bluuebunny/crossref_metadata_2025 huggingface dataset:
Convergence analysis of virtual element methods for semilinear parabolic problems on polygonal meshes
Authors: Adak Dibyendu , Natarajan E. , Kumar Sarvesh
Published: August 2018

In this article, we discuss and analyze new conforming virtual element methods (VEMs) for the approximation of semilinear parabolic problems on convex polygonal meshes in two spatial dimension. The spatial discretization is based on polynomial and suitable nonpolynomial functions, and a Euler backward scheme is employed for time discretization. The discrete formulation of both the proposed schemes—semidiscrete and fully discrete (with time discretization) is discussed in detail, and the unique solvability of the resulted schemes is discussed. A priori error estimates for the proposed schemes (semidiscrete and fully discrete) in H1‐ and L2‐norms are derived under the assumption that the source term f is Lipschitz continuous. Some numerical experiments are conducted to illustrate the performance of the proposed scheme and to confirm the theoretical convergence rates.
Recent advances in thermally robust, late transition metal‐catalyzed olefin polymerization
Authors: Mitchell Nolan E , Long Brian K
Published: August 2018

Olefin polymerization catalysts employing late transition metals, such as Ni, Pd, Fe and Co, have been heavily investigated since their discovery in the mid‐1990s. Despite the advantages and appeal these catalysts have displayed in academic research, their implementation in industry has remained restricted due to a variety of limitations and drawbacks. One specific limitation is the relative thermal instability of most late transition metal olefin polymerization catalysts at the temperatures commonly utilized for industrial polymerizations. This review focuses on the development of Ni‐, Pd‐, Fe‐ and Co‐based olefin polymerization catalysts that display increased thermal stability at super‐ambient reaction temperatures. These advances in thermal stability have been realized using a variety of ligand modifications, and their polymerization activities and thermal stability are summarized herein. Lastly, a brief outlook on the future of thermally stable, late transition metal olefin polymerization catalysts is provided. © 2018 Society of Chemical Industry
Triphenylamine and some of its derivatives as versatile building blocks for organic electronic applications
Authors: Blanchard Philippe , Malacrida Claudia , Cabanetos Clément , Roncali Jean , Ludwigs Sabine
Published: August 2018

This review article gives an overview of past and current activities in the Linear Conjugated Systems Group of Angers and in the IPOC – Functional Polymers Group of the Institute of Polymer Chemistry of Stuttgart on the use of triphenylamine (TPA) as versatile building block for organic electronics. In the first part, the properties of TPA itself are introduced including geometrical and energy level considerations. Dimerization of TPA to tetraphenylbenzidine upon electrochemical oxidation is highlighted. The blocking of TPA para‐positions and its implications in terms of electroactivity is further discussed. The second part shows that dimerization of TPA as pendant redox‐active moieties in polymers is a versatile strategy to crosslink polymer films. Coming from redox homopolymers the crosslinking strategy is extended towards conjugated redox polymers based on polythiophenes and block copolymers. Conductivity mechanisms and the influence of doping level on conductivity are probed with cyclic voltammetry coupled with in situ conductance and four‐point probe measurements. The last part is dedicated to the use of TPA as an electron‐donating block in the design of donor‐π‐acceptor chromophores and their use as active material in organic photovoltaics. An overview of some relevant TPA‐based push–pull molecules from the literature and our contribution to this field is presented emphasizing the progress of the photovoltaic performance of organic solar cells made over the last decade. © 2018 Society of Chemical Industry
Unique auto‐ubiquitination activities of artificial RING fingers in cancer cells
Authors: Miyamoto Kazuhide , Nakatani Arisa , Sunagawa Mayumi , Saito Kazuki
Published: August 2018

Abstract

Ubiquitin‐conjugating (E2) enzymes in protein ubiquitination are associated with various diseases. An artificial RING finger (ARF) is a useful tool, and E2 activities are conveniently estimated based on ARF reactivities. To extend the use of ARF in cells, we constructed a TAT‐ARF using a cell‐penetrating trans‐activator protein (TAT) peptide. An in vitro ubiquitination assay without substrates showed auto‐ubiquitination of TAT‐ARF via its TAT region. TAT‐ARF was translocated into MCF7 breast cancer cells, and then TAT‐ARF ubiquitinated itself via its ARF. Experiments using confocal laser‐scanning microscopy revealed that FAM‐labeled TAT‐ARF was readily internalized in cells and it remained encapsulated in vesicles. The Cell Counting Kit‐8 assay indicated that the TAT‐ARF uptake occurred without cytotoxicity in MCF7 cells at concentrations below 5.0 μM. By taking advantage of TAT‐ARF, we, for the first time, succeeded in detecting E2 activities in cells. Thus, the present work opens up new avenues in the investigation of protein ubiquitination.
The N‐terminal methyltransferase homologs NRMT1 and NRMT2 exhibit novel regulation of activity through heterotrimer formation
Authors: Faughn Jon D. , Dean William L. , Schaner Tooley Christine E.
Published: August 2018

Protein, DNA, and RNA methyltransferases have an ever‐expanding list of novel substrates and catalytic activities. Even within families and between homologs, it is becoming clear the intricacies of methyltransferase specificity and regulation are far more diverse than originally thought. In addition to specific substrates and distinct methylation levels, methyltransferase activity can be altered by complex formation with close homologs. We work with the N‐terminal methyltransferase homologs NRMT1 and NRMT2. NRMT1 is a ubiquitously expressed distributive trimethylase. NRMT2 is a monomethylase expressed at low levels in a tissue‐specific manner. They are both nuclear methyltransferases with overlapping consensus sequences but have distinct enzymatic activities and tissue expression patterns. Co‐expression with NRMT2 increases the trimethylation rate of NRMT1, and here we aim to understand how this occurs. We use analytical ultracentrifugation to show that while NRMT1 primarily exists as a dimer and NRMT2 as a monomer, when co‐expressed they form a heterotrimer. We use co‐immunoprecipitation and molecular modeling to demonstrate in vivo binding and map areas of interaction. While overexpression of NRMT2 increases the half‐life of NRMT1, the converse is not true, indicating that NRMT2 may be increasing NRMT1 activity by stabilizing the enzyme. Accordingly, the catalytic activity of NRMT2 is not needed to increase NRMT1 activity or increase its affinity for less preferred substrates. Monomethylation can also not rescue phenotypes seen with loss of trimethylation. Taken together, these data support a model where NRMT2 expression activates NRMT1 activity, not through priming, but by increasing its stability and substrate affinity.
Effect of N Concentration Upon Resistive Switching Behavior of Au/Ni/TaON/NiSi ECM Devices
Authors: Park Jingyu , Jeon Heeyoung , Jang Woochool , Kim Hyunjung , Kim Hongki , Jeon Hyeongtag
Published: August 2018

In this study, Au/Ni/TaOx/NiSi and Au/Ni/TaON/NiSi electrochemical metallization memory devices are fabricated and their resistive switching (RS) behavior is investigated. The composition of TaON is controlled by changing the N partial pressure during sputtering. The Au/Ni/TaOx/NiSi device does not function as a memory device, whereas the Au/Ni/TaON/NiSi devices show conventional ECM characteristics. In addition, the device with the highest N concentration among those fabricate exhibites the best RS characteristics, with a constant high‐resistance‐state (HRS) current level and stable retention properties over 5 × 104 s, due to the formation of strong Ni conductive filaments (CFs). The TaON film with the highest N concentration has the lowest defect density, allowing stable Ni CFs to form and thereby yielding superior device performance.
Aluminum Electrode Insulation Dynamics via Interface Oxidation by Reactant Diffusion in Organic Layers
Authors: Fluhr Daniel , Züfle Simon , Muhsin Burhan , Öttking Rolf , Seeland Marco , Roesch Roland , Schubert Ulrich S. , Ruhstaller Beat , Krischok Stefan , Hoppe Harald
Published: August 2018

Appreciable progress has been achieved in the development of organic photovoltaics (OPV) over the last decade. However, further improvement of operational stability remains a challenge. In this contribution, focus is placed on corrosion and delamination of the metal contact, which are mainly caused by oxygen or water vapor ingress but in other cases also via mechanical wear and different thermal expansion coefficients. So‐called pinholes and electrode edges provide pathways for ingress of water vapor and oxygen, which may attack the metal–organic interface. Thus, electrical insolation via formation of insulating metal oxide and concomitant mechanical delamination occurs. As charge injection and extraction is suppressed at insulated and delaminated areas, the active area contributing to power conversion gets reduced. This work links analytical and numerical predictions about the active area in contact with the electrode to experimentally observe dependencies. Spatially and time‐resolved electroluminescence measurements provide information on location, size, and growth‐rate of insulated areas. Area loss rates for dark spots depend either sub‐linear (for early stages and edge‐ingress) or linear (later stages) on time. The initial defect size has a clear impact on growth rates. Furthermore, it has possible to demonstrate titanium oxide interlayers to slow down this type of extrinsic degradation.
Temperature Dependence of Electrical Conductivity and Thermoelectric Power of Transparent SWCNT Films Obtained by Aerosol CVD Synthesis
Authors: Romanenko Anatoly I. , Bryantsev Yaroslav A. , Yakovleva Galina E. , Arkhipov Viacheslav E. , Berdinsky Alexander S. , Gusel'nikov Artem V. , Okotrub Alexander V.
Published: August 2018

The effect of pressing on temperature dependences of electrical conductivity σ(T) and thermoelectric power (Seebeck effect) S of single‐walled carbon nanotubes (SWCNTs) transparent films on polyester substrate has been studied. σ(T) has been described by the fluctuation‐induced tunneling model (FIT) conductance in the temperature range 20–298 K. At a temperature T < 20 K, three‐dimensional variable range hopping conductivity (VRHC) has been observed. Based on the estimation of current concentration n ≈1020 cm−3 from VRHC dependence, it has been found that metallic SWCNTs have made the main contribution to conductivity at T < 20 K. The value n obtained from S has been similar to the value obtained from VRHC estimation. The energy barrier between SWCNTs has been changed by pressing of films. Such pressing has led to increase in the electrical conductivity of the film by two orders of magnitude at room temperature. The measurement of conductivity in the process of synthesis has allowed us to control the repeatability of results and select samples with the necessary resistance values. Raman and optical spectroscopy, SEM and TEM have been used to determine the structural and geometric characteristics of the SWCNTs.
Bulk matter and the boundary quantum null energy condition
Authors: Khandker Zuhair U. , Kundu Sandipan , Li Daliang
Published: August 2018

Abstract

We investigate the quantum null energy condition (QNEC) in holographic CFTs, focusing on half-spaces and particular classes of states. We present direct, and in certain cases nonperturbative, calculations for both the diagonal and off-diagonal variational derivatives of entanglement entropy. In d ≥ 3, we find that the QNEC is saturated. We compute relations between the off-diagonal variation of entanglement, boundary relative entropy, and the bulk stress tensor. Strong subadditivity then leads to energy conditions in the bulk. In d = 2, we find that the QNEC is in general not saturated when the Ryu-Takayanagi surface intersects bulk matter. Moreover, when bulk matter is present the QNEC can imply new bulk energy conditions. For a simple class of states, we derive an example that is stronger than the bulk averaged null energy condition and reduces to it in certain limits.
Holographic entanglement entropy in AdS4/BCFT3 and the Willmore functional
Authors: Seminara Domenico , Sisti Jacopo , Tonni Erik
Published: August 2018

Abstract

We study the holographic entanglement entropy of spatial regions having arbitrary shapes in the AdS4/BCFT3 correspondence with static gravitational backgrounds, focusing on the subleading term with respect to the area law term in its expansion as the UV cutoff vanishes. An analytic expression depending on the unit vector normal to the minimal area surface anchored to the entangling curve is obtained. When the bulk spacetime is a part of AdS4, this formula becomes the Willmore functional with a proper boundary term evaluated on the minimal surface viewed as a submanifold of a three dimensional flat Euclidean space with boundary. For some smooth domains, the analytic expressions of the finite term are reproduced, including the case of a disk disjoint from a boundary which is either flat or circular. When the spatial region contains corners adjacent to the boundary, the subleading term is a logarithmic divergence whose coefficient is determined by a corner function that is known analytically, and this result is also recovered. A numerical approach is employed to construct extremal surfaces anchored to entangling curves with arbitrary shapes. This analysis is used both to check some analytic results and to find numerically the finite term of the holographic entanglement entropy for some ellipses at finite distance from a flat boundary.
The analytic bootstrap for large N Chern-Simons vector models
Authors: Aharony Ofer , Alday Luis F. , Bissi Agnese , Yacoby Ran
Published: August 2018

Abstract

Three-dimensional Chern-Simons vector models display an approximate higher spin symmetry in the large N limit. Their single-trace operators consist of a tower of weakly broken currents, as well as a scalar σ of approximate twist 1 or 2. We study the consequences of crossing symmetry for the four-point correlator of σ in a 1/N expansion, using analytic bootstrap techniques. To order 1/N we show that crossing symmetry fixes the contribution from the tower of currents, providing an alternative derivation of well-known results by Maldacena and Zhiboedov. When σ has twist 1 its OPE receives a contribution from the exchange of σ itself with an arbitrary coefficient, due to the existence of a marginal sextic coupling. We develop the machinery to determine the corrections to the OPE data of double-trace operators due to this, and to similar exchanges. This in turns allows us to fix completely the correlator up to three known truncated solutions to crossing. We then proceed to study the problem to order 1/N
2. We find that crossing implies the appearance of odd-twist double-trace operators, and calculate their OPE coefficients in a large spin expansion. Also, surprisingly, crossing at order 1/N
2, implies non-trivial O(1/N) anomalous dimensions for even-twist double-trace operators, even though such contributions do not appear in the four-point function at order 1/N (in the case where there is no scalar exchange). We argue that this phenomenon arises due to operator mixing. Finally, we analyse the bosonic vector model with a sextic coupling without gauge interactions, and determine the order 1/N
2 corrections to the dimensions of twist-2 double-trace operators.
Yukawa couplings from magnetized D-brane models on non-factorisable tori
Authors: Förste Stefan , Liyanage Christoph
Published: August 2018

Abstract

We compute Yukawa couplings in type IIB string theory compactified on a non factorisable six-torus in the presence of D9 branes and fluxes. The setting studied in detail, is obtained by T-dualising an intersecting brane configuration of type IIA theory compactified on a torus generated by the SO(12) root lattice. Particular deformations of such torus are taken into account and provide moduli dependent couplings. Agreement with the type IIA result is found in a non trivial way. The classical type IIB calculation gives also information on a factor accessible only by quantum computations on the type IIA side.
Pastoral Leadership and Congregational Vitality
Authors: Wollschleger Jason
Published: August 2018

This research note presents unexpected findings on the role of pastoral leadership styles on congregational vitality. Drawn from a most-similar case study of two mainline congregations, one that has experience growth and vitality the other significant decline, the results indicate that leadership style is an under-studied contributing factor in congregational vitality. The findings demonstrate that pastoral style that is collaborative but decisive, as well as inspiring has a positive impact on congregational vitality; whereas a pastoral style that is more hands-off, seeking to empower lay decision making has a negative impact.
Heat shields boost battery safety in electric vehicles
Authors: Atkinson Simon
Published: August 2018

Freudenberg Sealing Technologies has developed an innovative heat shield for use in prismatic and pouch cells, with almost no impact on the required installation space. Designed for use in batteries that power electric vehicles, it combines the high heat resistance of a silicone-based elastomer with the insulating properties of air.
Cosmological Arguments
Authors: Almeida Michael
Published: August 2018

The book discusses the structure, content, and evaluation of cosmological arguments. The introductory chapter investigates features essential to cosmological arguments. Traditionally, cosmological arguments are distinguished by their appeal to change, causation, contingency or objective becoming in the world. But none of these is in fact essential to the formulation of cosmological arguments. Chapters 1-3 present a critical discussion of traditional Thomistic, Kalam, and Leibnizian cosmological arguments, noting various advantages and disadvantages of these approaches. Chapter 4 offers an entirely new approach to the cosmological argument - the approach of theistic modal realism. The proper explananda of cosmological arguments on this approach is not change, causation, contingency or objective becoming in the world. The proper explananda is the totality of metaphysical reality - all actualia and all possibilia. The result is the most compelling and least objectionable version of the cosmological argument.
A Nation of Investors or a Procession of Fools? Reevaluating the Behavior of Britain’s Shareholding Population through the Prism of the Interwar Sharepushing Crime Wave
Authors: HOLLOW MATTHEW
Published: August 2018

In recent years, there has been a notable increase in the amount of scholarship on the history of shareholding in Britain. One area that still remains relatively unexplored, however, is the problematic issue of how British investors actually went about the process of choosing their respective investments. The purpose of this article is to make a start at redressing this gap by using the (perceived) sharepushing crime wave that swept across Britain during the interwar period as a prism through which to evaluate the behavior of Britain’s shareholding population at this time. Ultimately, what it suggests is that, while the interwar British investors may well have had far more potential sources of advice and information open to them than their nineteenth-century forebears, this did not necessarily mean that they were any better informed about the workings of the British securities market.
Heat Transfer Analysis of a Williamson Micropolar Nanofluid with Different Flow Controls
Authors: Muthtamilselvan M. , Ramya E. , Doh D. H. , Cho G. R.
Published: August 2018

The present model is devoted for the steady stagnation point flow of a Williamson micropolar nanofluid with magneto-hydrodynamics and thermal radiation effects passed over a horizontal porous stretching sheet. The fluid is considered to be gray, absorbing-emitting but non-scattering medium. The Cogley-Vincent-Gilles formulation is adopted to simulate the radiation component of heat transfer. By applying similarity analysis, the governing partial differential equations are transformed into a set of non-linear ordinary differential equations and they are solved by using the bvp4c package in MATLAB. Numerical computations are carried out for various values of the physical parameters. The effects of momentum, microrotation, temperature and nanoparticle volume fraction profiles together with the reduced skin friction coefficient, reduced Nusselt number and reduced Sherwood number of both active and passive controls on the wall mass flux are graphically presented. The present results are compared with previously obtained solutions and they are in good agreement. Results show that the skin friction is increasing functions of the Williamson parameter in both stretching and shrinking surfaces.
Supplementing Q-method with narratives: Contextualizing CEOs’ values for family firms
Authors: Pötschke Ivonne
Published: August 2018

Values in family firms are influenced by the complex interplay of family and business. Thus, research requires methods that grasp this complexity. This paper presents a fresh methodological approach for family business research with the example of an in-depth analysis of CEOs’ value orientations. Benefits of an integrated use of two qualitative methods – Q-sorts and narrative interviews – which were collected and analyzed for 16 CEOs of family firms are illustrated. Q-method was used to build value patterns, whereas narrative interviews were conducted to reveal how values were contextualized and interpreted. This integrated approach builds qualitative richness in different ways: first, by allowing for a deep understanding of individual experience; second, by providing more contextual insight, and third, by capturing the meaning of abstract values. The approach advanced here can be reproduced for other complex organizational dynamics. Thus, this user-friendly approach is particularly suited for organizational research in a managerial environment.
Human resource management as key pillar of company strategy: Analysis of the line managers’ perception
Authors: Navío-Marco Julio , Solórzano-García Marta , Palencia-González Francisco J.
Published: August 2018

The increasingly frequent involvement of companies’ line managers in human resource (HR) activities leads us to investigate the strategic value that these managers grant HR. This research focusses on the line managers’ perception of the strategic importance of HR, versus the perception of HR managers themselves, as a relevant factor in line managers’ own involvement within the execution of HR-related tasks. If line managers do not perceive the relevance and strategic importance of HR and its key role in the company’s strategy and performance, it is difficult to guarantee the managers’ commitment and effectiveness in HR management implementation. Based on interviews with HR development and line managers in 100 Spanish firms, we verified discrepancies in HR versus line managers’ perceptions, confirming that the assessment given by the line managers is slightly lower and, in turn, providing us with references to draw useful conclusions for a successful implementation of HR practices.
How do Educators of Students With Disabilities in Specialist Settings Understand and Apply the Australian Curriculum Framework?
Authors: Walker Peter M. , Carson Karyn L. , Jarvis Jane M. , McMillan Julie M. , Noble Anna G. , Armstrong David J. , Bissaker Kerry A. , Palmer Carolyn D.
Published: August 2018

Despite aspirations to be a world-class national curriculum, the Australian Curriculum (AC) has been criticised as ‘manifestly deficient’ (Australian Government Department of Education and Training, 2014 p. 5) as an inclusive curriculum, failing to meet the needs of all students with disabilities (SWD) and their teachers. There is a need for research into the daily attempts of educators to navigate the tension between a ‘top-down’ system-wide curriculum and a ‘bottom-up’ regard for individual student needs, with a view to informing both policy and practice. This article is the first of two research papers in which we report the findings from a national online Research in Special Education (RISE) Australian Curriculum Survey of special educators in special schools, classes, and units regarding their experience using the AC to plan for and teach SWD. Survey results indicated (a) inconsistent use of the AC as the primary basis for developing learning objectives and designing learning experiences, (b) infrequent use of the achievement standards to support assessment and reporting, and (c) considerable supplementation of the AC from other resources when educating SWD. Overall, participants expressed a lack of confidence in translating the AC framework into a meaningful curriculum for SWD. Implications for policy, practice, and future research are discussed.
Late Pleistocene and Holocene ice-wedge activity on the Blackstone Plateau, central Yukon, Canada
Authors: Grinter Mike , Lacelle Denis , Baranova Natalia , Murseli Sarah , Clark Ian D.
Published: August 2018

Ice-wedge activity can be used to reconstruct past environmental conditions. We investigated the moisture source and timing of ice-wedge formation on the Blackstone Plateau. A section of permafrost exposed ice wedges that developed at two distinct depths: the first set formed syngenetically and penetrated alluvial silts from the top of permafrost; the second set, truncated by an erosional or thaw contact, was found solely in icy muddy gravels (>3.1 m depth). The δ18O and D-excess records of the ice wedges suggest that they formed from freezing of snow meltwater whose isotopic composition evolved during meltout. The14CDOCresults suggest that climate was favorable to ice-wedge growth between 32,000–30,000 and 14,000–12,500 cal yr BP, but there was likely a hiatus during the last glacial maximum due to climate being too dry. During the early to mid-Holocene, ice wedges were inactive as a result of warmer and wetter climate. Ice wedge re-initiated around 6360 cal yr BP, with a peak in activity between 3980 and 920 cal yr BP, a period characterized by cool and moist climate. Overall, timing of ice-wedge activity was broadly consistent with the climate and vegetation evolution in the western Arctic.
SYSTOLIC FILLINGS OF SURFACES
Authors: SANKI BIDYUT
Published: August 2018

A filling of a closed hyperbolic surface is a set of simple
closed geodesics whose complement is a disjoint union of hyperbolic
polygons. The systolic length is the length of a shortest
essential closed geodesic on the surface. A geodesic is called systolic, if
the systolic length is realised by its length. For every $g\geq 2$, we construct closed hyperbolic surfaces of genus $g$ whose systolic geodesics fill the surfaces with
complements consisting of only two components. Finally, we remark that one
can deform the surfaces obtained to increase the systole.
Rothschild reversed: explaining the exceptionalism of biomedical research, 1971–1981
Authors: DAVIES STEPHEN M.
Published: August 2018

The ‘Rothschild reforms’ of the early 1970s established a new framework for the management of government-funded science. The subsequent dismantling of the Rothschild system for biomedical research and the return of funds to the Medical Research Council (MRC) in 1981 were a notable departure from this framework and ran contrary to the direction of national science policy. The exceptionalism of these measures was justified at the time with reference to the ‘particular circumstances’ of biomedical research. Conventional explanations for the reversal in biomedical research include the alleged greater competence and higher authority of the MRC, together with its claimed practical difficulties. Although they contain some elements of truth, such explanations are not wholly convincing. Alternative explanations hinge on the behaviour of senior medical administrators, who closed ranks to ensure that de facto control was yielded to the MRC. This created an accountability deficit, which the two organizations jointly resolved by dismantling the system for commissioning biomedical research. The nature and working of medical elites were central to this outcome.
Variation of the Variety of Minimal Rational Tangents of Cyclic Coverings
Authors: Kim Hosung
Published: August 2018

Let π:X→ ℙnbe thed-cyclic covering branched along a smooth hypersurfaceY⊂ ℙnof degreed, 3 ≤d≤n. We identify the minimal rational curves onXwithd-tangent lines ofYand describe the scheme structure of the variety of minimal rational tangents 𝒞x⊂ ℙTx(X) at a general pointx∈X. We also show that the projective isomorphism type of 𝒞xvaries in a maximal way asxmoves over general points ofX.
Accounting Losses as a Heuristic for Managerial Failure: Evidence from CEO Turnovers
Authors: Ghosh Aloke (Al) , Wang Jun
Published: August 2018

We study the effects of accounting losses on chief executive officer (CEO) turnover. If accounting losses provide incremental information about managerial ability, boards can utilize the information in losses to assess CEOs’ stewardship of assets, which is why losses may serve as a heuristic for managerial failure. We find a positive relation between losses and subsequent CEO turnover after controlling for other accounting and stock-performance measures. We also find that losses are associated with an increase in board activity and that losses predict poor operating performance and future financial problems. Our results explain why CEOs manage earnings to avoid losses.
Saccular otoconia as a cause of Ménière's disease: hypothesis based on two theories
Authors: Hornibrook J
Published: August 2018

Background

The cause of Ménière's disease remains enigmatic after 156 years. Schuknecht's rupture and potassium intoxication theory of attacks was based on histological studies.

Objectives

This paper aimed to: present the most contemporary evidence indicating that ruptures do not usually occur, and discuss the possibility that detached saccular otoconia are the main cause of Ménière's disease; and to establish an unequivocal definition of the age of Ménière's disease onset.

Method

The paper reviews the electrophysiological basis of the Gibson–Arenberg drainage theory used to explain vertigo attacks. The current, limited knowledge of the likely fate of detached saccular otoconia is discussed.

Results

Electrophysiological studies during attacks do not support endolymph ruptures, but rather endolymph flowing in one direction and then in the opposite direction. Age of onset for Ménière's disease parallels that for benign paroxysmal positional vertigo.

Conclusion

The similarity of age of onset spectrum for Ménière's disease and benign paroxysmal positional vertigo raises the possibility that the two conditions have the same fundamental cause.
Diagnosis and treatment of necrotising otitis externa and diabetic foot osteomyelitis – similarities and differences
Authors: Peled C , Kraus M , Kaplan D
Published: August 2018

Objective

Necrotising otitis externa is a severe inflammatory process affecting soft tissue and bone, mostly in diabetic patients. Diabetic patients are also at risk of diabetic foot osteomyelitis, another inflammatory condition involving soft tissue and bone. This review aimed to describe the similarities and differences of these entities in an attempt to further advance the management of necrotising otitis externa.

Method

A PubMed search was conducted using the key words ‘otitis externa’, ‘necrotising otitis externa’, ‘malignant otitis externa’, ‘osteomyelitis’ and ‘diabetic foot’.

Results and conclusion

The similarities regarding patient population and pathophysiology between necrotising otitis externa and diabetic foot osteomyelitis raise basic questions concerning the effects of long-standing diabetes on the external ear. The concordance between local swabs and bone cultures in diabetic foot osteomyelitis is less than 50 per cent. If this holds true also to necrotising otitis externa, the role of deep tissue cultures should be strongly considered. Similar to diabetic foot osteomyelitis, magnetic resonance imaging should be considered in selected necrotising otitis externa subgroups.
Dislocation of cochlear implant magnet during 1.5 Tesla magnetic resonance imaging despite head bandaging, and its repositioning using an endoscopic approach
Authors: Leong W J C , Yuen H W
Published: August 2018

Background

Dislocation of the cochlear implant magnet is an uncommon but recognised complication of magnetic resonance imaging in a patient with a cochlear implant.

Case report

This paper reports a case of cochlear implant magnet dislocation despite head bandaging. The patient subsequently underwent endoscopic repositioning of the magnet under general anaesthesia. The cochlear implant system was tested intra-operatively and confirmed to be functioning. The patient was well at follow up and the small wound healed well with no complications.

Conclusion

This report presents the endoscopic technique as a viable minimally invasive surgical approach to address cochlear implant magnet dislocation.
Defining a combined constellation of complicated bereavement and PTSD and the psychosocial correlates associated with the pattern amongst refugees from West Papua
Authors: Tay Alvin Kuowei , Rees Susan , Tam Natalino , Kareth Moses , Silove Derrick
Published: August 2018

Background

Refugees are at risk of experiencing a combined constellation of complicated bereavement and posttraumatic stress disorder (PTSD) symptoms following exposure to complex traumas associated with personal threat and loss. Features of identity confusion are central to both complicated bereavement and PTSD and these characteristics may be particularly prominent amongst refugees from traditional cultures displaced from their homelands, families, and kinship groups. We investigate whether a combined pattern of complicated bereavement and PTSD can be identified amongst West Papuan refugees participating in an epidemiological survey (n = 486, response rate: 85.8%) in a remote town in Papua New Guinea.

Methods

Latent class analysis was applied to derive subpopulations of refugees based on symptoms of complicated bereavement and PTSD. Associations were examined between classes and traumatic loss events, post-migration living difficulties (PMLDs), and psychosocial support systems.

Results

The four classes identified comprised a complicated bereavement class (11%), a combined posttraumatic bereavement class (10%), a PTSD class (11%), and a low symptom class (67%). Symptoms of identity confusion were prominent in the posttraumatic bereavement class. Compared with the low symptom class, the combined posttraumatic bereavement class reported greater exposure to traumatic loss events (OR 2.43, 95% CI 1.11–5.34), PMLDs (OR 2.24, 95% CI 1.01–4.6), disruptions to interpersonal bonds and networks (OR 3.3, 95% CI 1.47–7.38), and erosion of roles and identities (OR 2.18, 95% CI 1.11–4.27).

Conclusions

Refugees appear to manifest a combined pattern of complicated bereavement and PTSD symptoms in which identity confusion is a prominent feature. This response appears to reflect the combined impact of high levels of exposure to traumatic losses, PMLDs, and disruption of relevant psychosocial systems.
Dynamic changes in white matter microstructure in anorexia nervosa: findings from a longitudinal study
Authors: von Schwanenflug Nina , Müller Dirk K. , King Joseph A. , Ritschel Franziska , Bernardoni Fabio , Mohammadi Siawoosh , Geisler Daniel , Roessner Veit , Biemann Ronald , Marxen Michael , Ehrlich Stefan
Published: August 2018

Background

Gray matter (GM) ‘pseudoatrophy’ is well-documented in patients with anorexia nervosa (AN), but changes in white matter (WM) are less well understood. Here we investigated the dynamics of microstructural WM brain changes in AN patients during short-term weight restoration in a combined longitudinal and cross-sectional study design.

Methods

Diffusion-weighted images were acquired in young AN patients before (acAN-Tp1, n = 56) and after (acAN-Tp2, n = 44) short-term weight restoration as well as in age-matched healthy controls (HC, n = 60). Images were processed using Tract-Based-Spatial-Statistics to compare fractional anisotropy (FA) across groups and timepoints.

Results

In the cross-sectional comparison, FA was significantly reduced in the callosal body in acAN-Tp1 compared with HC, while no differences were found between acAN-Tp2 and HC. In the longitudinal arm, FA increased with weight gain in acAN-Tp2 relative to acAN-Tp1 in large parts of the callosal body and the fornix, while it decreased in the right corticospinal tract.

Conclusions

Our findings reveal that dynamic, bidirectional changes in WM microstructure in young underweight patients with AN can be reversed with brief weight restoration therapy. These results parallel those previously observed in GM and suggest that alterations in WM in non-chronic AN are also state-dependent and rapidly reversible with successful intervention.
Efficacy of exposure-based cognitive behaviour therapy for post-traumatic stress disorder in emergency service personnel: a randomised clinical trial
Authors: Bryant Richard A. , Kenny Lucy , Rawson Natasha , Cahill Catherine , Joscelyne Amy , Garber Benjamin , Tockar Julia , Dawson Katie , Nickerson Angela
Published: August 2018

Background

Although emergency service personnel experience markedly elevated the rates of post-traumatic stress disorder (PTSD), there are no rigorously conducted trials for PTSD in this population. This study assessed the efficacy of cognitive behaviour therapy (CBT) for PTSD in emergency service personnel, and examined if brief exposure (CBT-B) to trauma memories is no less efficacious as prolonged exposure (CBT-L).

Method

One hundred emergency service personnel with PTSD were randomised to either immediate CBT-L, CBT-B or wait-list (WL). Following post-treatment assessment, WL participants were randomised to an active treatment. Participants randomised to CBT-L or CBT-B were assessed at baseline, post-treatment and at 6-month follow-up. Both CBT conditions involved 12 weekly individual sessions comprising education, CBT skills building, imaginal exposure, in vivo exposure, cognitive restructuring and relapse prevention. Imaginal exposure occurred for 40 min per session in CBT-L and for 10 min in CBT-B.

Results

At post-treatment, participants in WL had smaller reductions in PTSD severity (Clinician Administered PTSD Scale), depression, maladaptive appraisals about oneself and the world, and smaller improvements on psychological and social quality of life than CBT-L and CBT-B. There were no differences between CBT-L and CBT-B at follow-up on primary or secondary outcome measures but both CBT-L and CBT-B had large baseline to follow-up effect sizes for reduction of PTSD symptoms.

Conclusions

This study highlights that CBT, which can include either long or brief imaginal exposure, is efficacious in reducing PTSD in emergency service personnel.
Understanding the structure, experiences and challenges of social support for older lesbian, gay and bisexual people: a systematic review
Authors: Hawthorne Oliver , Camic Paul M. , Rimes Katharine A.
Published: August 2018

The psycho-social contexts of older lesbian, gay and bisexual (LGB) individuals suggest that they may face unique strengths and barriers in accessing social support. The present review aimed to explore what is known about this by providing a synthesis of this area of research and a methodological critique. The Applied Social Sciences Index (ASSIA), Psychinfo and Medline databases were searched and 22 relevant articles were identified. Key findings were extracted and quality was assessed using a standardised rating scale. The findings indicated that although many older LGB people report similar-sized support networks to older heterosexuals, more support came from friends and less from biological family members. Many reported not receiving enough support; it is possible that differences in care-giving between friends and family and anticipated social support difficulties due to previous LGB-stigma experiences partially account for this. Current recruitment strategies may mean that more-connected older LGB people are over-represented in research. There is a lack of research with the ‘old-old’ population, bisexual people, those with significant health needs, those outside the United States of America and those with additional characteristics associated with discrimination. Practical and research implications are discussed and it is suggested that friendship–carer dyads may need support to have more explicit discussions about care-giving roles due to a lack of societal templates for these kinds of relationships.
The contribution of dementia to the disparity in family wealth between black and non-black Americans
Authors: Kaufman Jennifer E. , Gallo William T. , Fahs Marianne C.
Published: August 2018

The enormous economic burden of dementia in the United States of America falls disproportionately on families coping with this devastating disease. Black Americans, who are at greater risk of developing dementia than white Americans, hold on average less than one-eighth of the wealth of white Americans. This study explores whether dementia exacerbates this wealth disparity by examining dementia's effect on wealth trajectories of black versus non-black Americans over an eight-year period preceding death, using five waves of data (beginning in 2002 or 2004) on decedents in the 2012 and 2014 waves of the Health and Retirement Study (N = 2,429). Dementia is associated with a loss of 97 per cent of wealth among black Americans, compared with 42 per cent among non-black Americans, while wealth loss among black and non-black Americans without dementia did not differ substantially (15% versus 19%). Dementia appears to increase the probability of wealth exhaustion among both black and non-black Americans, although the estimate is no longer significant after adjusting for all covariates (for blacks, odds ratio (OR) = 2.04, 95% confidence interval (CI) = 0.83, 5.00; for non-blacks, OR = 1.47, 95% CI = 0.95, 2.27). Dementia has a negative association with home-ownership, and the loss or sale of a home may play a mediating role in the exhaustion of wealth among black Americans with dementia.
Perceptions of older people in Ireland and Australia about the use of technology to address falls prevention
Authors: Mackenzie Lynette , Clifford Amanda
Published: August 2018

Falls are common events with serious consequences for older people. With an ageing population and increasing health-care costs, information and communication technologies (ICT) will have a potential role in future health-care delivery. However, research on technology acceptance in health care for older people is limited and its application to falls prevention is unknown. The aims of this study were to explore and describe the perceptions of community-dwelling Australian and Irish older people about their current use of technology, and the potential use of technology for falls prevention. Qualitative data were collected from three focus groups conducted in and around Limerick in Ireland, and three in the Sydney area, Australia. A total of 35 older people participated. Data were analysed using thematic analysis. Four themes emerged from the data: (a) perceptions of vulnerability to falls, (b) preferences for exercise interventions, (c) participation in and ownership of technology, and (d) perceptions about applications of technology for falls prevention. As the use of technology is an instrumental activity of daily living, health professionals need to assess the capacity of older people to adopt these technologies, and provide falls prevention interventions to accommodate the technology skills of older people. Some participants were reluctant to embrace technology and barriers to the effective use of technology to assist in preventing falls may conflict with future health service trends.
Corporate Democracy: How Corporations Justified Their Right to Speak in 1970s Boston
Authors: Bowie Nikolas
Published: August 2018

In the early 1970s, the executives of the First National Bank of Boston spent hundreds of thousands of the bank's dollars on ads opposing statewide efforts to raise their personal income taxes. When frustrated Massachusetts legislators banned this sort of corporate spending, the executives sued, arguing that “corporations have the same First Amendment rights as individuals.” In First National Bank of Boston v. Bellotti, the Supreme Court held for the first time that the First Amendment protects all political speech, even ads paid for by a corporation. Surprisingly, the first corporation to take advantage of this decision was not the bank, but the city of Boston--a municipal corporation that spent nearly a million dollars on a new referendum in the fall of 1978.

This article discusses the history of the 1978 referendum, one pitting municipal corporations against business corporations. It argues that the referendum and the discourse surrounding it made it intuitive for Bostonians that all corporations, banks and cities, are representative institutions. Corporations can “speak” only by spending money, and the leaders of Boston and the bank justified spending other people's money by pointing to the internal elections that put them in office. But voters were skeptical of the argument that “corporate democracy” alone could guarantee that elected executives spoke with the consent of the people they purported to represent. The article offers a novel contribution to the historiography of modern business and politics: a legal history of how corporations--municipal and financial--became politicized in the wake of evolving First Amendment free-speech doctrine.
Maternal infection during pregnancy and type 1 diabetes mellitus in offspring: a systematic review and meta-analysis
Authors: Yue Y. , Tang Y. , Tang J. , Shi J. , Zhu T. , Huang J. , Qiu X. , Zeng Y. , Li W. , Qu Y. , Mu D.
Published: August 2018

Previous studies have demonstrated that type 1 diabetes mellitus (T1DM) could be triggered by an early childhood infection. Whether maternal infection during pregnancy is associated with T1DM in offspring is unknown. Therefore, we aimed to study the association using a systematic review and meta-analysis. Eighteen studies including 4304 cases and 25 846 participants were enrolled in this meta-analysis. Odds ratios (ORs) and 95% confidence intervals (CIs) were synthesised using random-effects models. Subgroup analyses and sensitivity analyses were conducted to assess the robustness of associations. Overall, the pooled analysis yielded a statistically significant association between maternal infection during pregnancy and childhood T1DM (OR 1.31, 95% CI 1.07–1.62). Furthermore, six studies that tested maternal enterovirus infection showed a pooled OR of 1.54 (95% CI 1.05–2.27). Heterogeneity from different studies was evident (I2= 70.1%,P< 0.001) and was mainly attributable to the different study designs, ascertaining methods and sample size among different studies. This study provides evidence for an association between maternal infection during pregnancy and childhood T1DM.