bluuebunny/crossref_metadata_2025 huggingface dataset:
Energy spectra of finite temperature superfluid helium-4 turbulence
Authors: Kivotides Demosthenes
Published: October 2014

A mesoscopic model of finite temperature superfluid helium-4 based on coupled Langevin-Navier-Stokes dynamics is proposed. Drawing upon scaling arguments and available numerical results, a numerical method for designing well resolved, mesoscopic calculations of finite temperature superfluid turbulence is developed. The application of model and numerical method to the problem of fully developed turbulence decay in helium II, indicates that the spectral structure of normal-fluid and superfluid turbulence is significantly more complex than that of turbulence in simple-fluids. Analysis based on a forced flow of helium-4 at 1.3 K, where viscous dissipation in the normal-fluid is compensated by the Lundgren force, indicate three scaling regimes in the normal-fluid, that include the inertial, low wavenumber, Kolmogorov k−5/3 regime, a sub-turbulence, low Reynolds number, fluctuating k−2.2 regime, and an intermediate, viscous k−6 range that connects the two. The k−2.2 regime is due to normal-fluid forcing by superfluid vortices at high wavenumbers. There are also three scaling regimes in the superfluid, that include a k−3 range that corresponds to the growth of superfluid vortex instabilities due to mutual-friction action, and an adjacent, low wavenumber, k−5/3 regime that emerges during the termination of this growth, as superfluid vortices agglomerate between intense normal-fluid vorticity regions, and weakly polarized bundles are formed. There is also evidence of a high wavenumber k−1 range that corresponds to the probing of individual-vortex velocity fields. The Kelvin waves cascade (the main dynamical effect in zero temperature superfluids) appears to be damped at the intervortex space scale.
Nanodot formation induced by femtosecond laser irradiation
Authors: Abere M. J. , Chen C. , Rittman D. R. , Kang M. , Goldman R. S. , Phillips J. D. , Torralva B. , Yalisove S. M.
Published: October 2014

The femtosecond laser generation of ZnSe nanoscale features on ZnSe surfaces was studied. Irradiation with multiple exposures produces 10–100 nm agglomerations of nanocrystalline ZnSe while retaining the original single crystal structure of the underlying material. The structure of these nanodots was verified using a combination of scanning transmission electron microscopy, scanning electron microscopy, and atomic force microscopy. The nanodots continue to grow hours after irradiation through a combination of bulk and surface diffusion. We suggest that in nanodot formation the result of ultrafast laser induced point defect formation is more than an order of magnitude below the ZnSe ultrafast melt threshold fluence. This unique mechanism of point defect injection will be discussed.
Room temperature persistent photoconductivity in p-PbTe and p-PbTe:BaF2
Authors: de Castro S. , Soares D. A. W. , Peres M. L. , Rappl P. H. O. , Abramof E.
Published: October 2014

We investigated the persistent photoconductivity effect observed in p-PbTe:BaF2 and undoped p-PbTe films in the temperature range of T = 100–300 K. It was observed that the PPC effect scales with temperature and that there is a transition in the relaxation time behavior around ∼150 K. We found that the transition is caused by the particular dynamics of the hole carries between the energy barriers that characterize the traps originated from disorder present in the samples. The analysis was performed by comparing the theory of the random potential with the experimental data and revealed the presence of both random local potential fluctuations and localized states, which can be attributed to the presence of disorder due BaF2 doping and Te vacancies.
Stable and metastable Si negative-U centers in AlGaN and AlN
Authors: Trinh Xuan Thang , Nilsson Daniel , Ivanov Ivan G. , Janzén Erik , Kakanakova-Georgieva Anelia , Son Nguyen Tien
Published: October 2014

Electron paramagnetic resonance studies of Si-doped AlxGa1−xN (0.79 ≤ x ≤ 1.0) reveal two Si negative-U (or DX) centers, which can be separately observed for x ≥ 0.84. We found that for the stable DX center, the energy |EDX| of the negatively charged state DX−, which is also considered as the donor activation energy, abruptly increases with Al content for x ∼ 0.83–1.0 approaching ∼240 meV in AlN, whereas EDX remains to be close to the neutral charge state Ed for the metastable DX center (∼11 meV below Ed in AlN).
Diagnosis of bubble evolution in laser-wakefield acceleration via angular distributions of betatron x-rays
Authors: Ma Y. , Chen L. M. , Hafz N. A. M. , Li D. Z. , Huang K. , Yan W. C. , Dunn J. , Sheng Z. M. , Zhang J.
Published: October 2014

We present an indirect method to diagnose the electron beam behaviors and bubble dynamic evolution in a laser-wakefield accelerator. Four kinds of typical bubble dynamic evolution and, hence, electron beam behaviors observed in Particle-In-Cell simulations are identified correspondingly by simultaneous measurement of distinct angular distributions of the betatron radiation and electron beam energy spectra in experiment. The reconstruction of the bubble evolution may shed light on finding an effective way to better generate high-quality electron beams and enhanced betatron X-rays.
Single-shot hyperspectral coherent Raman planar imaging in the range 0–4200 cm−1
Authors: Bohlin Alexis , Kliewer Christopher J.
Published: October 2014

We propose a technique for ultrabroadband planar coherent Raman spectroscopy that enables wideband chemically selective mapping of molecular partition functions in the gas-phase within a single-laser-shot. A spectral region spanning 0–4200 cm−1 is excited simultaneously, in principle allowing for coherent planar imaging of most all fundamental Raman-active modes. This unique instantaneous and spatially correlated assessment enables multiplexed studies of transient dynamical systems in a two-dimensional (2D) field. Here, we demonstrate single-laser-shot high temperature diagnostics of H2, with spatially resolved 2D measurement of transitions of both the pure-rotational H2 S-branch and the vibrational H2 Q-branch, analyzing the temperature contour of a reacting fuel-species as it evolves at a flame-front.
Cascade type-I quantum well diode lasers emitting 960 mW near 3 μm
Authors: Shterengas Leon , Liang Rui , Kipshidze Gela , Hosoda Takashi , Belenky Gregory , Bowman Sherrie S. , Tober Richard L.
Published: October 2014

The cascade pumping scheme reduced the threshold current density of high power type-I quantum well GaSb-based λ ∼ 3 μm diode lasers down to ∼100 A/cm2 at room temperature. Laser heterostructures had single GaInAsSb quantum well gain stages connected in series by means of GaSb/AlSb/InAs tunnel junctions followed by InAs/AlSb electron injectors. Devices with densely stacked two and three gain stages and 100-μm-wide aperture demonstrated peak power conversion efficiency of 16% and continuous wave output power of 960 mW. Corresponding narrow ridge lasers demonstrated above 100 mW of output power. The experiment showed that the bandwidth of the gain and its rate of increase with current depended strongly on the thickness of AlSb layer separating electron injectors from quantum wells. The possible impact of electron injector interfaces and ionized impurities on the carrier scattering and recombination in the active quantum well is discussed.
Rotating Goblet and Talking Profiles: Does a Rotating Goblet Increase the Figural Dominance of Profiles in Rubin's Type of Figure-Ground Reversal Patterns?
Authors: Wake Hiromi , Wake Tenji , Oyama Tadasu
Published: October 2014

We present a novel three-dimensional (3-D) version of Rubin's classical bistable goblet–profiles figure. An actual goblet sculpture was produced and rotated on a turntable in front of a white background. As the goblet rotates about its central axis, small circular asymmetries around the lips and chin region give a clear impression of two white profiles talking to each other. Although the profiles actually correspond to empty space or white background, they are more likely to be perceived as ‘figure’ than the 3-D goblet itself. Four experiments that presented the actual goblet (experiment 1) or two-dimensional (2-D) movies of it (experiments 2–4) were designed to verify these observations. We measured perceptual dominance of profiles as ‘figure’ and rate of reversal as a function of three factors: Motion (static vs rotating), orientation (upright vs inverted), and configuration (face-to-face vs back-to-back). Results for the rotating goblet showed a statistically reliable preference for perceiving the talking profiles as ‘figure’. Deforming the profiles by manipulating the vertex angle of the mouth region produced an inverted U-shaped curve with the peak representing the stimulus condition in which the profiles perception was most remarkable. We discussed a number of 3-D and 2-D figure-ground factors that might apply to this rather complex stimulus situation.
Basics of Statistical Mechanics of Short-Range Interacting Systems
Authors: Campa A. , Dauxois T. , Fanelli D. , Ruffo S.
Published: October 2014

This chapter begins with a rapid introduction to the definition and construction of the statistical ensembles, following the lines that are usually offered in the basics courses on statistical mechanics. The reader is assumed to be already acquainted with thermodynamics and basic statistical mechanics, but the introduction is self-contained. It is then shown that with short-range interactions the ensembles are physically equivalent, even in the presence of phase transitions. This is done by introducing the notions of concave functions, of stable and tempered potentials, and the Legendre-Fenchel transform of thermodynamic functions. The concavity of the entropy is at the basis of ensemble equivalence. Finally, the concepts of microstate and macrostate are analysed; they are very important for the study of ensemble equivalence or inequivalence in long-range systems.
Quantum Long-Range Systems
Authors: Campa A. , Dauxois T. , Fanelli D. , Ruffo S.
Published: October 2014

This chapter opens with the notion of stable interaction in quantum systems, somewhat different from classical systems. It is shown that an unstable classical system can become stable when treated quantum mechanically. The remaining of the chapter is devoted to a brief survey of the main results concerning the stability of Coulomb systems. Explicit evaluations of the total energy show that the exclusion principle is essential for their stability. The final part of the chapter deals with the thermodynamic limit of globally neutral Coulomb systems. The limit exists in spite of the long-range character of the interaction, and contrary to the stability property, the existence of the limit does not require quantum mechanics, being valid also in classical Coulomb systems.
Gravitational Systems
Authors: Campa A. , Dauxois T. , Fanelli D. , Ruffo S.
Published: October 2014

In this Chapter the equilibrium and out-of-equilibrium dynamics of self-gravitating systems is discussed. The case of 1D planar systems is in particular investigated and the equilibrium statistical mechanics solution presented in some details. Long-lived quasi stationary states are found and successfully explained with the Lynden Bell statistical mechanics theory. The problem of structure formation in an expanding Universe is also introduced. The classical Vlasov-Poisson model and the adhesion approximation are recovered starting from relevant general relativity setting. In one dimension an exact event-driven scheme can be implemented which enables one to efficiently track the evolution of the system. Different simulations strategies in 3D are shortly discussed.
Cold Coulomb Systems
Authors: Campa A. , Dauxois T. , Fanelli D. , Ruffo S.
Published: October 2014

In this Chapter the statistical mechanics of charged particles subject to Coulomb interactions is discussed. The relevant physical parameters are introduced which enable one to classify the different systems under inspection. The classification is drawn for the reference case of globally neutral systems, with two species of charges, one positive and the other negative, equal in magnitude. The case of strongly interacting plasma is discussed and the equilibrium properties analyzed in the framework of the Debye-Huckel theory. In the final part of the Chapter, degenerate electron systems and the concept of Wigner crystal are reviewed.
Hot Plasma
Authors: Campa A. , Dauxois T. , Fanelli D. , Ruffo S.
Published: October 2014

In this Chapter a short introduction to the physics of hot plasma is given. The concepts of Debye shielding and quasi-neutrality are in particular discussed. The Vlasov-Maxwell equations are derived following the Klimontovich approach. Working within the collisionless Vlasov picture, the case of electrostatic waves is presented and the phenomenon of linear Landau damping reviewed in some details. The non linear regime of the wave-particles interaction is also briefly analyzed. Explicit reference is made to the collective BGK and Case-van Kampen modes.
Wave–Particles Interaction
Authors: Campa A. , Dauxois T. , Fanelli D. , Ruffo S.
Published: October 2014

In this Chapter an alternative derivation of the self-consistent Vlasov-Maxwell equations for wave-particles interaction is given. The analysis is carried out under a rigorous Hamiltonian framework and targeted to modeling the dynamics of the Free Electron Laser. A universal one dimensional Hamiltonian is eventually recovered which proves of interest in all domains of applications where particles and waves are mutually interacting. The same Hamiltonian is obtained via an heuristic derivation that moves from the concept of Langmuir waves, as introduced in the preceding Chapter. The physics of Free Electron Laser is then discussed and the large deviation method applied to determine the intensity of the laser at equilibrium. The Lynden-Bell theory returns adequate predictions for the average laser intensity and bunching degree in the quasi stationary regime. Finally, the analogies between Free Electron Laser, plasma and Travelling Wave Tubes are discussed.
A minimal model for metabolism-dependent chemotaxis inRhodobacter sphaeroides
Authors: Fan Sisi , Endres Robert G.
Published: October 2014

Chemotaxis is vital cellular movement in response to environmental chemicals. Unlike the canonical chemotactic pathway inEscherichia coli,Rhodobacter sphaeroideshas both transmembrane and cytoplasmic sensory clusters, with the latter possibly interacting with essential components in the electron transport system. However, the effect of the cytoplasmic sensor and the mechanism of signal integration from both sensory clusters remain unclear. Based on a minimal model of the chemotaxis pathway in this species, we show that signal integration at the motor level produces realistic chemotactic behaviour in line with experimental observations. Our model also suggests that the core pathway ofR. sphaeroides, at least its ancestor, may represent a metabolism-dependentselective stoppingstrategy, which alone can steer cells to favourable environments. Our results not only clarify the potential roles of the two sensory clusters but also put in question the current definitions of attractants and repellents.
Molecular mechanisms for microtubule length regulation by kinesin-8 and XMAP215 proteins
Authors: Reese Louis , Melbinger Anna , Frey Erwin
Published: October 2014

The cytoskeleton is regulated by a plethora of enzymes that influence the stability and dynamics of cytoskeletal filaments. How microtubules (MTs) are controlled is of particular importance for mitosis, during which dynamic MTs are responsible for proper segregation of chromosomes. Molecular motors of the kinesin-8 protein family have been shown to depolymerize MTs in a length-dependent manner, and recent experimental and theoretical evidence suggests a possible role for kinesin-8 in the dynamic regulation of MTs. However, so far the detailed molecular mechanisms of how these molecular motors interact with the growing MT tip remain elusive. Here we show that two distinct scenarios for the interactions of kinesin-8 with the MT tip lead to qualitatively different MT dynamics, including accurate length control as well as intermittent dynamics. We give a comprehensive analysis of the regimes where length regulation is possible and characterize how the stationary length depends on the biochemical rates and the bulk concentrations of the various proteins. For a neutral scenario, where MTs grow irrespective of whether the MT tip is occupied by a molecular motor, length regulation is possible only for a narrow range of biochemical rates, and, in particular, limited to small polymerization rates. By contrast, for an inhibition scenario, where the presence of a motor at the MT tip inhibits MT growth, the regime where length regulation is possible is extremely broad and includes high growth rates. These results also apply to situations where a polymerizing enzyme like XMAP215 and kinesin-8 mutually exclude each other from the MT tip. Moreover, we characterize the differences in the stochastic length dynamics between the two scenarios. While for the neutral scenario length is tightly controlled, length dynamics is intermittent for the inhibition scenario and exhibits extended periods of MT growth and shrinkage. On a broader perspective, the set of models established in this work quite generally suggest that mutual exclusion of molecules at the ends of cytoskeletal filaments is an important factor for filament dynamics and regulation.
Crystal structure of 2,5-dimethyl-3-(2-methylphenylsulfonyl)-1-benzofuran
Authors: Choi Hong Dae , Lee Uk
Published: October 2014

The title compound, C17H16O3S, crystallized with two independent molecules (AandB) in the asymmetric unit. The dihedral angle between the benzofuran ring system [r.m.s. deviation of 0.013 (1) forAand 0.009 (1) Å forB] and the 2-methylphenyl ring is 83.88 (5) forAand 86.94 (5)° forB. In the crystal, theBmolecules are linked into a chain along theb-axis direction by C—H...O hydrogen bonds. TheAmolecules are connected on either side of this chain by further C—H...O hydrogen bonds. These chains are linkedviaC—H...π interactions, forming sheets parallel to (100). There are also very weak π–π interactions present [centroid–centroid distance = 3.925 (11) Å] involvingthe 2-methylphenyl rings of neighbouringAandBmolecules.
Crystal structure of 2,2-diphenylhydrazinium chloride
Authors: Paul Amit Kumal , Mukherjee Soma , Stoeckli-Evans Helen
Published: October 2014

In the title compound, C12H13N2+·Cl−, the chloride salt of 1,1′-diphenylhydrazine, the phenyl rings are inclined to one another by 78.63 (17)°. The N—+NH3bond lengths is 1.445 (3) Å, and the N—Cphenylbond lengths are 1.435 (3) and 1.447 (4) Å. In the crystal, molecules are linkedviaN—H...Cl hydrogen bonds, forming chains along [10-1], which enclose two adjacentR42(6) ring motifs. The chains are reinforced by C—H...Cl hydrogen bonds.
Purification, crystallization and preliminary X-ray crystallographic analysis of the flagellar accessory protein FlaH from the methanogenic archaeonMethanocaldococcus jannaschii
Authors: Meshcheryakov Vladimir A. , Yoon Young-Ho , Matsunami Hideyuki , Wolf Matthias
Published: October 2014

The flagellar accessory protein FlaH is thought to be one of the essential components of an archaeal motility system. However, to date biochemical and structural information about this protein has been limited. Here, the crystallization of FlaH from the hyperthermophilic archaeonMethanocaldococcus jannaschiiis reported. Protein crystals were obtained by the vapour-diffusion method. These crystals belonged to space groupP3121, with unit-cell parametersa=b= 131.42,c= 89.35 Å. The initial solution of the FlaH structure has been determined by multiple-wavelength anomalous dispersion phasing using a selenomethionine-derivatized crystal.
Expression, purification, crystallization and preliminary X-ray crystallographic analysis of the extracellular olfactomedin domain of gliomedin
Authors: Han Huijong , Kursula Petri
Published: October 2014

Gliomedin (GLDN) is one of the essential proteins in the development of the nodes of Ranvier in the vertebrate peripheral nervous system. An olfactomedin (OLF) domain is located at the GLDN extracellular C-terminus and is involved in the accumulation of neuronal plasma membrane voltage-gated sodium channels in the nodes by interacting with neurofascin and NrCAM. No structures of OLF domains have previously been reported. Here, the crystallization of the rat GLDN OLF domain, which was expressed in an insect-cell system, is reported. The crystal diffracted to 1.55 Å resolution and belonged to space groupP21, with unit-cell parametersa= 37.5,b= 141.7,c= 46.0 Å, β = 110.6°, and had two molecules in the asymmetric unit.
The structure of rice weevil pectin methylesterase
Authors: Teller David C. , Behnke Craig A. , Pappan Kirk , Shen Zicheng , Reese John C. , Reeck Gerald R. , Stenkamp Ronald E.
Published: October 2014

Rice weevils (Sitophilus oryzae) use a pectin methylesterase (EC 3.1.1.11), along with other enzymes, to digest cell walls in cereal grains. The enzyme is a right-handed β-helix protein, but is circularly permuted relative to plant and bacterial pectin methylesterases, as shown by the crystal structure determination reported here. This is the first structure of an animal pectin methylesterase. Diffraction data were collected to 1.8 Å resolution some time ago for this crystal form, but structure solution required the use of molecular-replacement techniques that have been developed and similar structures that have been deposited in the last 15 years. Comparison of the structure of the rice weevil pectin methylesterase with that fromDickeya dandantii(formerlyErwinia chrysanthemi) indicates that the reaction mechanisms are the same for the insect, plant and bacterial pectin methylesterases. The similarity of the structure of the rice weevil enzyme to theEscherichia colilipoprotein YbhC suggests that the evolutionary origin of the rice weevil enzyme was a bacterial lipoprotein, the gene for which was transferred to a primitive ancestor of modern weevils and other Curculionidae. Structural comparison of the rice weevil pectin methylesterase with plant and bacterial enzymes demonstrates that the rice weevil protein is circularly permuted relative to the plant and bacterial molecules.
Production, crystallization and preliminary X-ray diffraction of the Gαs α-helical domain in complex with a nanobody
Authors: Triest Sarah , Wohlkönig Alexandre , Pardon Els , Steyaert Jan
Published: October 2014

GPCR–G-protein complexes are one of the most important components of cell-signalling cascades. Extracellular signals are sensed by membrane-associated G-protein-coupled receptors (GPCRs) and transducedviaG proteins towards intracellular effector molecules. Structural studies of these transient complexes are crucial to understand the molecular details of these interactions. Although a nucleotide-free GPCR–G-protein complex is stable, it is not an ideal sample for crystallization owing to the intrinsic mobility of the Gαs α-helical domain (AHD). To stabilize GPCR–G-protein complexes in a nucleotide-free form, nanobodies were selected that target the flexible GαsAHD. One of these nanobodies, CA9177, was co-crystallized with the GαsAHD. Initial crystals were obtained using the sitting-drop method in a sparse-matrix screen and further optimized. The crystals diffracted to 1.59 Å resolution and belonged to the monoclinic space groupP21, with unit-cell parametersa= 44.07,b= 52.55,c= 52.66 Å, α = 90.00, β = 107.89, γ = 90.00°. The structure of this specific nanobody reveals its binding epitope on GαsAHD and will help to determine whether this nanobody could be used as crystallization chaperone for GPCR–G-protein complexes.
From smart specialisation to smart specialisation policy
Authors: Foray Dominique
Published: October 2014

Purpose

– The purpose of this paper is to focus on the distinction between smart specialisation and smart specialisation policy and it studies under what conditions a smart specialisation policy is necessary.

Design/methodology/approach

– A conceptual framework is built based on historical evidence of successful dynamics of structural changes at regional level qualified as “smart specialisation”. The identification of market and coordination failures that are likely to impede the occurrence of spontaneous process of smart specialisation makes a good case for a smart specialisation policy.

Findings

– The paper highlights important design principles for the policy process that should help to minimise potential risks of policy failures and policy capture.

Research limitations/implications

– The paper does assess the effect of smart specialisation on innovation and growth at regional level because it is too early to observe and measure effects. The paper confines itself to conjectures about the effects of such a policy.

Practical implications

– The paper makes recommendations and explains some of the practicalities about the implementation of the policy at regional level.

Originality/value

– The paper is one of the first dealing with the topic of smart specialisation policy.
Is the French sociology of organisations specifically French?
Authors: Frederic Livian Yves
Published: October 2014

Purpose

– The purpose of this paper is to study the contribution of French sociology of organisations (mainly represented by M. Crozier, E. Friedberg and J.D. Reynaud) to the knowledge of organisations in the French context, specially through the “bureaucratic phenomenon”.

Design/methodology/approach

– The author shows that the work has provided a relevant picture of some of the main characteristics of a “French way of organising”, but shows in a second part that French specificities are only a part of the authors’ scientific project, and discusses some of the reasons why it did not get a large international recognition in the English-speaking literature.

Findings

– The article provides a summary of the analysis and a discussion of its relevance to the French context today. It opens a reflection about the question as to whether a sociological school based on field studies can be used outside of its original context of conception.

Research limitations/implications

– The author does not have the ambition of an exhaustive overview of the international impact of this school.

Practical implications

– The author aims at a reevaluation of the contribution, for English-speaking academics, and at a development of the thinking about the use of the “strategic analysis” model.

Originality/value

– An examination of the today relevance of the “bureaucratic” model in France, and a better knowledge of the interest of this school outside France.
Broadcasting, reacting, engaging – three strategies for CSR communication in Twitter
Authors: Etter Michael
Published: October 2014

Purpose

– Symmetric communication and relationship building are core principles of public relations, which have been highlighted for CSR communication. The purpose of this paper is to develop three different communication strategies for CSR communication in Twitter, of which each contributes differently to the ideals of symmetric communication and relationship building. The framework is then applied to analyze how companies use the micro-blogging service Twitter for CSR communication.

Design/methodology/approach

– Social network analysis is used to identify the 30 most central corporate accounts in a CSR Twitter network.

Findings

– From the social network analysis 40,000 tweets are extracted and manually coded. Anova is applied to investigate differences in the weighting of CSR topics between the different strategies.

Originality/value

– So far not much is known about how social media, such as Twitter, contribute to the core principles of public relations, if companies use social media to foster symmetric communication and relationship management, or which CSR topics they address.
Broadband Internet adoption challenge
Authors: Miri Lavassani Kayvan , Movahedi Bahar , Parry Glenn
Published: October 2014

Purpose

– This paper aims to investigate empirically how broadband has been implemented at the business level and what are the potential adoption benchmarks. Several recent studies have called for the development of frameworks of broadband adoption, particularly at the business level, to help policy makers, communities and businesses with their strategic decision-making process.

Design/methodology/approach

– This paper opens the discussion by presenting concerns and challenges of Internet adoption. Internet adoption is viewed as the current challenge facing businesses, communities and governments. Exploratory factor analysis (EFA) and confirmatory factor analysis (CFA) techniques are used to create, analyze and develop Internet adoption models.

Findings

– Based on the Internet usage data from a number of states across the USA, measurement models are developed using EFA and CFA. The findings indicate that for our sample, a three-factor model is the most appropriate for the representation of Internet adoption in the tourism sector, while a five-factor model can best describe Internet adoption in the sample of manufacturing organizations.

Research limitations/implications

– The availability of data on Internet usage at the business/organizational level is one of the main constraints. Industry/community-specific data can also provide valuable insights about the Internet adoption and support the development of industry/community-specific adoption models.

Practical implications

– The findings and the employed research method can be used by businesses, communities and government managers and policy makers as benchmarks to examine broadband adoption based on gap-opportunity criteria.

Originality/value

– This is the first study that provides Internet adoption models based on an empirical study at the business level. The benefits of broadband Internet have been investigated by many researchers in the past decade. There seems to be a consensus among practitioners and scholars about the role of broadband Internet in gaining competitive advantage. However, there have not been any previous studies that investigate how broadband has been implemented and what the potential adoption benchmarks at the business level are.
Factors affecting longitudinal trajectories of plasma sphingomyelins: the Baltimore Longitudinal Study of Aging
Authors: Mielke Michelle M. , Bandaru Veera Venkata Ratnam , Han Dingfen , An Yang , Resnick Susan M. , Ferrucci Luigi , Haughey Norman J.
Published: October 2014

Sphingomyelin metabolism has been linked to several diseases and to longevity. However, few epidemiological studies have quantified individual plasma sphingomyelin species (identified by acyl‐chain length and saturation) or their relationship between demographic factors and disease processes. In this study, we determined plasma concentrations of distinct sphingomyelin species in 992 individuals, aged 55 and older, enrolled in the Baltimore Longitudinal Study of Aging. Participants were followed, with serial measures, up to 6 visits and 38 years (3972 total samples). Quantitative analyses were performed on a high‐performance liquid chromatography‐coupled electrospray ionization tandem mass spectrometer. Linear mixed models were used to assess variation in specific sphingomyelin species and associations with demographics, diseases, medications or lifestyle factors, and plasma cholesterol and triglyceride levels. We found that most sphingomyelin species increased with age. Women had higher plasma levels of all sphingomyelin species and showed steeper trajectories of age‐related increases compared to men. African Americans also showed higher circulating sphingomyelin concentrations compared to Caucasians. Diabetes, smoking, and plasma triglycerides were associated with lower levels of many sphingomyelins and dihydrosphingomyelins. Notably, these associations showed specificity to sphingomyelin acyl‐chain length and saturation. These results demonstrate that longitudinal changes in circulating sphingomyelin levels are influenced by age, sex, race, lifestyle factors, and diseases. It will be important to further establish the intra‐individual age‐ and sex‐specific changes in each sphingomyelin species in relation to disease onset and progression.
Toll‐like Receptor‐Mediated Responses by Placental Hofbauer Cells (HBCs): A Potential Pro‐Inflammatory Role for Fetal M2 Macrophages
Authors: Young Omar M. , Tang Zhonghua , Niven‐Fairchild Tracy , Tadesse Serkalem , Krikun Graciela , Norwitz Errol R. , Mor Gil , Abrahams Vikki M. , Guller Seth
Published: October 2014

Problem

Microbial‐driven responses in placenta are linked with adverse pregnancy outcomes. The role of Toll‐like receptor (TLR) function in Hofbauer cells (HBCs) and fetal macrophages of the placental villous core remains understudied.

Method of Study

Flow cytometry and immunohistochemistry (IHC) were used to establish the phenotype of HBCs. Regulation of cytokine secretion in response to treatment with TLR agonists and expression levels of TLRs and co‐activators were compared in HBCs, placental fibroblasts (FIBs), and human umbilical vein endothelial cells (HUVECs) using ELISA and qPCR.

Results

Although flow cytometry and IHC revealed HBCs to be M2 (anti‐inflammatory) macrophages, LPS and polyinosinic: polycytidylic acid [poly (I:C)] treatments markedly enhanced IL‐6 secretion by HBCs, and expression of TLR‐2, TLR‐3, TLR‐4, CD14, and MD‐2 was the highest in HBCs.

Conclusion

These results indicate that although HBCs are M2 macrophages, inflammatory responses are induced through TLR‐3 and TLR‐4 in this cell type, suggesting a role in microbial‐driven placental/fetal inflammation.
Spatial and Temporal Patterns of Frugivorous Hornbill Movements in Central Africa and their Implications for Rain Forest Conservation
Authors: Chasar Anthony , Harrigan Ryan J. , Holbrook Kimberly M. , Dietsch Thomas V. , Fuller Trevon L. , Wikelski Martin , Smith Thomas B.
Published: October 2014

Tropical forest conservation and restoration require an understanding of the movements and habitat preferences of important seed dispersers. With forests now being altered at an unprecedented rate, avian frugivores are becoming increasingly vital for forest regeneration. Seed movement, however, is highly dependent on the behavioral characteristics of their dispersers. Here, we examined the movements, habitat preferences, and range sizes of two African frugivores: the Black‐casqued (Ceratogymna atrata) and the White‐thighed (Bycanistes albotibialis) Hornbill, in the lowland rain forests of southern Cameroon. Using satellite transmitters, we tracked eight hornbills for 3 yr to characterize their movements and relate them to environmental landscape features. Hornbill movements differed significantly, with B. albotibialis ranging over larger areas (mean = 20,274 ha) than C. atrata (mean = 5604 ha), and females of both species covering over 15 times the area of males. Evidence suggests that movements are irruptive during particular periods, perhaps driven by low resource availability. In addition, hornbills often returned to the same localities within a year, although movements were not characterized as migratory. Both species displayed significant differences in habitat preference, with B. albotibialis utilizing disturbed habitat more frequently than C. atrata (t = −22.04, P = 2.2 × 10−16). Major roads were found to act as barriers for C. atrata, but not for B. albotibialis. The ability of both hornbill species to move large distances suggests hornbills will play a vital role in the maintenance and regeneration of rain forests in Central Africa as forest fragmentation increases and terrestrial vertebrates decline in numbers.
Impacts of Vegetation and Precipitation on Throughfall Heterogeneity in a Tropical Pre‐Montane Transitional Cloud Forest
Authors: Teale Natalie G. , Mahan Hayden , Bleakney Sarah , Berger Amélie , Shibley Nicole , Frauenfeld Oliver W. , Quiring Steven M. , Rapp Anita D. , Roark E. Brendan , Washington‐Allen Robert
Published: October 2014

Precipitation throughfall (TF) plays an important role in the water balance of tropical forests. This study used 164 gauges to quantify precipitation andTFvariability in a tropical pre‐montane transitional cloud forest on the Caribbean slope of the Cordillera Tilarán, Costa Rica, to identify the ecological and meteorological drivers of this variability. DailyTFmeasurements were taken from 28 June to 17 July 2012 and 12 June to 16 July 2013, for a total of 39 precipitation events. The total meanTFwas 87.9 percent andTFat individual gauges ranged from 22.7 percent to 245.7 percent. Leaf area index (LAI) was calculated above each gauge using hemispheric photography for a mean study‐siteLAIof 7.7. There was no statistically significant relationship betweenLAIandTF. However, the amount ofTFwas positively correlated with precipitation intensity, while the variability ofTFwas negatively correlated with precipitation intensity. Our calculations indicate that at least 61 gauges are required to obtain meanTFestimates with less than 5 percent error. This study demonstrates thatTFis highly spatially heterogeneous due to multiple compounding effects.
An evidence‐based approach to the management of snoring in adults
Authors: Al‐Hussaini A. , Berry S.
Published: October 2014

Background

Snoring is frequently encountered by the otolaryngologist. Given its significant impact on quality of life and that it is a symptom of sleep‐related breathing disorders, diagnosis and treatment are of major importance. In particular, the diagnosis should aim to distinguish between simple snoring and obstructive sleep apnoea. This article aims to provide a systematic, concise and evidence‐based method of managing the adult patient with snoring.

Method

This review was based on a literature search last undertaken on 30 June 2014. The MEDLINE, EMBASE and Cochrane databases were searched using the subject headings snoring and obstructive sleep apnoea in adults in combination with classification, diagnosis, investigations, management, treatment and surgery. Results were limited to English language articles including case series, clinical trials, randomised controlled trials, meta‐analyses, systematic reviews and review articles. Relevant references from selected articles were also reviewed.

Results

The majority of published literature for snoring is of level II/III evidence and that for obstructive sleep apnoea being of level I/II, with 36 relevant randomised controlled trials identified. The diagnosis of obstructive sleep apnoea involves thorough clinical assessment and typically a sleep study. Snoring may be managed with lifestyle modification, intra‐oral devices or by surgical intervention, with continuous positive airway pressure being the treatment of choice for moderate‐to‐severe obstructive sleep apnoea.

Conclusions

A structured history of snoring and its associated symptoms, comprehensive examination including flexible laryngoscopy and sleep studies where relevant, in addition to targeted investigations, should lead to the correct diagnosis and appropriate management.
Comparison of steroid administration methods in patients with idiopathic sudden sensorineural hearing loss: a retrospective observational study
Authors: Kim S.H. , Jung S.Y. , Kim M.G. , Byun J.Y. , Park M.S. , Yeo S.G.
Published: October 2014

Objectives

To compare the recovery rates of patients with idiopathic sudden sensorineural hearing loss (ISSHL) treated with oral systemic steroids (PO) or intratympanic steroid injection (IT) or both.

Design

A retrospective observational study.

Setting

Tertiary referral centre.

Participants

Eight hundred and forty‐four patients diagnosed with ISSHL within 14 days of the onset of symptoms. The patients were divided into three groups by treatment modality.

Main outcome measures

Threshold of pure‐tone tests, age, accompanying symptoms and underlying diseases were compared. The level of final hearing recovery was evaluated by the application of the results of the pure‐tone test that was performed at least 3 months after the completion of each treatment.

Results

Final hearing recovery rate differed significantly by the type of treatment (P = 0.031). Recovery rates in the PO and combined groups were significantly higher in patients with mild (85.1% and 88.6%, respectively) than with profound (52.8% and 69.0%, respectively) hearing loss (P < 0.05). In contrast, severity and recovery rate were not significantly correlated in the IT group (P > 0.05). Combined treatment yielded significantly higher recovery rates than other treatment modalities in patients without hypertension (HTN) and diabetes mellitus (DM) (P = 0.021).

Conclusion

In the group treated with combined therapy, better hearing improvement was obtained than in the groups treated with systemic steroid only or with intratympanic steroid injection only without complications. These findings suggest that the combination of systemic administration and intratympanic injection may improve patient prognosis.
The Smithsonian Folklife Festival in Museological Perspective
Authors: Kurin Richard
Published: October 2014

The Smithsonian Folklife Festival began as a four‐day event held over the Fourth of July holiday in 1967, outdoors on the Mall. The impulse for it came from Smithsonian Secretary S. Dillon Ripley. The form of it came from Ralph Rinzler, field research director for the Newport Folk Festival and a documentarian who sought out authentic, grassroots American musicians. The Festival was conceived as giving voice to the less known and under‐represented, a philosophy that quickly expanded to encompass the world of what is now called intangible cultural heritage. The Festival's museology has as its core the foregrounding of the cultural exemplars and the primacy of their voices in the presentations. It has energized new possibilities for what can be done in the Smithsonian and on the National Mall, and in the lives of people, communities, and institutions well beyond.
The Smithsonian Folklife Festival and Cultural Heritage Policy in Colombia: A Case Study
Authors: Cadaval Olivia , Diaz‐Carrera Cristina
Published: October 2014

As Colombia began to develop its Intangible Cultural Heritage (ICH) policy, it signed an agreement with the Smithsonian Center for Folklife and Cultural Heritage to collaborate on a Smithsonian Folklife Festival of Colombia's national living traditions, to be shown on the National Mall in 2011. This essay addresses the role of the Smithsonian Folklife Center in advocating for a cultural heritage policy grounded in cultural democracy and intercultural dialogue, as well as its collaboration with UNESCO in crafting the 2003 convention for the protection of intangible cultural heritage. We focus on the Center's signature collaborative program, the Smithsonian Folklife Festival, and on our experience with the 2011 Festival program, Colombia: The Nature of Culture. We examine the relationship between the Festival and Colombia's intangible cultural heritage communities, policies, and practices, through intercultural dialogues that contribute to shaping Intangible Cultural Heritage policy from the bottom up.
Making Meaning on the Mall: The Smithsonian Folklife Festival as a Constructivist Museum
Authors: Belanus Betty J. , Fernandez Katie
Published: October 2014

George Hein, museum education theorist, asserts that there are five qualities a “constructivist exhibition” must have (1998, 35). The authors, assembling observations of visitor engagement and qualitative data from the 2013 Smithsonian Folklife Festival, compare the event to Hein's constructivist exhibition criteria, to assess whether the Festival allowed visitors to “make meaning,” and to see whether visitor meaning‐making meshed with the goals of the curators. The answers have the potential to help improve visitor experiences and learning outcomes at museums and other curated cultural events.
Cultivating Connectivity: Folklife and Inclusive Excellence in Museums
Authors: Dewhurst C. Kurt , N'Diaye Diana Baird , MacDowell Marsha
Published: October 2014

Today there is a growing global awareness of the need to address issues related to the safeguarding and use of both tangible and intangible heritage. By engaging with communities in the documentation of local cultures—especially their folklife, or in other words, their traditional intangible cultural heritage—museums can create collections that will serve as foundations for museum research, exhibitions, and programs that have more resonance with and relevance for those communities. Interactions of these kinds—in particular those of the Smithsonian's Center for Folklife and Cultural Heritage and the Michigan State University Museum, home of the Michigan Traditional Arts Program, as well as collaborations between the Smithsonian Folklife Festival and the Great Lakes Folk Festival, and other programs around the world—have served as important platforms for public discourse about a variety of issues and have produced programs and exhibitions both at home and around the world.
Judicialisation of Trade Policy and the Impact on National Constitutional Rights of EU Free Trade Agreements with Partner Countries in Europe
Authors: Tatham Allan F.
Published: October 2014

This article looks at the way in which the model of the European Court of Justice (ECJ) as a trade policy actor, both internally and externally, has been emulated by courts of European states with a free trade agreement with the Union. It examines in particular how, through application or rejection of—deference or defence to—EU law as interpreted by the ECJ, those courts have sought to balance the benefits of open international trade with the protection of domestic fundamental constitutional values. The article concludes by emphasising how the ‘de‐politicisation’ of trade policy through its concomitant judicialisation has allowed such courts to seise upon a role in trade policy determination, enabling them to become actors in the process of determining the rate and extent to which the Europeanisation of trade law occurs in their national systems.
Protection of Fundamental Rights in Latin American FTAs and MERCOSUR: An Exploratory Agenda
Authors: Franca‐Filho Marcilio Toscano , Lixinski Lucas , Giupponi Belén Olmos
Published: October 2014

Latin America is a fertile ground for exploring issues of trade and human rights, but relatively little seems to be written about human rights in economic integration processes across Latin America. This article is an attempt at remedying this. It is an exploratory piece that highlights some of the major issues across a wide range of Free Trade Agreements involving Latin American countries, with particular emphasis on MERCOSUR. The authors conclude that in spite of Latin America's openness to international human rights discourses, pragmatism seems to dominate trade negotiations. While human rights considerations are slowly seeping into trade negotiations, this seems to happen largely because of pressure exerted by outside actors. There appears to be a lack of true endogenous push towards human rights and trade inside the bloc.