bluuebunny/crossref_metadata_2025_split huggingface dataset:
Informing Ex Ante Event Studies with Macro‐Econometric Evidence on the Structural and Policy Impacts of Terrorism
Authors: Nassios Jason , Giesecke James A. 
Published: August 2017

AbstractEconomic consequence analysis is one of many inputs to terrorism contingency planning. Computable general equilibrium (CGE) models are being used more frequently in these analyses, in part because of their capacity to accommodate high levels of event‐specific detail. In modeling the potential economic effects of a hypothetical terrorist event, two broad sets of shocks are required: (1) physical impacts on observable variables (e.g., asset damage); (2) behavioral impacts on unobservable variables (e.g., investor uncertainty). Assembling shocks describing the physical impacts of a terrorist incident is relatively straightforward, since estimates are either readily available or plausibly inferred. However, assembling shocks describing behavioral impacts is more difficult. Values for behavioral variables (e.g., required rates of return) are typically inferred or estimated by indirect means. Generally, this has been achieved via reference to extraneous literature or ex ante surveys. This article explores a new method. We elucidate the magnitude of CGE‐relevant structural shifts implicit in econometric evidence on terrorist incidents, with a view to informing future ex ante event assessments. Ex post econometric studies of terrorism by Blomberg et al. yield macro econometric equations that describe the response of observable economic variables (e.g., GDP growth) to terrorist incidents. We use these equations to determine estimates for relevant (unobservable) structural and policy variables impacted by terrorist incidents, using a CGE model of the United States. This allows us to: (i) compare values for these shifts with input assumptions in earlier ex ante CGE studies; and (ii) discuss how future ex ante studies can be informed by our analysis.
The Influence of Cytomegalovirus on Expression of HLA‐G and its Ligand KIR2DL4 by Human Peripheral Blood Leucocyte Subsets
Authors: Albayati Z. , Alyami A. , Alomar S. , Middleton D. , Bonnett L. , Aleem S. , Flanagan B. F. , Christmas S. E. 
Published: August 2017

AbstractHLA‐G is a non‐classical class I HLA antigen, normally expressed in high levels only on extravillous cytotrophoblast. It has immunosuppressive properties in pregnancy and has also been found to be upregulated on leucocytes in viral infection. In this study, proportions of all leucocyte subsets expressing HLA‐G were found to be low in healthy subjects positive or negative for cytomegalovirus (CMV). Significantly greater proportions of CD4+ CD69+ and CD56+ T cells expressed HLA‐G compared to other T cells. However, following stimulation with CMV antigens or intact CMV, proportions of CD4+, CD8+, CD69+ and CD56+ T cells, and also B cells expressing HLA‐G, were significantly increased in CMV+ subjects. Despite some subjects having alleles of HLA‐G associated with high levels of expression, no relationship was found between HLA‐G genotype and expression levels. Purified B cells from CMV+ subjects stimulated in mixed culture with CMV antigens showed significantly increased HLA‐G mRNA expression by real‐time polymerase chain reaction. Serum levels of soluble HLA‐G were similar in CMV− and CMV+ subjects but levels in culture supernatants were significantly higher in cells from CMV+ than from CMV− subjects stimulated with CMV antigens. The HLA‐G ligand KIR2DL4 was mainly expressed on NK cells and CD56+ T cells with no differences between CMV+ and CMV− subjects. Following stimulation with IL‐2, an increase in the proportion of CD56+ T cells positive for KIR2DL4 was found, together with a significant decrease in CD56dimCD16+ NK cells. The results show that CMV influences HLA‐G expression in healthy subjects and may contribute to viral immune evasion.
Partially Linear Additive Models with Unknown Link Functions
Authors: Zhang Jun , Lian Heng 
Published: August 2017

AbstractIn this paper, we consider partially linear additive models with an unknown link function, which include single‐index models and additive models as special cases. We use polynomial spline method for estimating the unknown link function as well as the component functions in the additive part. We establish that convergence rates for all nonparametric functions are the same as in one‐dimensional nonparametric regression. For a faster rate of the parametric part, we need to define appropriate ‘projection’ that is more complicated than that defined previously for partially linear additive models. Compared to previous approaches, a distinct advantage of our estimation approach in implementation is that estimation directly reduces estimation in the single‐index model and can thus deal with much larger dimensional problems than previous approaches for additive models with unknown link functions. Simulations and a real dataset are used to illustrate the proposed model.
Social media and the doping of sport surveillance
Authors: Sefiha Ophir , Reichman Nancy 
Published: August 2017

AbstractReviewing literatures from sociology of sport, surveillance, and internet studies, we consider the processes by which social media regulate the behavior of athletes. Nowhere is this more evident than in the current regulation of anti‐doping in elite sport where athletes' social media postings have been highly critical of fellow competitors. As social media becomes increasingly blended into everyday routines, this form of surveillance extends the gaze of those who watch and increases the pressure for online disclosure while making traditional distinctions between formal and informal social control less meaningful. Contemporary social media acts as a form of social control that has become more preemptive and grassroots. When athletes internalize surveillance and disclosure as consistent with their professional norms, the power relationships that surround sport performance become increasingly difficult to discern. This article helps to illuminate the ways in which surveillance through social media have become a part of everyday routines, extends and amplifies the power of more traditional agents of surveillance, and calls for continued research into the role of contemporary social media as a surveillance practice.
‘Replacement Care’ for Working Carers? A Longitudinal Study in England, 2013–15
Authors: Pickard Linda , Brimblecombe Nicola , King Derek , Knapp Martin 
Published: August 2017

AbstractIn the context of rising need for long‐term care, reconciling unpaid care and carers’ employment is becoming an important social issue. In England, there is increasing policy emphasis on paid services for the person cared for, sometimes known as ‘replacement care’, to support working carers. Previous research has found an association between ‘replacement care’ and carers’ employment. However, more information is needed on potential causal connections between services and carers’ employment. This mixed methods study draws on new longitudinal data to examine service receipt and carers’ employment in England. Data were collected from carers who were employed in the public sector, using self‐completion questionnaires in 2013 and 2015, and qualitative interviews were conducted with a sub‐sample of respondents to the 2015 questionnaire. We find that, where the person cared for did not receive at least one ‘key service’ (home care, personal assistant, day care, meals, short‐term breaks), the carer was subsequently more likely to leave employment because of caring, suggesting that the absence of services contributed to the carer leaving work. In the interviews, carers identified specific ways in which services helped them to remain in employment. We conclude that, if a policy objective is to reduce the number of carers leaving employment because of caring, there needs to be greater access to publicly‐funded services for disabled and older people who are looked after by unpaid carers.
Short‐term residual N unaffected by forbs in grass‐clover mixtures
Authors: Dhamala N. R. , Rasmussen J. , Cong W.‐F. , Carlsson G. , Søegaard K. , Eriksen J. 
Published: August 2017

AbstractWe determined the effect on residual nitrogen (N) of including forbs (chicory, ribwort plantain and caraway) in perennial ryegrass‐red clover mixtures. Although soil N inputs during the grassland phase differed markedly between mixtures, in a pot experiment we found no differences in the potentially mineralizable N of the soil or in the dry matter production and N content of the spring barley test crop. The fertilizer value of the grassland mixtures corresponded to 10 g N/m2, irrespective of forb inclusion. Thus, the inclusion of nonlegume forbs did not negatively affect short‐term residual N fertility of legume‐based grasslands.
Detection of Cyprinid Herpesvirus 1 DNA in cutaneous squamous cell carcinoma of koi carp (Cyprinus carpio)
Authors: Sirri Rubina , Ciulli Sara , Barbé Tim , Volpe Enrico , Lazzari Maurizio , Franceschini Valeria , Errani Francesca , Sarli Giuseppe , Mandrioli Luciana 
Published: August 2017

BackgroundCutaneous squamous cell carcinoma (cSCC) is an uncommon disease affecting koi carp (Cyprinus carpio). Cutaneous papilloma (carp pox) is a benign epidermal proliferation reported in koi and has been shown to be caused by Cyprinid Herpesvirus 1 (CyHV1).Hypothesis/ObjectivesHistological, ultrastructural and molecular investigations were carried out aiming to investigate the aetiology of cSCC within archived tissue samples.AnimalsSurgical samples of masses located on the integument, fins and lips of 13 koi carp belonging to different private owners were included in this retrospective study.MethodsCyHV1 DNA and RNA presence were investigated in five cSCC formalin‐fixed paraffin‐embedded tissue samples to recognize CyHV1 presence and its replication activity.ResultsAll cases were histologically diagnosed as cSCC. The ultrastructural observations confirmed the squamous differentiation of neoplastic epithelial cells, which showed abundant tonofilament bundles and desmosomes. Although no virus particles were revealed ultrastructurally, the molecular investigation detected viral DNA in five epidemiologically unrelated cSCC. Viral transcript analysis revealed no evidence for viral replication in the tested cSCC, which could be consistent with latent infection.Conclusions and clinical importanceThese findings illustrate the frequent association of carp cSCC with CyHV1, although a direct cause–effect relationship cannot be established at this time. Therefore, surveillance programmes should take into account the suspected viral origin of cSCC to better inform prevention and control of CyHV1 in the future.
Process Control for Compression Systems
Authors: Kurz Rainer , Brun Klaus 
Published: August 2017

The paper discusses the interaction between a centrifugal compressor and the process, and as a result, the control requirements for centrifugal compressor packages. The focus is on variable speed, upstream and midstream applications. The impact of the interaction between system characteristics and compressor characteristics, both under steady state and transient conditions is explained. Also considered are concepts to optimize and control the units. Special attention is given to the issue of surge avoidance.
Additionally, the impact of the process and how the process dynamics interact with the compressor is analyzed, categorized, and explained.
Characterising the Influence of Impeller Exit Recirculation on Centrifugal Compressor Work Input
Authors: Stuart Charles , Spence Stephen , Filsinger Dietmar , Starke Andre , Kim Sung In 
Published: August 2017

Impeller recirculation is a loss which has long been considered in 1 D modelling, however the full extent of its impact on stage performance has not been analysed. Recirculation has traditionally been considered purely as a parasitic (or external) loss, i.e. one which absorbs work but does not contribute to total pressure rise across the stage. Having extensively analysed the impact of recirculation on the impeller exit flow field, it was possible to show that it has far reaching consequences beyond that of increasing total temperature. The overall aim of this package of work was to apply a much more physical treatment to the impact of impeller exit recirculation (and the aerodynamic blockage associated with it), and hence realise an improvement in the 1 D stage performance prediction of a number of turbocharger centrifugal compressors.
The factors influencing the presence and extent of this recirculation are numerous, requiring detailed investigations to successfully understand its sources and to characterise its extent. A combination of validated 3 D Computational Fluid Dynamics (CFD) data and gas stand test data for six automotive turbocharger compressor stages was employed to achieve this aim. In order to capture the variation of the blockage presented to the flow with both geometry and operating condition, an approach involving the impeller outlet to inlet area ratio and a novel flow coefficient term were employed. The resulting data permitted the generation of a single equation to represent the impeller exit blockage levels for the entire operating map of all six compressor stages under investigation.
With an understanding of the extent of the region of recirculating flow realised, and the key drivers leading to its creation identified, it was necessary to comprehend how the resulting blockage influenced compressor performance. Consideration was given to the impact on impeller work input through modification of the impeller exit velocity triangle, incorporating the introduction of the concept of an “aerodynamic meanline” to account for the reduction in the size of the active flow region due to the presence of blockage. The sensitivity of the stage to this change was then related back to the level of backsweep applied to the impeller. As a result of this analysis, the improvement in the 1 D performance prediction of the six compressor stages is demonstrated. In addition, a number of design recommendations are presented to ensure that the detrimental effects associated with the presence of impeller exit recirculation can be minimised.
Influence of Aerodynamic Mistuning and Aerodynamic Coupling on Vibration Behavior of Mistuned Small Radial Turbine Wheels
Authors: Hemberger David , Filsinger Dietmar , Bauer Hans-Jörg 
Published: August 2017

The study at hand analyzes the influence of aerodynamic mistuning and aerodynamic coupling on the vibration behavior of mistuned small radial turbine wheels. The aerodynamic mistuning is caused by angular non uniformity of the variable turbine guide vanes. Variable turbine guide vanes are state of the art in exhaust gas turbochargers for automotive diesel engines. Aerodynamic coupling describes the coupling of the turbine blades through the flow. It can influence the mistuned vibration behavior of the turbine wheel due to varying operation conditions, in which the turbine pressure ratio and the pressure distribution over the turbine wheel surface is changed.
It was analyzed whether the aerodynamic mistuning and aerodynamic coupling must be considered for small radial turbine wheel designs. The basis for this investigation were blade vibration measurements under standstill conditions with a laser vibrometer as well as blade vibration measurements during operation with a tip timing system. The mistuned turbine eigenforms were analyzed and compared at various ambient conditions using these measurement results.
By means of forced response calculations — unsteady 3D CFD and 3D FEA —, the influence of aerodynamic mistuning on the ideal tuned turbine was examined to be able to separate the aerodynamic mistuning from the mistuning of the structure. Furthermore, the superimposed effect of the aerodynamic mistuning and the mistuning of the structure on the turbine eigenforms and the amplitude amplification was analyzed using a mistuned 3D FE model and a population of samples with varying aerodynamic mistuning.
It was found, that the aerodynamic coupling and aerodynamic mistuning have a negligible effect on the mistuned vibration behavior for a small radial turbine with variable turbine guide vanes. These two parameters must not be considered when designing such a turbine wheel.
An Investigation of the Stability Enhancement of a Centrifugal Compressor Stage Using a Porous Throat Diffuser
Authors: Galloway Lee , Spence Stephen , Kim Sung In , Rusch Daniel , Vogel Klemens , Hunziker René 
Published: August 2017

The stable operating range of a centrifugal compressor stage of an engine turbocharger is limited at low mass flow rates by aerodynamic instabilities which can lead to the onset of rotating stall or surge. There have been many techniques employed to increase the stable operating range of centrifugal compressor stages. The literature demonstrates that there are various possibilities for adding special treatments to the nominal diffuser vane geometry, or including injection or bleed flows to modify the diffuser flow field in order to influence diffuser stability. One such treatment is the porous throat diffuser. Although the benefits of this technique have been proven in the existing literature, a comprehensive understanding of how this technique operates is not yet available.
This paper uses experimental measurements from a high pressure ratio compressor stage to acquire a sound understanding of the flow features within the vaned diffuser which affect the stability of the overall compression system and investigate the stabilising mechanism of the porous throat diffuser. The non-uniform circumferential pressure imposed by the asymmetric volute is experimentally and numerically examined to understand if this provides a preferential location for stall inception in the diffuser. The following hypothesis is confirmed: linking of the diffuser throats via the side cavity equalizes the diffuser throat pressure, thus creating a more homogeneous circumferential pressure distribution, which delays stall inception to lower flow rates. The results of the porous throat diffuser configuration are compared to a standard vaned diffuser compressor stage in terms of overall compressor performance parameters, circumferential pressure non-uniformity at various locations through the compressor stage and diffuser sub-component analysis. The diffuser inlet region was found to be the element most influenced by the porous throat diffuser and the stability limit is mainly governed by this element.
Heat Transfer in the Core Compressor Under Ice Crystal Icing Conditions
Authors: Bucknell Alexander , McGilvray Matthew , Gillespie David R. H. , Jones Geoff , Reed Alasdair , Buttsworth David R. 
Published: August 2017

It has been recognised in recent years that high altitude atmospheric ice crystals pose a threat to aircraft engines. Instances of damage, surge and shutdown have been recorded at altitudes significantly greater than those associated with supercooled water icing. It is believed that solid ice particles can accrete inside the core compressor, although the exact mechanism by which this occurs remains poorly understood.
Development of analytical and empirical models of the ice crystal icing phenomenon is necessary for both future engine design and this-generation engine certification. A comprehensive model will require the integration of a number of aerodynamic, thermodynamic and mechanical components. This paper studies one such component, specifically the thermodynamic and mechanical processes experienced by ice particles impinging on a warm surface.
Results are presented from an experimental campaign using a heated and instrumented flat plate. The plate was installed in the Altitude Icing Wind Tunnel (AIWT) at the National Research Council of Canada (NRC). This facility is capable of replicating ice crystal conditions at altitudes up to 9 km and Mach numbers up to 0.55 [1]. The heated plate is designed to measure the heat flux from a surface at temperatures representative of the early core compressor, under varying convective and icing heat loads.
Heat transfer enhancement was observed to rise approximately linearly with both total water content and particle diameter over the ranges tested. A Stokes number greater than unity proved to be a useful parameter in determining whether heat transfer enhancement would occur. A particle energy parameter was used to estimate the likelihood of fragmentation. Results showed that when particles were both ballistic and likely to fragment, heat transfer enhancement was independent of both Mach and Reynolds numbers over the ranges tested.
Boundary Layer Flashback in Premixed Hydrogen-Air Flames With Acoustic Excitation
Authors: Hoferichter Vera , Sattelmayer Thomas 
Published: August 2017

Lean premixed combustion is prevailing in gas turbines to minimize nitrogen oxide emissions. However, this technology bears the risk of flame flashback and thermoacoustic instabilities. Thermoacoustic instabilities induce velocity oscillations at the burner exit which, in turn, can trigger flame flashback.
This article presents an experimental study at ambient conditions on the effect of longitudinal acoustic excitation on flashback in the boundary layer of a channel burner. The acoustic excitation simulates the effect of thermoacoustic instabilities. Flashback limits are determined for different excitation frequencies characterizing intermediate frequency dynamics in typical gas turbine combustors (100–350 Hz). The excitation amplitude is varied from 0 to 36 % of the burner bulk flow velocity. For increasing excitation amplitude, the risk of flame flashback increases. This effect is strongest at low frequencies. For increasing excitation frequency the influence of the velocity oscillations decreases as the flame has less time to follow the changes in bulk flow velocity. Two different flashback regimes can be distinguished based on excitation amplitude. For low excitation amplitudes flashback conditions are reached if the minimum flow velocity in the excitation cycle falls below the flashback limit of unexcited unconfined flames. For higher excitation amplitudes, where the flame starts to periodically enter the burner duct, flashback is initiated if the maximum flow velocity in the excitation cycle is lower than the flashback limit of confined flames. Consequently, flashback limits of confined flames should also be considered in the design of gas turbine burners as a worst case scenario.