bluuebunny/crossref_metadata_2025 huggingface dataset:
Thinking of selection and widening access as complex and wicked problems
Authors: Cleland Jennifer A , Patterson Fiona , Hanson Mark D
Published: September 2018

Objectives

‘Wicked problems’ are complex in nature, have innumerable causes associated with multiple social environments and actors with unpredictable behaviour and outcomes, and are difficult to define or even resolve. This paper considers why and how the frameworks of complexity theory and wicked problems can help medical educators consider selection and widening access (WA) to medicine through fresh eyes to guide future policy and practice. We illustrate how ‘wickedity’ can frame the key issues in this area, and then address steps that education stakeholders might take to respond to and act on these issues.

Methods

We used the 10 properties of a wicked problem to frame common issues in the broad field of selection and WA in medicine. We drew heavily on literature from different disciplines, particularly education, and, through debate and reflection, agreed on the applicability of the theory for illuminating and potentially addressing outstanding issues in selection and WA.

Results

Framing medical school selection using the 10 properties of wicked problems is a means of shifting thinking from erroneous ‘simple’ solutions to thinking more contextually and receptively. The wicked problem framework positions selection as a multi‐causal, complex, dynamic, social problem and foregrounds stakeholders’ views and context as being highly relevant in medical school selection.

Conclusions

The wicked problem lens shifts thinking and action from seeking one elusive, objective truth to recognising the complexity of medical school selection, managing uncertainty, questioning and considering ‘issues’ associated with medical school selection more productively. Although there are criticisms of this framework, labelling medical selection as ‘wicked’ provides original insights and genuine reframing of the challenges of this important, and high profile, aspect of medical education. Doing so, in turn, opens the door to different responses than would be the case if selection and WA were simple and readily tamed.
Genome‐wide identification of genes directly regulated by ChvI and a consensus sequence for ChvI binding in Sinorhizobium meliloti
Authors: Ratib Nicole R. , Sabio Erich Y. , Mendoza Carolina , Barnett Melanie J. , Clover Sarah B. , Ortega Jesus A. , Dela Cruz Francesca M. , Balderas David , White Holly , Long Sharon R. , Chen Esther J.
Published: September 2018

ExoS/ChvI two‐component signaling in the nitrogen‐fixing α‐proteobacterium Sinorhizobium meliloti is required for symbiosis and regulates exopolysaccharide production, motility, cell envelope integrity and nutrient utilization in free‐living bacteria. However, identification of many ExoS/ChvI direct transcriptional target genes has remained elusive. Here, we performed chromatin immunoprecipitation followed by microarray analysis (chIP‐chip) to globally identify DNA regions bound by ChvI protein in S. meliloti. We then performed qRT‐PCR with chvI mutant strains to test ChvI‐dependent expression of genes downstream of the ChvI‐bound DNA regions. We identified 64 direct target genes of ChvI, including exoY, rem and chvI itself. We also identified ChvI direct target candidates, like exoR, that are likely controlled by additional regulators. Analysis of upstream sequences from the 64 ChvI direct target genes identified a 15 bp‐long consensus sequence. Using electrophoretic mobility shift assays and transcriptional fusions with exoY, SMb21440, SMc00084, SMc01580, chvI, and ropB1, we demonstrated this consensus sequence is important for ChvI binding to DNA and transcription of ChvI direct target genes. Thus, we have comprehensively identified ChvI regulon genes and a ‘ChvI box’ bound by ChvI. Many ChvI direct target genes may influence the cell envelope, consistent with the critical role of ExoS/ChvI in growth and microbe–host interactions.
Collective action and provider classification in the sharing economy
Authors: Newlands Gemma , Lutz Christoph , Fieseler Christian
Published: September 2018

Conditions in the sharing economy are often favourably designed for consumers and platforms but entail new challenges for the labour side, such as substandard social‐security and rigid forms of algorithmic management. Since comparatively little is known about how providers in the sharing economy make their voices heard collectively, we investigate their opinions and behaviours regarding collective action and perceived solidarities. Using cluster analysis on representative data from across 12 European countries, we determine five distinct types of labour‐activists, ranging from those opposed to any forms of collective action to those enthusiastic to organise and correct perceived wrongs. We conclude by conjecturing that the still‐ongoing influx of new providers, the difficulty of organising in purely virtual settings, combined with the narrative of voluntariness of participation and hedonic gratifications might be responsible for the inaction of large parts of the provider base in collectivist activities.
Changes to the core and flanking sequences of G‐box elements lead to increases and decreases in gene expression in both native and synthetic soybean promoters
Authors: Zhang Ning , McHale Leah K. , Finer John J.
Published: September 2018

Cis‐regulatory elements in promoters are major determinants of binding specificity of transcription factors (TFs) for transcriptional regulation. To improve our understanding of how these short DNA sequences regulate gene expression, synthetic promoters consisting of both classical (CACGTG) and variant G‐box core sequences along with different flanking sequences derived from the promoters of three different highly expressing soybean genes, were constructed and used to regulate a green fluorescent protein (gfp) gene. Use of the classical 6‐bp G‐box provided information on the base level of GFP expression while modifications to the 2–4 flanking bases on either side of the G‐box influenced the intensity of gene expression in both transiently transformed lima bean cotyledons and stably transformed soybean hairy roots. The proximal 2‐bp sequences on either flank of the G‐box significantly affected G‐box activity, while the distal 2‐bp flanking nucleotides also influenced gene expression albeit with a decreasing effect. Manipulation of the upstream 2‐ to 4‐bp flanking sequence of a G‐box variant (GACGTG), found in the proximal region of a relatively weak soybean glycinin promoter, significantly enhanced promoter activity using both transient and stable expression assays, if the G‐box variant was first converted into a classical G‐box (CACGTG). In addition to increasing our understanding of regulatory element composition and structure, this study shows that minimal targeted changes in native promoter sequences can lead to enhanced gene expression, and suggests that genome editing of the promoter region can result in useful and predictable changes in native gene expression.
A Pilot Observational Study of Environmental Summertime Health Risk Behavior in Central Brisbane, Queensland: Opportunities to Raise Sun Protection Awareness in Australia's Sunshine State
Authors: Dexter Ben , King Rachel , Harrison Simone L. , Parisi Alfio V. , Downs Nathan J.
Published: September 2018

Melanoma skin cancer rates in Queensland exceed the national Australian incidence rate, which together with New Zealand are recognized as the world's highest. Incidence is especially high among younger members of the population. In this study, the sun‐protective behaviors of urban Queenslanders (n = 752) going about their day‐to‐day activities during a midweek noon time hourly period were observed on a summer's day in central Brisbane (27.47°S, 153.03°E), Australia. Observed sun protection practices were poor, given the time of year and peak solar noon period of the study. More individuals (n = 249; 33.1%) were seen wearing sunglasses than a hat (n = 101; 13.4%). Ninety‐three individuals were actively engaging with mobile phones (phone in hand). A further 231 individuals (30.7%) were observed with a mobile phone on them. Opportunities to modify group behavior based on mobile phone sun protection notifications and to engage with “at risk” members of the Queensland population are considered from the variable codependencies examined in this study, including the influence of social group size, observed sun protection and mobile phone use. Our preliminary findings suggest that mobile phones provide an underutilized opportunity for delivering tailored skin cancer prevention messaging.
Reliable Flexibility Design of Supply Chains Via Extended Probabilistic Expanders
Authors: Shen Hao , Liang Yong , Shen Zuo‐Jun Max , Teo Chung‐Piaw
Published: September 2018

It is well‐known that adding a little flexibility to the right place is an effective strategy to improve the performance of operations in the face of demand uncertainties, to ensure high level of capacity utilization. However, given that system disruptions are ubiquitous, the legacy flexibility designs may perform poorly under disruptions to supply or capacity installations. In this study, we focus on the design of reliable and sparse flexibility structures that consistently meet a reasonable performance criterion under disruptions to both demand and supply. Specifically, we propose a class of structures termed as extended probabilistic expanders, based on the conjecture that the expansion property, rather than the global connectivity, is critical to good performance of the structures. We prove that for a system with n retailers, essentially only O( n) supply routes between suppliers and retailers are necessary to ensure good performance under disruption. In addition, we present an efficient randomized algorithm to construct extended probabilistic expanders, and demonstrate that the construction yields very good structure with the least number of edges asymptotically. We also investigate an extension to systems with structural constraints. Numerical results demonstrate that our design has not only a wide range of applications, but also better performance than a variety of known structures.
Insect meals in fish nutrition
Authors: Nogales‐Mérida Silvia , Gobbi Paola , Józefiak Damian , Mazurkiewicz Jan , Dudek Krzysztof , Rawski Mateusz , Kierończyk Bartosz , Józefiak Agata
Published: September 2018

Different studies have shown that insect meals can partially or completely replace the fish and soya bean meals that are commonly used in aquaculture. However, information is lacking on the amino acid and fatty acid contents and digestibility of different insect meals. Moreover, we evaluated different proportions of insect diets and determined how these affected the nutritional values of insect meals. Our purpose was to clarify these aspects and consider the availability of protein, amino acids, lipids and fatty acids in insect meals in fish nutrition. Generally, insect meals have higher indispensable amino acid contents than other meal types, with contents closely related to those in fish meal. Insect meal can be an important source of essential amino acids such as methionine, with contents ranging between 0.47 and 4.03 g 100 g−1 sample. These values are higher than those reported for other animal and plant meals. In addition, insects are also good sources of lipids and fatty acids, and the amounts and types of fatty acids vary according to the species, stage of development and type of feed. Moreover, the additional nutritional value of insect meal includes compounds such as chitin, which is primarily considered a fibre but also contains nitrogen and amino acids. Insect peptides with activity against pathogenic microflora provide secondary biological effects, which may significantly improve animal health.
Does the distinction between gross and value‐added exports matter? An empirical investigation of export elasticities
Authors: Ceglowski Janet
Published: September 2018

This study uses bilateral U.S. export data from the OECD’s Trade in Value‐Added database to estimate and compare elasticities for three distinct export measures: conventional measures of gross exports, domestic value added in gross exports, and value‐added exports. It finds little evidence of significant differences in the income elasticities across the three export measures or in the price elasticities of gross exports and domestic value added in gross exports. However it finds a significantly higher price elasticity for value‐added exports, suggesting that conventional price elasticity estimates may underestimate the impact of a real dollar depreciation on U.S. exports of value added.
The statistical reconciliation of time series of accounts between two benchmark revisions
Authors: Chen Baoline , Di Fonzo Tommaso , Howells Thomas , Marini Marco
Published: September 2018

The 2003–2007 U.S. annual input–output accounts, GDP‐by‐industry accounts, and expenditure‐based GDP are reconciled with the 2002 and 2007 quinquennial benchmarks and all contemporaneous constraints of the input–output accounts for the in‐between years. The reconciliation is performed at a very detailed level (six‐digit NAICS) according to feasible statistical procedures able to deal with very large systems of accounts. Our objective is to adjust the preliminary levels of the annual 2003–2007 series such that they are consistent with the quinquennial benchmarks available, fulfill all the accounting relationships for any given year, and show movements that are as close as possible to the preliminary information. We use a simultaneous least‐squares procedure based on the proportional first difference criterion, a well known movement preservation principle proposed by Denton. We evaluate the possible adoption of (i) a pure proportional (PROP) adjustment for small series and series with both negative and positive values that deteriorate the meaningfulness of growth rates, and (ii) a priori assumptions for groups of variables according to their different reliabilities, where this can reasonably be imposed.
Teaching human factors: a near‐peer approach
Authors: Aldridge Matthew J , Purdell‐Lewis Jeremy
Published: September 2018

Background

An understanding of human factors and ergonomics (HFE) is critical for optimal team performance, and is an important component of the postgraduate medical curriculum. This training is often delivered by senior clinicians with experience of using and teaching HFE concepts. A lack of availability of these experienced tutors can be a constraint on training provision.

Context

A near‐peer tutor (NPT) approach was used to deliver a classroom‐based HFE course to postgraduate doctors, supported by a tutor handbook. We aimed to compare feedback from this course with a previous course taught by experienced tutors.

Methods

Learners (n = 21) attending this course were divided into small groups, with one NPT per group. Each group viewed three video reconstructions of incidents from health care and other industries, followed by a structured discussion. Learners were encouraged to recognise concepts from HFE, and to develop changes to their own practice. The NPTs were guided through the session by a tutor handbook, which they received in advance.

Human factors and ergonomics training is associated with a significant decrease in error

Results

Initial and 2‐month feedback was extremely positive, with Likert scores of 5/5 for Organisation, Content, Teaching Methods and Overall Impression. This was significantly (p < 0.05) better than feedback from a previous HFE course with senior tutors. Median NPT confidence ratings before and after receiving the handbook were 4/10 and 8/10, respectively.

Conclusions

These results support the use of NPTs in delivering HFE training to postgraduate doctors. Self‐reported confidence is increased by providing a handbook with discussion prompts. Training in HFE does not require senior tutors with significant clinical commitments, and can be provided to a high standard by NPTs.
Vascular conspicuity differs among injection protocols and scanner types for canine multiphasic abdominal computed tomographic angiography
Authors: Thierry Florence , Chau Jennifer , Makara Mariano , Specchi Swan , Auriemma Edoardo , Longo Maurizio , Handel Ian , Schwarz Tobias
Published: September 2018

Multiphasic multidetector computed tomographic angiography is a standard diagnostic test for canine abdominal vascular disorders. Three imaging protocols have been previously described. The test‐bolus protocol allows precise timing but can be time consuming to perform. Bolus‐tracking software is fast and easy to use but can be problematic for exact timing of vascular phases. A recently described fixed‐injection‐duration protocol is not influenced by body weight and provides a wider temporal window for arterial acquisitions. Objectives of this retrospective and prospective, multicentric, method comparison study were to determine which of the three multidetector computed tomographic angiography protocols allows best vascular conspicuity of the canine abdomen and to assess the influence of different multidetector computed tomography (CT) scanners on study quality. Triple‐phase multidetector computed tomographic angiography canine abdominal studies from 30 dogs were retrospectively retrieved from three different institutions. Each institution performed one of the three computed tomographic angiography protocols (4‐row and 16‐row multidetector CT). Prospectively, the three protocols were also acquired with similar conditions on a 64‐row MDCT in 21 dogs. Main abdominal vessels were scored by blinded readers for each phase. The fixed‐injection‐duration protocol had the best combined arterial and portal vascular conspicuity on scanners of limited speed, while the test‐bolus protocol provided the best overall vascular conspicuity on 64‐row multidetector CT scanner. The quality of arterial studies performed on 64‐row MDCT scanner was improved compared to the ones performed on four‐ to 16‐row multidetector CT scanners. Findings supported the fixed‐injection‐duration protocol as the best compromise between an ideal portal vascular enhancement and an easily reproducible protocol on scanners with low and high number of detector rows.
Language and Literature Education in Azerbaijan and Turkey
Authors: Eskimen Ayşe Derya
Published: September 2018

Turkish world geography is a vast geography. In its broadest sense, it expands from Balkans in the west to the Pacific Ocean in the east; from the Arctic Ocean in the North to Tibet in the South. The subject of our study is Azerbaijan which is one of the independent states in this geography. In the study, similarities and differences of Turkish and Azerbaijan education system, language-literature education, curriculum, course books were analysed. Azerbaijan was chosen for the study since it is akin to Turkey in the sense of language and geography and it also takes the head in Turkish world in education and culture. In the collection of data, document review method was used and in the light of information acquired, positive aspects of both countries were used.
The Effect of Relative Age on Some Performance Characteristics in Young Volleyball Players
Authors: Akarçeşme Cengiz , Aytar Sinem Hazır
Published: September 2018

It has been evaluated in the literature that different maturation levels exist in the same chronological age and this may be an advantage for athletic performance. The aim of this study was to examine the performance characteristics of young male and female volleyball players in the same chronological age according to their relative age.A total of 536 athletes who were 14 years old and similar training age, 238 male and 298 female subjects participated in this study. Relative age was determined by quitting the quartile of the year starting from January. Explosive strength (counter movement and squat jumps), anaerobic strength and capacity (Wingate test), aerobic capacity (20m shuttle run) and speed (5m and 10m sprint) were measured. 2x4 ANOVA was used to determine the differences between gender and relative age groups, and Bonferroni test was used to determine the differences between the quarters of the year. The significance level of all statistical procedures was accepted as 0.05.The distribution of volleyball players in the quarters was 47.9%, 27.7%, 17.6%, 6.7% for males, 39.9%, 29.5%, 17.4% and 13.1% for females respectively. The differences between the genders in all variables were statistically significant (p<0.05). Relative age effect (RAE) was not significant in all variables examined as performance parameters (p>0.05).As a result of this study it was found that both female and male volleyball players were mostly born in the first quarter of the year. On the other hand, relative age was not a distinctive effect on performance variables of young volleyball players in the same chronological age.
Postnatal deficiency of ADAMTS1 ameliorates thoracic aortic aneurysm and dissection in mice
Authors: Wang Shanshan , Liu Yuting , Zhao Guizhen , He Li , Fu Yi , Yu Changan , Wang Zhizhi , Zhao Tingting , Cao Fan , Gao Yanxiang , Kong Wei , Zheng Jingang
Published: September 2018

New Findings

What is the central question of this study?

Thoracic aortic aneurysm and dissection (TAAD) is characterized by extracellular matrix remodelling and an inflammatory response. Evidence suggests that ADAMTS1 is closely associated with TAAD development, but whether it contributes to the pathophysiology of TAAD remains unknown.

What is the main finding and its importance?

We generated inducible postnatal ADAMTS1 knockout mice and found that ADAMTS1 deficiency attenuated β‐aminopropionitrile‐dependent TAAD formation and rupture. Furthermore, ADAMTS1 deficiency suppressed neutrophil and macrophage infiltration by inhibiting inflammatory cytokine levels and macrophage migration during the early stage of β‐aminopropionitrile‐induced TAAD. ADAMTS1 could be a new therapeutic target for TAAD.

Thoracic aortic aneurysm and dissection (TAAD), as a life‐threatening cardiovascular disease, is characterized by extracellular matrix remodelling and an inflammatory response. A disintegrin and metalloproteinase with thrombospondin motifs 1 (ADAMTS1) is an inflammation‐related protein that is able to degrade extracellular matrix proteins in arteries. Herein, we investigated whether ADAMTS1 contributes to the pathophysiology of TAAD in mice. Using the mouse model of β‐aminopropionitrile (BAPN)‐induced TAAD, we found that ADAMTS1 expression was upregulated beginning in the early stage of TAAD development and localized predominantly in the aortic adventitia. ADAMTS1‐floxed mice and whole‐body tamoxifen‐inducible ADAMTS1 knockout mice (ADAMTS1flox/flox Ubc‐CreERT2+, ADAMTS1 KO) were generated to investigate the direct causal role of ADAMTS1 in TAAD development. The incidence and rupture rates of BAPN‐induced TAAD in ADAMTS1 KO mice were significantly lower than those in ADAMTS1flox/flox mice (45.5 versus 81.8% and 18.2 versus 42.4%, respectively). Aortas from BAPN‐treated ADAMTS1flox/flox mice displayed profound destruction of the elastic lamellae, abundant neutrophil and macrophage accumulation in the adventitia, obviously increased neutrophil proportions in peripheral blood and significantly increased expression of inflammatory factors in the early stage of TAAD induction, all of which were markedly suppressed in ADAMTS1 KO mice. Furthermore, ADAMTS1‐deficient macrophages exhibited abrogated migration capacity both in vivo and in vitro. In conclusion, ADAMTS1 plays a crucial role in postnatal TAAD formation and rupture by regulating inflammatory responses, suggesting that ADAMTS1 might be a new therapeutic target for TAAD.
Conceptual Flutter Analysis of Labyrinth Seals Using Analytical Models—Part I: Theoretical Support
Authors: Corral Roque , Vega Almudena
Published: September 2018

A simple nondimensional model to describe the flutter onset of labyrinth seals is presented. The linearized mass and momentum integral equations for a control volume which represents the interfin seal cavity, retaining the circumferential unsteady flow perturbations created by the seal vibration, are used. First, the downstream fin is assumed to be choked, whereas in a second step the model is generalized for unchoked exit conditions. An analytical expression for the nondimensional work-per-cycle is derived. It is concluded that the stability of a two-fin seal depends on three nondimensional parameters, which allow explaining seal flutter behavior in a comprehensive fashion. These parameters account for the effect of the pressure ratio, the cavity geometry, the fin clearance, the nodal diameter (ND), the fluid swirl velocity, the vibration frequency, and the torsion center location in a compact and interrelated form. A number of conclusions have been drawn by means of a thorough examination of the work-per-cycle expression, also known as the stability parameter by other authors. It was found that the physics of the problem strongly depends on the nondimensional acoustic frequency. When the discharge time of the seal cavity is much greater than the acoustic propagation time, the damping of the system is very small and the amplitude of the response at the resonance conditions is very high. The model not only provides a unified framework for the stability criteria derived by Ehrich (1968, “Aeroelastic Instability in Labyrinth Seals,” ASME J. Eng. Gas Turbines Power, 90(4), pp. 369–374) and Abbot (1981, “Advances in Labyrinth Seal Aeroelastic Instability Prediction and Prevention,” ASME J. Eng. Gas Turbines Power, 103(2), pp. 308–312), but delivers an explicit expression for the work-per-cycle of a two-fin rotating seal. All the existing and well-established engineering trends are contained in the model, despite its simplicity. Finally, the effect of swirl in the fluid is included. It is found that the swirl of the fluid in the interfin cavity gives rise to a correction of the resonance frequency and shifts the stability region. The nondimensionalization of the governing equations is an essential part of the method and it groups physical effects in a very compact form. Part I of the paper details the derivation of the theoretical model and draws some preliminary conclusions. Part II of the corresponding paper analyzes in depth the implications of the model and outlines the extension to multiple cavity seals.
Secondary Flows in Low-Pressure Turbines Cascades: Numerical and Experimental Investigation of the Impact of the Inner Part of the Boundary Layer
Authors: Giovannini Matteo , Rubechini Filippo , Marconcini Michele , Simoni Daniele , Yepmo Vianney , Bertini Francesco
Published: September 2018

Due to the low level of profile losses reached in low-pressure turbines (LPT) for turbofan applications, a renewed interest is devoted to other sources of loss, e.g., secondary losses. At the same time, the adoption of high-lift profiles has reinforced the importance of these losses. A great attention, therefore, is dedicated to reliable prediction methods and to the understanding of the mechanisms that drive the secondary flows. In this context, a numerical and experimental campaign on a state-of-the-art LPT cascade was carried out focusing on the impact of different inlet boundary layer (BL) profiles. First of all, detailed Reynolds Averaged Navier-Stokes (RANS) analyzes were carried out in order to establish dependable guidelines for the computational setup. Such analyzes also underlined the importance of the shape of the inlet BL very close to the endwall, suggesting tight requirements for the characterization of the experimental environment. The impact of the inlet BL on the secondary flow was experimentally investigated by varying the inlet profile very close to the endwall as well as on the external part of the BL. The effects on the cascade performance were evaluated by measuring the span-wise distributions of flow angle and total pressure losses. For all the inlet conditions, comparisons between Computational Fluid Dynamics (CFD) and experimental results are discussed. Besides providing guidelines for a proper numerical and experimental setup, the present paper underlines the importance of a detailed characterization of the inlet BL for an accurate assessment of the secondary flows.
On the Influence of Fuel Stratification and Its Control on the Efficiency of the Shockless Explosion Combustion Cycle
Authors: Rähse Tim S. , Stathopoulos Panagiotis , Schäpel Jan-Simon , Arnold Florian , King Rudibert
Published: September 2018

Constant volume combustion (CVC) cycles for gas turbines are considered a very promising alternative to the conventional Joule cycle and its variations. The reason is the considerably higher thermal efficiency of these cycles, at least for their ideal versions. Shockless explosion combustion (SEC) is a method to approximate CVC. It is a cyclic process that consists of four stages, namely wave propagation, fuel injection, homogeneous auto-ignition, and exhaust. A pressure wave in the combustion chamber is used to realize the filling and exhaust phases. During the fuel injection stage, the equivalence ratio is controlled in such a way that the ignition delay time of the mixture matches its residence time in the chamber before auto-ignition. This means that the fuel injected first must have the longest ignition delay time, and thus forms the leanest mixture with air. By the same token, fuel injected last must form the richest mixture with air (assuming that a rich mixture leads to a small ignition delay). The total injection time is equal to the time that the wave needs to reach the open combustor end and return as a pressure wave to the closed end. Up to date, fuel stratification has been neglected in thermodynamic simulations of the SEC cycle. The current work presents its effect on the thermal efficiency of the cycle and on the exhaust conditions (pressure, temperature, and Mach number) of shockless explosion combustion chambers. This is done by integrating a fuel injection control algorithm in an existing computational fluid dynamics code. The capability of this algorithm to homogenize the auto-ignition process by improving the injection process has been demonstrated in past experimental studies of the SEC. The numerical code used for the simulation of the combustion process is based on the time-resolved 1D-Euler equations with source terms obtained from a detailed chemistry model.
Stress-State, Temperature, and Strain Rate Dependence of Vintage ASTM A7 Steel
Authors: Brauer S. A. , Whittington W. R. , Rhee H. , Allison P. G. , Dickel D. E. , Crane C. K. , Horstemeyer M. F.
Published: September 2018

The structure–property relationships of a vintage ASTM A7 steel is quantified in terms of stress state, temperature, and strain rate dependence. The microstructural stereology revealed primary phases to be 15.8% ± 2.6% pearlitic and 84.2% ± 2.6 ferritic with grain sizes of 13.3 μm ± 3.1 μm and 36.5 μm ± 7.0 μm, respectively. Manganese particle volume fractions represented 0.38–1.53% of the bulk material. Mechanical testing revealed a stress state dependence that showed a maximum strength increase of 85% from torsion to tension and a strain rate dependence that showed a maximum strength increase of 38% from 10−1 to 103 s−1at 20% strain. In tension, a negative strain rate sensitivity (nSRS) was observed in the quasi-static rate regime yet was positive when traversing from the quasi-static rates to high strain rates. Also, the A7 steel exhibited a significant ductility reduction as the temperature increased from ambient to 573 K (300 °C), which is uncommon for metals. The literature argues that dynamic strain aging (DSA) can induce the negative strain rate sensitivity and ductility reduction upon a temperature increase. Finally, a tension/compression stress asymmetry arises in this A7 steel, which can play a significant role since bending is prevalent in this ubiquitous structural material. Torsional softening was also observed for this A7 steel.
Experimental Investigation of Vertical Marine Surface Icing in Periodic Spray and Cold Conditions
Authors: Dehghani-Sanij Alireza , Mahmoodi Maziyar , Dehghani Saeed-Reza , Muzychka Yuri S. , Naterer Greg F.
Published: September 2018

In this paper, the ice load accumulated on a vertical plate of marine platforms during periodic spray icing in a cold room was investigated experimentally. The mass and thickness of ice formation on the plate along with several parameters such as relative humidity, the front and back surface temperatures of the vertical plate, initial temperature of water, and the spray mass flux impinging on the plate were measured and discussed. Analysis of variance (ANOVA), which is a statistical data analysis method, was utilized to interpret the contribution of the investigated parameters during the icing experiments, comparing the effect of each parameter and their interactions on the quantity of ice accumulated on the vertical plate. The primary analysis of the empirical results illustrates that the ambient temperature, airflow velocity, the distance between the fan and the plate, salinity and the timing of spray events have influences in the icing intensity and the amount of ice formation on the vertical plate. The errors between the average ice thicknesses obtained from two different experimental approaches were from 5 to 20%. For the saline ice formation, the temperature difference between the front and back of the vertical plate was greater than that of the pure ice formed during the spray icing event. The primary experimental results alongside the ANOVA analysis verified that airflow velocity is the most effective parameter, with a high level of interaction for time and temperature.
Nonlinear Computational Welding Mechanics for Large Structures
Authors: Ikushima Kazuki , Shibahara Masakazu
Published: September 2018

In the construction of thin plate steel structures, including ships, welding is widely used to join parts. Welding inevitably causes deformation in thin plate structures, which may cause various problems. In the present study, an analysis method is developed to realize the prediction of deformation during the construction of large-scale structures based on the thermal elastic plastic analysis method. The developed method uses the idealized explicit finite element method (IEFEM), which is a high-speed thermal elastic plastic analysis method, and an algebraic multigrid method (AMG) is also introduced to the IEFEM in order to realize an efficient analysis of large-scale thin plate structures. In order to investigate the analysis accuracy and the performance of the developed method, the developed method is applied to the analysis of deformation on the welding of a simple stiffened structure. The developed method is then applied to the prediction of welding deformation in the construction of a ship block. The obtained results indicate that the developed method has approximately the same analysis accuracy as the conventional method, and the computational speed of the developed method is dramatically faster than that of the conventional method. The developed method can analyze the welding deformation in the construction of the ship block structure which consists of more than 10 million degrees-of-freedom and is difficult to solve by the conventional method.
Etching of glass, silicon, and silicon dioxide using negative ionic liquid ion sources
Authors: Xu Tiantong , Tao Zhi , Lozano Paulo C.
Published: September 2018

Ionic liquid ion sources have been proposed as a new type of ion source for focused ion beam and broad ion beam applications. In this paper, the ionic liquid EMI-BF4 (1-ethyl-3-methylimidazolium tetrafluoroborate) was used as an ion source to generate negatively charged ions and irradiate glass (Pyrex 7740), silicon, and silicon dioxide targets. The results indicate that negative EMI-BF4 ion beams can prevent issues related to surface charge accumulation on dielectric substrates, achieving etching selectivities of SiO2:Si of at least 1.55. The etching rate increases on glass, silicon, and silicon dioxide at higher ion landing energies. It is shown that the negative EMI-BF4 beam has a higher yield than traditional metal gallium ion beams, likely due to the chemical reactivity of fluorine radicals. This effect is also noticeable when compared to results using positive EMI-BF4 beams.
Differences in cue weights for speech perception are correlated for individuals within and across contrasts
Authors: Clayards Meghan
Published: September 2018

Speech perception requires multiple acoustic cues. Cue weighting may differ across individuals but be systematic within individuals. The current study compared individuals' cue weights within and across contrasts. Forty-two listeners performed a two-alternative forced choice task for four out of five sets of minimal pairs, each varying orthogonally in two dimensions. Individuals' cue weights within a contrast were positively correlated for bet-bat, Luce-lose, and sock-shock, but not for bog-dog and dear-tear. Importantly, individuals' cue weights were also positively correlated across contrasts. This indicates that some individuals are better able to extract and use phonetic information across different dimensions.
One, two, three—how many cells for me?
Authors: Henrickson Sarah E.
Published: September 2018

An alternate strategy is described for enumerating peripheral immune cells in health and disease by epigenetic quantitative PCR.
Transmission Surveillance for Antimicrobial-Resistant Organisms in the Health System
Authors: Pitout Johann D. D.
Published: September 2018

Surveillance of antibiotic resistance involves the collection of antibiotic susceptibility patterns undertaken by clinical microbiology laboratories on bacteria isolated from clinical specimens. Global surveillance programs have shown that antibiotic resistance is a major threat to the public at large and play a crucial role in the development of enhanced diagnostics as well as potential vaccines and novel antibiotics with activity against antimicrobial-resistant organisms. This review focuses primarily on examples of global surveillance systems. Local, national, and global integrated surveillance programs with sufficient data linkage between these schemes, accompanied by enhanced genomics and user-friendly bioinformatics systems, promise to overcome some of the stumbling blocks encountered in the understanding, emergence, and transmission of antimicrobial-resistant organisms.
Causality in Biological Transmission: Forces and Energies
Authors: Baquero Fernando
Published: September 2018

Transmission is a basic process in biology that can be analyzed in accordance with information theory. A sender or transmitter located in a particular patch of space is the source of the transmitted object, the message. A receiver patch interacts to receive the message. The “messages” that are transmitted between patches (eventually located in different hierarchical biological levels) are “meaningful” biological entities (biosemiotics).
cis
-acting transmission occurs when unenclosed patches acting as emitter and receiver entities of the same hierarchical level are linked (frequently by a vehicle) across an unfit space;
trans
-acting transmission occurs between biological individuals of different hierarchical levels, embedded within a close external common limit. To understand the causal frame of transmission events, we analyze the ultimate, but most importantly also the proximate, causes of transmission. These include the repelling, centrifugal “forces” influencing the transmission (emigration) and the attractive, centripetal “energies” involved in the reception (immigration). As transmission is a key process in evolution, creating both genetic-embedded complexity-diversity (
trans
-acting transmission, as introgression), and exposure to novel and alternative patches-environments (
cis
-acting transmission, as migration), the causal frame of transmission shows the
cis
-evolutionary and
trans
-evolutionary dimensions of evolution.
Age-dependent changes in GI physiology and microbiota: time to reconsider?
Authors: An Ran , Wilms Ellen , Masclee Ad A M , Smidt Hauke , Zoetendal Erwin G , Jonkers Daisy
Published: September 2018

Our life expectancy is increasing, leading to a rise in the ageing population. Ageing is associated with a decline in physiological function and adaptive capacity. Altered GI physiology can affect the amount and types of nutrients digested and absorbed as well as impact the intestinal microbiota. The intestinal microbiota is considered a key player in our health, and a variety of studies have reported that microbiota composition is changing during ageing. Since ageing is associated with a decline in GI function and adaptive capacity, it is crucial to obtain insights into this decline and how this is related to the intestinal microbiota in the elderly. Hence, in this review we focus on age-related changes in GI physiology and function, changes of the intestinal microbiota with ageing and frailty, how these are associated and how intestinal microbiota-targeted interventions may counteract these changes.
DHA supplementation improves cognitive function via enhancing Aβ-mediated autophagy in Chinese elderly with mild cognitive impairment: a randomised placebo-controlled trial
Authors: Zhang Yan-Ping , Lou Yinyin , Hu Jing , Miao Rujuan , Ma Fei
Published: September 2018

Background

Higher docosahexaenoic acid (DHA) intake is inversely correlated with relative risk of Alzheimer’s disease. The potential benefits of DHA supplementation in people with mild cognitive impairment (MCI) have not been fully examined.

Objective

Our study aimed to assess the effect of a 24-month DHA supplementation on cognitive function and amyloid beta (Aβ)-mediated autophagy in elderly subjects with MCI.

Methods

This was a randomised, double-blind, placebo-controlled trial in Tianjin, China. A total of 240 individuals with MCI were identified and randomly divided into intervention (DHA 2 g/day, n=120) and control (corn oil as placebo, n=120) groups. Cognitive function and blood Aβ-related biomarkers were measured at baseline, 6, 12, 18 and 24 months. Data were analysed using generalised estimating equation.

Results

A total of 217 participants (DHA: 109, placebo: 108) completed the trial. During the follow-up, scores of full-scale IQ, verbal IQ and subdomains of information and digit span were significantly higher in the intervention group than the convention group (p<0.05). In the intervention group, blood Aβ-42 level and expression of Aβ protein precursor mRNA were decreased (p<0.05), while Beclin-1 and LC3-II levels and expression of LC3-II mRNA were increased (p<0.05).

Conclusion

Daily oral DHA supplementation (2 g/day) for 24 months may improve cognitive function and change blood biomarker-related Aβ-mediated autophagy in people with MCI. Larger longer-term confirmatory studies are warranted.

Trial registration number

ChiCTR-IOR-15006058.
Crossing Y-Solitaire thrombectomy as a rescue treatment for refractory acute occlusions of the middle cerebral artery
Authors: Aydin Kubilay , Barburoglu Mehmet , Oztop Cakmak Ozgur , Yesilot Nilufer , Vanli Ebru Nur Yavuz , Akpek Sergin
Published: September 2018

Background

Mechanical thrombectomy using a stent retriever has become the standard of care for acute large-vessel occlusions in the anterior circulation. Clots that are refractory to single stent retriever thrombectomy remain a challenge for neurointerventionalists.

Objective

To assess the efficacy and safety of double stent retriever (crossing Y-Solitaire) thrombectomy as a rescue treatment for acute middle cerebral artery (MCA) occlusions that are refractory to single stent retriever thrombectomy.

Methods

We retrospectively reviewed the databases of our hospitals to identify patients who presented with an acute MCA occlusion and were treated with crossing Y-Solitaire thrombectomy. The angiographic (Thrombolysis in Cerebral Infarction (TICI) scale) and clinical outcomes (National Institutes of Health Stroke Scale (NIHSS) and modified Rankin Scale (mRS) scores) and complications were assessed.

Results

Ten patients were included in the study. The median initial NIHSS score and Alberta Stroke Program Early CT Score (ASPECTS) were 19.0 and 9.6, respectively. Crossing Y-Solitaire thrombectomy was performed as a rescue technique after unsuccessful single Solitaire thrombectomy passes in all cases. Successful recanalization (TICI 2b/3) was achieved in 8 (80%) patients. We observed asymptomatic reperfusion hemorrhages in 2 (20%) patients. No procedural related complications were seen other than reversible vasospasms in 5 (50%) patients. Sixty percent of the patients had a mRS score of between 2 and 0 at 90 days after the procedure. There was no mortality.

Conclusion

Crossing Y-Solitaire thrombectomy seems to be an effective and safe alternative rescue technique to treat refractory MCA bifurcation occlusions that are refractory to standard thrombectomy procedures.
Barriers and motivators towards a national final year assessment in the United Kingdom and the Republic of Ireland for veterinary undergraduates
Authors: Pooley Fay , Wapenaar Wendela
Published: September 2018

In the final year of the course schools assess students to ensure a minimum level of knowledge and skills is achieved before graduation as a veterinary surgeon. Across the universities, different styles and combinations of assessments are used. A national assessment could provide a solution to maintain quality and potential employability of veterinary surgeons. The aim of this study was to identify barriers and motivators of veterinary educators from all veterinary schools in the UK and the Republic of Ireland towards a national assessment. Semistructured interviews were conducted with 16 academic staff members. Mixed opinions were expressed and many barriers as well as motivators were voiced. Four main themes were: harmonisation and benchmarking, confidence in quality, practical feasibility and stakeholder perspectives. The study identified a positive attitude towards a national assessment, particularly around improved quality and standards. However, the practical feasibility was perceived as a significant barrier for implementation. Before making changes to current assessments it is important to further research the barriers identified to confirm representativeness and to acquire evidence to accept or refute the perceived limitations.
Ian Frank Keymer
Authors: Wells Gerald , Malley Dermod , Simpson Vic
Published: September 2018

A country boy who became, and remained, a countryman at heart. He was fascinated by diseases of wildlife and collaborated with others to publish widely on the topic.
Friedmann–Robertson–Walker (FRW) cosmological model in the present perspective
Authors: Goswami G.K.
Published: September 2018

In this paper, we have presented a cosmological model that represents spatially homogenous and isotropic accelerating universe from the perspective of the latest developments begun by Perlmutter and Riess in cosmology. For this, Friedmann–Robertson–Walker (FRW) space–time metric is considered and our universe is assumed to be filled with two types of fluids. One is ordinary baryonic perfect fluid and the other one is mysterious and bizarre dark energy perfect fluid with negative pressure. This creates a repulsive field that produces acceleration in the universe. We have used 581 Union 2.1 compilation data to statistically estimate present values of cosmological parameters Ωde, Ωm, Ωk and equation of state parameter ωde for our model. We have used 31 datasets of observed values of Hubble constant for various redshifts to estimate the present value of Hubble constant H0. On the basis of these we have calculated the present age of the universe, densities, and deceleration parameter. Evolution of deceleration parameter shows that our universe has gone through an accelerating phase two times. In the beginning, and at present. We have also calculated Particle horizon and the time at which acceleration began. Our results are close to latest surveys.