. , Sevilla J.
Published: May 2015

Sphere bilayers have been proposed as promising structures for electromagnetic management in photonic crystal devices. These arrangements are made of two intertwined subsets of spheres of different size and refractive index, one subset filling the interstitial sites of the other. We present a systematic study of the electromagnetic resonant modes of the bilayers, in comparison with those of the constituent subsets of spheres. Three samples were built with glass and Teflon spheres and their transmission spectra measured in the microwave range (10–25 GHz). Simulations with finite integration time-domain method are in good agreement with experiments. Results show that the bilayer presents the same resonances as one of the subsets but modified by the presence of the other in its resonant frequencies and in the electric field distributions. As this distortion is not very large, the number of resonances in a selected spectral region is determined by the dominant subset. The degree of freedom that offers the bilayer could be useful to fine tune the resonances of the structure for different applications. A map of modes useful to guide this design is also presented. Scale invariance of Maxwell equations allows the translation of these results in the microwave range to the visible region; hence, some possible applications are discussed in this framework.
A semi-empirical equation for the response time of in-plane switching liquid crystal display and measurement of twist elastic constant
Authors: Xu Daming , Peng Fenglin , Tan Guanjun , He Juan , Wu Shin-Tson
Published: May 2015

A semi-empirical equation is developed to characterize the optical decay time of in-plane switching (IPS) and fringe field switching (FFS) liquid crystal displays. This equation takes the effects of elastic constants, cell gap, liquid crystal material, rubbing angle, and anchoring strength into account simultaneously. Good agreement between simulation and experiment is obtained. Moreover, this equation can be used to measure the twist elastic constant K22 of liquid crystals. The measured temperature-dependent K22 values of 5CB agree well with previously published results. Hence, our equation not only describes the response time of IPS and FFS cells but also provides a simple yet accurate method to determine the twist elastic constant of liquid crystal materials.
Self-modulated nanostructures in super-large-period Bi11(Fe5CoTi3)10/9O33 epitaxial thin films
Authors: Meng Dechao , Zhai Xiaofang , Ma Chao , Huang Haoliang , Yun Yu , Huang Yan , Fu Zhengping , Peng Ranran , Mao Xiangyu , Chen Xiaobing , Brown Gail , Lu Yalin
Published: May 2015

Super-large-period Aurivillius thin films with a pseudo-period of ten were grown on (0 0 1) SrTiO3 substrates using the pulsed laser deposition method. The as-grown films are found to be coherently strained to the substrate and atomically smooth. X-ray diffraction indicates an average periodicity of ten, while analysis with the high resolution scanning transmission electron microscopy reveals a self-modulated nanostructure in which the periodicity changes as the film thickness increases. Finally, we discuss the magnetic and possible ferroelectric properties of the self-modulated large period Aurivillius films at the room temperature.
Semiconductor to metallic transition in bulk accumulated amorphous indium-gallium-zinc-oxide dual gate thin-film transistor
Authors: Chun Minkyu , Chowdhury Md Delwar Hossain , Jang Jin
Published: May 2015

We investigated the effects of top gate voltage (VTG) and temperature (in the range of 25 to 70 oC) on dual-gate (DG) back-channel-etched (BCE) amorphous-indium-gallium-zinc-oxide (a-IGZO) thin film transistors (TFTs) characteristics. The increment of VTG from -20V to +20V, decreases the threshold voltage (VTH) from 19.6V to 3.8V and increases the electron density to 8.8 x 1018cm−3. Temperature dependent field-effect mobility in saturation regime, extracted from bottom gate sweep, show a critical dependency on VTG. At VTG of 20V, the mobility decreases from 19.1 to 15.4 cm2/V ⋅ s with increasing temperature, showing a metallic conduction. On the other hand, at VTG of - 20V, the mobility increases from 6.4 to 7.5cm2/V ⋅ s with increasing temperature. Since the top gate bias controls the position of Fermi level, the temperature dependent mobility shows metallic conduction when the Fermi level is above the conduction band edge, by applying high positive bias to the top gate.
Polar twin boundaries and nonconventional ferroelectric switching
Authors: Salje Ekhard K. H. , Li Suzhi , Zhao Ziyuan , Gumbsch Peter , Ding Xiangdong
Published: May 2015

Polar twin wall properties in non-polar or weakly polar matrices can be switched by electric fields with a well-defined ferroelectric hysteresis. While the bulk is nonpolar or weakly polar, the ferroelectric hysteresis stems from the interplay of the field-induced polarization in the bulk and the rotation of the dipole moments in the twin walls. While each tilt of a dipole would be a linear function of the applied field, their combination leads to frustration: The boundary polarity hinders the development of the bulk polarity for weak fields perpendicular to the twin walls. Only when the boundary polarity is sufficiently rotated under stronger fields do we find a sudden collapse of the frustration and the rapid development of bulk polarity. This effect suggests that wall polarity (as observed in CaTiO3 and SrTiO3) may lead to nonconventional ferroelectric switching including the bulk rather than exclusively inside domain walls.
Tunable biaxial in-plane compressive strain in a Si nanomembrane transferred on a polyimide film
Authors: Kim Munho , Mi Hongyi , Cho Minkyu , Seo Jung-Hun , Zhou Weidong , Gong Shaoqin , Ma Zhenqiang
Published: May 2015

A method of creating tunable and programmable biaxial compressive strain in silicon nanomembranes (Si NMs) transferred onto a Kapton® HN polyimide film has been demonstrated. The programmable biaxial compressive strain (up to 0.54%) was generated utilizing a unique thermal property exhibited by the Kapton HN film, namely, it shrinks from its original size when exposed to elevated temperatures. The correlation between the strain and the annealing temperature was carefully investigated using Raman spectroscopy and high resolution X-ray diffraction. It was found that various amounts of compressive strains can be obtained by controlling the thermal annealing temperatures. In addition, a numerical model was used to evaluate the strain distribution in the Si NM. This technique provides a viable approach to forming in-plane compressive strain in NMs and offers a practical platform for further studies in strain engineering.
Direct observation of DNA overwinding by reverse gyrase
Authors: Ogawa Taisaku , Yogo Katsunori , Furuike Shou , Sutoh Kazuo , Kikuchi Akihiko , Kinosita Kazuhiko
Published: May 2015

Significance

Reverse gyrase resides in bacteria that live in hot conditions. The enzyme further intertwines the double helix of DNA to make it tighter. In biochemical assays, reverse gyrase appears quite inefficient, requiring many enzyme molecules per DNA and yet taking many minutes to wind it up. Here, we show that one reverse gyrase molecule rapidly overwinds relaxed DNA but begins to idle as torsion accumulates. Excess torsion would hamper replication/transcription activities, whereas quick restoration of modest torsion prevents thermal denaturation of DNA. We discuss how reverse gyrase lets one strand of DNA pass the other in a preferred direction to achieve overwinding.
Liver X receptors alpha and beta promote myelination and remyelination in the cerebellum
Authors: Meffre Delphine , Shackleford Ghjuvan’Ghjacumu , Hichor Mehdi , Gorgievski Victor , Tzavara Eleni T. , Trousson Amalia , Ghoumari Abdel M. , Deboux Cyrille , Nait Oumesmar Brahim , Liere Philippe , Schumacher Michael , Baulieu Etienne-Emile , Charbonnier Frédéric , Grenier Julien , Massaad Charbel
Published: May 2015

Significance

Liver X receptors (LXRs) α and β are the two major receptors of oxysterols, oxygenated derivatives of cholesterol. They control the homeostasis of cholesterol, an important lipid constituent of myelin sheaths. In the central nervous system, these insulating structures are generated by oligodendrocytes and are stabilized by myelin proteins. Here, we provide evidence of a new role of LXRs in the myelin physiology of the cerebellum. Mice invalidated for both LXRs exhibit alteration in motor coordination and spatial learning linked with myelination deficits. We demonstrated that LXRs intervene both in oligodendroglial cell maturation and in the transcriptional control of myelin gene expression during (re)myelination processes.
The M-word
Authors: Vergis Nikos , Terkourafi Marina
Published: May 2015

We investigate the conventionalization of mock impoliteness through a study of the Greek collocation re malaka, which can be construed as either solidary (dude) or insulting (asshole). Questionnaire results showed that the solidary sense prevails across the board, in contrast to the insulting sense, about which consensus was much lower. We propose that, when the expression is used between young males in a close relationship, the Banter Principle (Leech 1983) is no longer in operation and no inference is needed to disambiguate the interactional import of the collocation. Rather, the solidary sense, having resulted from a “conventionalization of invited inferences” (Traugott 1999), is activated automatically in this “minimal context” (Terkourafi 2005). Our study has implications for the debates on the inherent nature of im/politeness and on the semantics/pragmatics interface from the perspective of im/politeness research.
“There’s not a lot of negotiation”
Authors: Burt Susan M.
Published: May 2015

One way that communities with status or power hierarchy can mark hierarchical relationships is by means of address. Community members may differ in attitude towards the hierarchy and prefer address reflecting imagined or preferred social distance, or social meanings other than the classic power-solidarity semantic of Brown and Gilman (1960). This paper reports on research within an academic unit, in which members of different “ranks,” undergraduate student, graduate student, and faculty, participated in group interviews on the topic of address terms. Different relational and interactional goals emerge for each group. While faculty are sometimes willing to make their varied address preferences clear, students find faculty preferences less than transparent. Graduate students face difficult choices, needing to negotiate address preferences with their undergraduate students as well as with faculty.
Interactional competence and politeness
Authors: Baxter Robert Patrick
Published: May 2015

Few studies in politeness research have examined perception, and even fewer have examined perception at the level of discourse. Salient characteristics of discourse, turn-taking and collaborative talk have been linked to politeness. This study approaches collaborative talk from an unexplored perspective: experimental testing of speaker perception of collaborative talk according to the features of content and timing. This study quantitatively compared native and non-native perceptions of dialogues in Spanish, employing a new aural task which presented listeners with a turn followed by multiple possible responses. The instrument measured the perceived appropriateness of content (matched vs. unmatched) and timing in overlap, and how additional factors influenced perception. Evaluation of collaborative talk was influenced by different features for natives and non-natives.
Utilization of Bacillus sp. strain TAT105 as a biological additive to reduce ammonia emissions during composting of swine feces
Authors: Kuroda Kazutaka , Waki Miyoko , Yasuda Tomoko , Fukumoto Yasuyuki , Tanaka Akihiro , Nakasaki Kiyohiko
Published: May 2015

Bacillus sp. strain TAT105 is a thermophilic, ammonium-tolerant bacterium that grows assimilating ammonium nitrogen and reduces ammonia emission during composting of swine feces. To develop a practical use of TAT105, a dried solid culture of TAT105 (5.3 × 109 CFU/g of dry matter) was prepared as an additive. It could be stored for one year without significant reduction of TAT105. Laboratory-scale composting of swine feces was conducted by mixing the additive. When the additive, mixed with an equal weight of water one day before use, was added to obtain a TAT105 concentration of above 107 CFU/g of dry matter in the initial material, the ammonia concentration emitted was lower and nitrogen loss was approximately 22% lower in the treatment with the additive than in the control treatment without the additive. The colony formation on an agar medium containing high ammonium could be used for enumeration of TAT105 in the composted materials.
antaRNA: ant colony-based RNA sequence design
Authors: Kleinkauf Robert , Mann Martin , Backofen Rolf
Published: May 2015

Motivation: RNA sequence design is studied at least as long as the classical folding problem. Although for the latter the functional fold of an RNA molecule is to be found, inverse folding tries to identify RNA sequences that fold into a function-specific target structure. In combination with RNA-based biotechnology and synthetic biology, reliable RNA sequence design becomes a crucial step to generate novel biochemical components.

Results: In this article, the computational tool antaRNA is presented. It is capable of compiling RNA sequences for a given structure that comply in addition with an adjustable full range objective GC-content distribution, specific sequence constraints and additional fuzzy structure constraints. antaRNA applies ant colony optimization meta-heuristics and its superior performance is shown on a biological datasets.

Availability and implementation:  http://www.bioinf.uni-freiburg.de/Software/antaRNA

Contact:  backofen@informatik.uni-freiburg.de

Supplementary information: Supplementary data are available at Bioinformatics online.
Lessons from a career in fisheries science‡
Authors: Anderson Emory D.
Published: May 2015

This article summarizes some of my accomplishments during a 45-year career in fisheries science that ranged from conducting fish stock assessments, working for an international marine science organization, and managing a variety of scientific projects and activities, to finally serving as a scientific editor. In doing so, I have tried to focus on lessons learned. Starting my working life as a high-school math teacher, I soon opted for a different career, returned to the university, and received a PhD in fisheries biology. The first 15 years of my career were at the Woods Hole Laboratory of the National Marine Fisheries Service (NMFS) doing fish stock assessments, where my main interest was Atlantic mackerel (Scomber scombrus). Until the USA declared a 200-mile Exclusive Economic Zone (EEZ) in early 1977, the focal point of my work was the International Commission for the Northwest Atlantic Fisheries (ICNAF). Lasting friendships with scientists from other countries developed during the ICNAF meetings and continued for years thereafter, some to the present day. During 1977–1985, my assessment activities were confined to domestic fisheries and interactions with regional fishery management councils, where I found that a cooperative attitude and the use of non-technical language made a positive impression and helped build trust. Involvement in ICES assessment working groups led, in 1985, to being appointed Statistician in the ICES Secretariat in Copenhagen and the start of an 8-year life in the international community that culminated in becoming General Secretary. Some major changes in ICES in which I was intimately involved are discussed. After my return to the USA in 1994, my career included managing a variety of activities and projects in Woods Hole and at NOAA/NMFS headquarters in Silver Spring, MD (where I was NMFS liaison to the National Sea Grant Office), finally concluding, after my retirement from NMFS in 2004, with continued engagement in fisheries science as an editor for ICES. Having benefited from experiences in science and administration and the lessons learned therein, it is a pleasure, via this article, to offer advice to young scientists contemplating potential paths to pursue in their careers.
Selling, Sharing, and Everything In Between: The Hybrid Economies of Collaborative Networks
Authors: Scaraboto Daiane
Published: May 2015

Recent consumer research has examined contexts where market-based exchange, gift-giving, sharing, and other modes of exchange occur simultaneously and obey several intersecting logics, but consumer research has not conceptualized these so-called hybrid economic forms nor explained how these hybrids are shaped and sustained. Using ethnographic and netnographic data from the collaborative network of geocaching, this study explains the emergence of hybrid economies. Performativity theory is mobilized to demonstrate that the hybrid status of these economies is constantly under threat of destabilization by the struggle between competing performativities of market and nonmarket modes of exchange. Despite latent tension between competing performativities, the hybrid economy is sustained through consumer–producer engagements in collaborative consumption and production, the creation of zones of indeterminacy, and the enactment of tournaments of value that dissipate controversies around hybrid transactions. Implications are drawn for consumer research on the interplay between market and nonmarket economies.
Nuclear cardiology (PET and SPECT)—basic principles
Authors: Bengel Frank M. , Rimoldi Ornella , Camici Paolo G.
Published: May 2015

Historically, radionuclide imaging has been the key to success and widespread clinical application of non-invasive techniques for detection of myocardial ischaemia. Today, the use of myocardial perfusion single photon emission computed tomography (SPECT) for the diagnostic and prognostic workup of coronary artery disease is supported by a very large body of evidence. Positron emission tomography (PET) as an advanced, quantitative technique is increasingly penetrating the clinical arena. And the field is responding to recent trends by adopting new technology and algorithms for reduction of radiation exposure and by developing a toolbox for targeted molecular imaging of key biologic mechanisms involved in heart disease and therapy response. By this, nuclear cardiology will continue to serve as a role model for the success of functional imaging in heart disease. This chapter gives an overview over the basic technology, including novel methodologic developments.
New developments in echocardiography/advanced echocardiography
Authors: Gianstefani Silvia , Voigt Jens-Uwe , Monaghan Mark J.
Published: May 2015

The first part of this chapter illustrates how real-time three-dimensional echocardiography (3DE) has significantly improved and expanded the diagnostic efficacy of echocardiography providing anatomical and functional visualization of cardiac structures. The reader is introduced to the different applications of 3DE, to the different acquisition and display techniques of a 3D datasets and to the main artefacts which can possibly occur. The second part covers two-dimensional echocardiographic (2DE) and 3DE techniques for the assessment of global and regional myocardial function, its different parameters with typical findings and normal values. Clinical applications of the different techniques are explained focusing on the assessment of diastolic function, global systolic function, regional systolic function and dyssynchrony. Speckle tracking and Tissue Doppler are illustrated and their advantages and disadvantages discussed. Concise and practical information are provided to the reader to better understand and improve data acquisition, post-processing and data interpretation.
Hybrid imaging: combination of PET, SPECT, CT, and MRI
Authors: Knuuti Juhani , Kaufmann Philipp A.
Published: May 2015

Hybrid scanners combining PET or SPECT with high resolution multi-detector CT are becoming the standard for almost all commercially available nuclear imaging systems. In addition, the newest generation of scanners offers combination of PET with MRI. Hybrid scanners offer the ability to assess the anatomy of the heart and coronary arteries, and the functional evaluation either at stress (for assessment of induced ischaemia), or at rest (for viability) in association with the left ventricular systolic function. Therefore, combining functional information with anatomy by using hybrid systems is appealing.
Mitral valve regurgitation
Authors: Lancellotti Patrizio , Magne Julien
Published: May 2015

Mitral regurgitation is increasingly prevalent. Doppler echocardiography not only detects the presence of regurgitation but also permits to understand mechanisms of regurgitation, quantification of its severity, and repercussions. The present chapter aims to provide clues for the assessment of mitral regurgitation using multi-modality imaging.
Tricuspid and pulmonary valve disease
Authors: Popescu Bogdan A. , Gurzun Maria Magdalena , Ginghina Carmen
Published: May 2015

The clinical and prognostic importance of tricuspid and pulmonary valve disease is increasingly recognized. Imaging techniques represent the current gold-standard of assessment in this setting. Therefore, the proper use of imaging in evaluating tricuspid and pulmonary valve structure and function is of great interest for the best management. This chapter describes the anatomy of the right heart valves, the relative role of each imaging technique in evaluating valvular dysfunction and their consequences, and the main modalities employed in the clinical setting in both stenotic and in regurgitant lesions. It also discusses the contribution of each technique in clinical decision-making. Echocardiography remains the main imaging method, usually able to provide all the information needed for patient care. Cardiac magnetic resonance provides a more accurate evaluation of right ventricular size and function, and may be used for both diagnosis and follow-up. Multi-slice computed tomography has a very good spatial resolution, useful in selected cases, but the radiation involved represents a limitation.
Cardiovascular imaging in percutaneous valve therapy
Authors: Canna Giovanni La , Munoz Daniel Rodriguez
Published: May 2015

Valvular heart disease (VHD) is an important cause of morbidity and mortality with an age-related epidemiologic burden. Aortic stenosis and mitral regurgitation are the more prevalent VHDs in patients with native valve disease. Although surgical treatment provides satisfactory outcome, many patients are denied surgery because of the high estimated operative risk and multiple comorbidities. Recently, percutaneous valve therapy has opened a new pathway for VHD, especially in high-risk patients. Multi-modality imaging plays an important role in selecting patients for percutaneous valve procedures, as well as intra-procedural monitoring and follow-up.
CMR and detection of coronary artery disease
Authors: Nagel Eike , Schwitter Juerg , Plein Sven
Published: May 2015

Two principal cardiovascular magnetic resonance (CMR) methods are available for the detection of coronary artery disease (CAD): dobutamine-CMR and perfusion-CMR. With dobutamine-CMR, inducible wall motion abnormalities induced by pharmacological stress are detected as a sign of ischaemia, analogous to dobutamine-stress echocardiography. Dobutamine-CMR provides reliably high image quality regardless of body habitus and is therefore an alternative for patients with insufficient echocardiographic image quality. The principle of perfusion-CMR is most comparable to nuclear myocardial perfusion methods and delineates lack of perfusion reserve during vasodilator-induced hyperaemia in myocardium subtended by coronary arteries with flow-limiting stenoses. Both dobutamine and perfusion-CMR provide high diagnostic accuracy and prognostically relevant information, with recent single and multi-centre studies demonstrating that perfusion-CMR is non-inferior to nuclear imaging for CAD detection. In addition, CMR offers complementary methods for the detection of myocardial scar and assessment of viability. Late gadolinium enhancement (LGE) CMR delineates scar or fibrosis with high tissue contrast and spatial resolution. Low-dose dobutamine-CMR provides information about contractile reserve and the potential for functional recovery of dysfunctional myocardium. CMR thus offers a comprehensive set of methods for the detection of disease, prognostication and planning of management in patients with known or suspected CAD.
Echocardiography to assess viability
Authors: Senior Roxy , Dias Nuno Cortez , Shah Benoy N. , Pinto Fausto J
Published: May 2015

The reduction in mortality from acute myocardial infarction in developed nations has resulted in a larger number of survivors with consequent left ventricular dysfunction. Management of these patients with ischaemic cardiomyopathy remains a challenge, since prognosis remains poor—and worse than that of non-ischaemic heart failure—despite appropriate use of implantable cardioverter-defibrillator and resynchronization devices. A large body of evidence accrued over the past three decades—predominantly retrospective in nature and observational in design—suggests that revascularization is superior to optimal medical therapy in patients with a large amount of ‘viable’ myocardium (i.e. dysfunctional myocardium at rest, which is not scar tissue and thus has, in theory, the potential to recover function after treatment). The global cardiology community has embraced this dogma, as many units worldwide place great emphasis upon the results of imaging tests (which aim to determine the presence and extent of myocardial ‘viability’) in guiding management strategy—specifically, whether to offer or deny a patient revascularization. This practice has been challenged recently by the results of the STICH trials, which suggested both lack of benefit from revascularization and no incremental benefit from viability testing. A number of imaging techniques exist for identifying viable myocardium. This chapter reviews the echocardiographic modalities that can be used to identify viable myocardium and compare these with other available techniques. We also analyse the results of the main STICH trial and the STICH viability sub-study and suggest an algorithm for integration of multi-modality imaging in the evaluation of myocardial viability.
Hypertrophic cardiomyopathy
Authors: Flachskampf Frank A. , Bruder Oliver , Beyer Ruxandra , Nihoyannopoulos Petros
Published: May 2015

Hypertrophic cardiomyopathy is usually diagnosed by echocardiography. Typical signs are an increase in left ventricular wall thickness and mass not explained by other conditions leading to hypertrophy (e.g. hypertension). The distribution of hypertrophy varies widely and may be diffuse or localized, but most frequently involves a massively thickened ventricular septum. In a subset of patients, left ventricular outflow tract or mid-ventricular obstruction is present, detectable by Doppler analysis and by morphologic signs such as systolic anterior motion of the mitral valve. Tissue Doppler and deformation analysis, which show decreased longitudinal myocardial velocities and deformation parameters in the affected walls, enhances the diagnostic accuracy and may allow the detection of subclinical disease. Alternatively and additionally, cardiovascular magnetic resonance imaging provides excellent morphologic delineation of the abnormal morphology in hypertrophic cardiomyopathy, and by visualizing areas of intramyocardial fibrosis due to late enhancement after gadolinium contrast can contribute to risk stratification for malignant arrhythmias.
Overdiagnosis in Psychiatry
Authors: Paris Joel
Published: May 2015

As one of the few resources to thoroughly examine the critical problem of over-diagnosis in psychiatry today, this title covers how over-diagnosis in psychiatric practice may lead to over-treatment. It considers the complications of the DSM-5 classification system, with particular reference to major depression, bipolar disorder, Post-traumatic Stress Disorder (PTSD), and Attention-Deficit Hyperactivity Disorder (ADHD). While each of these conditions have given rise to diagnostic fads and epidemics, the classification of mental disorders remains provisional without any biomarkers for mental disorders. It then covers the importance of conservative diagnoses, recognizing that normal variants are not necessarily disorder, and that in many cases, under-, rather than over-diagnosing may be best practice.
The DSM and Its Discontents
Authors: Paris Joel
Published: May 2015

DSM-5 aimed to provide psychiatry with a more scientifically based classification system, based on neurobiology. However, this goal could not be achieved in the absence of more convincing data. This is why the manual is not dramatically different from its predecessors. Attempts to make diagnoses dimensional, to put them in spectra, and to relate them to changes in the brain are premature at our present state of knowledge. While the National Institute of Mental Health has developed its own system. However, we do not have the data at this point to develop a classification that would be consistent with neurobiology. Moreover, diagnosis need not reduce complex mental phenomena to a cellular or endophenotypic level.
Overdiagnosis and Over-Treatment
Authors: Paris Joel
Published: May 2015

Current neurobiological models of mental illness, accompanied by an increased use of drugs to control symptoms, tend to favor overdiagnosis. This trend has been supported by DSM-5. Yet it is often forgotten that diagnostic manuals are not a guide to treatment. The pigeon-holing of patients with a wide range of psychological symptoms into categories (such as bipolar disorder or ADHD) has been used to justify pharmacological interventions that have been empirically tested in clinical populations who have classical forms of mental disorder, as opposed to falling within spectra. The result is that treatments for this wider range of patients may or may not be valid.
Bipolar Disorders
Authors: Paris Joel
Published: May 2015

The overdiagnosis of bipolar disorders is one of the most troubling problems affecting contemporary practice. The concept of a bipolar spectrum has led to unnecessary pharmacological interventions in patients who do not have the classical symptoms of bipolarity. There has also been a failure to distinguish bipolarity from affective instability, which is often a feature of personality disorders. Patients who do not respond to antidepressants may be mistakenly prescribed mood stabilizers. The overdiagnosis of bipolar disorders has also affected child psychiatry, in that children who have severe behavior disorders and irritiability are seen as falling within the spectrum.
Personality and Personality Disorder
Authors: Paris Joel
Published: May 2015

Personality disorders are difficult to distinguish from normal variations in personality traits. They tend to be under-diagnosed because of a focus on overt symptoms such as dépression or anxiety rather than on psychosocial or interpersonal dysfunction. There is also a danger of overdiagnosis, which has emerged from epidemiological research in which criteria have been too broad. The DSM-5 definitions of personality disorder are rather complex, both in their traditional form, and in an altérative model now included in Section III of the manual: many clinicians find them difficult to apply. There is also a tendency to favor diagnoses of mood disorders that are believed to be susceptible to psychopharmacological intervention.
How Do We Know What Is Normal?
Authors: Paris Joel
Published: May 2015

Medicine and psychiatry have not developed models that sufficiently acknowledge normal variations, and how these may relate to psychopathology. While normality can be defined in different ways, it is important to realize that people respond to life circumstances in ways that closely resemble mental disorders. The difference is that normal responses are either more transient, or reversible if circumstances change. The failure to recognize normative distress a leads to over-medicalization and over-treatment.
Jails and prisons
Authors: Dvoskin Joel , Brown Melody C.
Published: May 2015

There are many similarities between prisons and jails, especially in regard to the constitutional standard for mental health services. However, the differences are important to recognize in assuring that the unique needs of each kind of institution are met. Historically, jails have been used to hold defendants for trial, and to confine prisoners who have been sentenced for misdemeanors, typically for sentences of less than one year. In contrast, prisons are managed by state or federal governments and used for longer-term confinement of convicted felons, who generally serve sentences of one year or longer. Predominant among these differences is the very high degree of turnover in jail populations, resulting in dramatic increases in acuity of mental illness and substance misuse, significantly increased risk of suicide, and the increases in workload due to the much higher percentage of initial assessments. In contrast, prison mental health services are more often faced with the realities of serious and persistent mental illnesses, and the hopelessness that can come after years of incarceration and in the face of very long sentences. While prison mental health clinicians have more time with which to work, they also face significantly greater expectations for treatment that goes beyond crisis response and psychotropic medication. Distinctions between prisons and jails in terms of service delivery and the kinds of treatment challenges that exist in the long-term management of prisoners with serious mental illness are discussed.
Working inside the walls
Authors: Gage Bruce C.
Published: May 2015

This chapter is a pragmatic discussion of the experience of working as a psychiatrist in correctional settings, whether jails or prisons. To work inside the walls, the psychiatrist must come to terms with the realities of the correctional setting in order to be secure, satisfied with the work, and clinically effective. There is no monolithic correctional culture. Each system and facility has its own unique culture and has evolved in some degree of isolation, emphasizing different philosophical approaches to the correctional mission and to criminal causation. This chapter examines the context in which clinical work is embedded: physical environment and security, correctional culture, personal safety, typical stressors, and individual liability. It is clearly not for everybody but the rewards can be tremendous. The quality of care in many facilities, especially prisons, is superior to care in the community. The clinical problems are unendingly fascinating. And, despite its downsides, having a setting with limited access to drugs that provides food, clothing, shelter, and medical care can allow a degree of patient improvement that may be difficult to realize in the community. Opportunities for creativity in treatment and program development are unparalleled. In many ways, correctional psychiatry is poised to lead the way in the treatment of some of the most ill and behaviorally disordered members of society.