bluuebunny/crossref_metadata_2025 huggingface dataset:
Cancer Risk in Inflammatory Bowel Disease: A 6-Year Prospective Multicenter Nested Case–Control IG-IBD Study
Authors: Biancone Livia , Armuzzi Alessandro , Scribano Maria Lia , Castiglione Fabiana , D’incà Renata , Orlando Ambrogio , Papi Claudio , Daperno Marco , Vecchi Maurizio , Riegler Gabriele , Fries Walter , Alvisi Patrizia , Meucci Gianmichele , Mocciaro Filippo , Rogai Francesca , Festa Stefano , Guidi Luisa , Testa Anna , Spina Luisa , Renna Sara , Viola Anna , Patturelli Marta , Di Mitri Roberto , Frankovic Iris , Calabrese Emma , Petruzziello Carmelina , De Cristofaro Elena , Sena Giorgia , Ruffa Alessandra , Neri Benedetto , Rossi Alessandra ,   Italian Group for the Study of Inflammatory Bowel Disease (IG-IBD)
Published: July 2019

Background

In a 6-year, multicenter, prospective nested case–control study, we aimed to evaluate risk factors for incident cancer in inflammatory bowel disease (IBD), when considering clinical characteristics of IBD and immunomodulator use. The secondary end point was to provide characterization of incident cancer types.

Methods

All incident cases of cancer occurring in IBD patients from December 2011–2017 were prospectively recorded in 16 Italian Group for the Study of Inflammatory Bowel Disease units. Each of the IBD patients with a new diagnosis of cancer was matched with 2 IBD patients without cancer, according to IBD phenotype (ulcerative colitis [UC] vs Crohn’s disease [CD]), age (±5 years), sex. Risk factors were assessed by multivariate logistic regression analysis.

Results

Cancer occurred in 403 IBD patients: 204 CD (CD cases), 199 UC (UC cases). The study population included 1209 patients (403 IBD cases, 806 IBD controls). Cancer (n = 403) more frequently involved the digestive system (DS; 32%), followed by skin (14.9%), urinary tract (9.7%), lung (6.9%), genital tract (6.5%), breast (5.5%), thyroid (1.9%), lymphoma (2.7%, only in CD), adenocarcinoma of the small bowel (SBA; 3.9%, 15 CD, 1 pouch in UC), other cancers (15.9%). Among cancers of the DS, colorectal cancer (CRC) more frequently occurred in UC (29% vs 17%; P < 0.005), whereas SBA more frequently occurred in CD (13% vs 6.3% P = 0.039). In CD, perforating (B3) vs non-stricturing non-perforating (B1) behavior represented the only risk factor for any cancer (odds ratio [OR], 2.33; 95% confidence interval [CI], 1.33–4.11). In CD, risk factors for extracolonic cancer (ECC) were a B3 vs B1 and a stricturing (B2) vs B1 behavior (OR, 2.95; 95% CI, 1.62–5.43; OR, 1.79; 95% CI, 1.09–2.98). In UC, risk factors for ECC and for overall cancer were abdominal surgery for UC (OR, 4.63; 95% CI, 2.62–8.42; OR, 3.34; 95% CI, 1.88–5.92) and extensive vs distal UC (OR, 1.73; 95% CI, 1.10–2.75; OR, 1.99; 95% CI, 1.16–3.47). Another risk factor for ECC was left-sided vs distal UC (OR, 1.68; 95% CI, 1.00–2.86). Inflammatory bowel disease duration was a risk factor for skin and urinary tract cancers.

Conclusions

Perforating CD, extensive UC, and abdominal surgery for UC were identified as risk factors for overall incident cancer and for ECC. The clinical characteristics associated with severe IBD may increase cancer risk.
Global Risk and Elimination of Yellow Fever Epidemics
Authors: Ndeffo-Mbah Martial L , Pandey Abhishek
Published: July 2019

Background

Yellow fever (YF) is a vector-borne viral hemorrhagic disease endemic in Africa and Latin America. In 2016, the World Health Organization (WHO) developed the Eliminate YF Epidemics strategy aiming at eliminating YF epidemics by 2026.

Methods

We developed a spatiotemporal model of YF, accounting for the impact of temperature, vector distribution, and socioeconomic factors on disease transmission. We validated our model against previous estimates of YF basic reproductive number (R0). We used the model to estimate global risk of YF outbreaks and vaccination efforts needed to achieve elimination of YF epidemics.

Results

We showed that the global risk of YF outbreaks is highly heterogeneous. High-risk transmission areas (R0 > 6) are mainly found in West Africa and the Equatorial region of Latin America. We showed that vaccination coverage needed to eliminate YF epidemics in an endemic country varies substantially between districts. In many endemic countries, a 90% vaccination coverage is needed to achieve elimination. However, in some high-risk districts in Africa, a 95% coverage may be required.

Conclusions

Global elimination of YF epidemics requires higher population-level immunity than the 80% coverage recommended by the WHO. Optimal YF vaccination strategy should be tailored to the risk profile of each endemic country.
Use of Tissue Expansion and Serial Z-plasty for Release of Neck Postburn Scar Contracture
Authors: Song Yijun , Li Yatong , Xia Chuan , Zhang Mingzi , Yu Nanze , Huang Jiuzuo , Long Xiao , Wang Xiaojun
Published: July 2019

Z-plasty is widely employed in plastic surgery and its mainly functions include elongation along the axis of the scar, dispersal, and realigning the scar within the lines of minimal tension. It is especially useful to release linear-scar contracture, yet difficult for wide scars. Here, we described a technique of tissue expansion followed by serial Z-plasty for several cases of severe postburn scar contracture. In this procedure, first, full expansion should be achieved in the tissues adjacent to the contracture by tissue expansion. Then, the serial Z-plasty technique with precise trimming and adjustment is performed with adequate tension-free skin to release the contracture. Over a period of 2 years from 2015 to 2017, this technique was employed in moderate or severe postburn scar contracture in four patients (1 male and 3 females) aged 14 to 40 years old. The size of contracture ranged from 5 to 27 cm in diameter. Improved appearance and excellent skin match was observed in our four patients. All patients healed uneventfully without any complications and no patient required revision surgery. The range of motion, short form-36 health survey and Vancouver Scar Scale indicated that this technique offered a durable skin coverage with satisfying appearance in these patients. Through the outcomes of our patients, tissue expansion followed by serial Z-plasty has a great potential to be a useful alternative for the treatment of scar contracture especially for contracture adjacent to cervical joints.
ExoMol molecular line lists – XXXIII. The spectrum of Titanium Oxide
Authors: McKemmish Laura K , Masseron Thomas , Hoeijmakers H Jens , Pérez-Mesa Víctor , Grimm Simon L , Yurchenko Sergei N , Tennyson Jonathan
Published: July 2019

Accurate line lists are crucial for correctly modelling a variety of astrophysical phenomena, including stellar photospheres and the atmospheres of extrasolar planets. This paper presents a new line database Toto for the main isotopologues of titanium oxide (TiO): $^{46}\text{Ti}^{16}\text{O}$, $^{47}\text{Ti}^{16}\text{O}$, $^{48}\text{Ti}^{16}\text{O}$, $^{49}\text{Ti}^{16}\text{O}$, and $^{50}\text{Ti}^{16}\text{O}$. The $^{48}\text{Ti}^{16}\text{O}$ line list contains transitions with wave-numbers up to 30 000 cm−1, i.e. longwards of 0.33 μm. The Toto line list includes all dipole-allowed transitions between 13 low-lying electronic states (X 3Δ, a1Δ, d 1Σ+, E 3Π, A 3Φ, B3Π, C 3Δ, b 1Π, c1Φ, f1Δ, e 1Σ+). Ab initio potential energy curves (PECs) are computed at the icMRCI level and combined with spin–orbit and other coupling curves. These PECs and couplings are iteratively refined to match known empirical energy levels. Accurate line intensities are generated using ab initio dipole moment curves. The Toto line lists are appropriate for temperatures below 5000 K and contain 30 million transitions for $^{48}\text{Ti}^{16}\text{O}$; it is made available in electronic form via the CDS data centre and via www.exomol.com. Tests of the line lists show greatly improved agreement with observed spectra for objects such as M-dwarfs GJ876 and GL581.
Flipping-up the field: gravitational feedback as a mechanism for young clusters dispersal
Authors: Zamora-Avilés Manuel , Ballesteros-Paredes Javier , Hernández Jesús , Román-Zúñiga Carlos , Lora Verónica , Kounkel Marina
Published: July 2019

Recent analyses of Gaia data have provided direct evidence that most young stellar clusters are in a state of expansion, with velocities of the order of ∼0.5 km s−1. Traditionally, expanding young clusters have been pictured as entities that became unbound due to the lack of gravitational binding once the gas from the parental cloud that formed the cluster has been expelled by the stellar radiation of the massive stars in the cluster. In the present contribution, we used radiation-magnetohydrodynamic numerical simulations of molecular cloud formation and evolution to understand how stellar clusters form and disperse. We found that the ionizing feedback from the newborn massive stars expels the gas from the collapse centre, flipping-up the gravitational potential as a consequence of the mass removal from the inside–out. Since neither the parental clouds, nor the formed shells are distributed symmetrically around the H ii region, net forces pulling out the stars are present, accelerating them towards the edges of the cavity. We call this mechanism ‘gravitational feedback’, in which the gravity from the expelled gas appears to be the crucial mechanism producing unbound clusters that expand away from their formation centre in an accelerated way in young stellar clusters. This mechanism naturally explains the ‘Hubble flow-like’ expansion observed in several young clusters.
A rogues gallery of Andromeda’s dwarf galaxies – II. Precise distances to 17 faint satellites
Authors: Weisz Daniel R , Dolphin Andrew E , Martin Nicolas F , Albers Saundra M , Collins Michelle L M , Ferguson Annette M N , Lewis Geraint F , Mackey A Dougal , McConnachie Alan , Rich R Michael , Skillman Evan D
Published: July 2019

We present new horizontal branch (HB) distance measurements to 17 of the faintest known M31 satellites (−6 ≲ MV ≲ −13) based on deep Hubble Space Telescope (HST) imaging. The colour–magnitude diagrams extend ∼1–2 mag below the HB, which provides for well-defined HBs, even for faint galaxies in which the tip of the red giant branch (TRGB) is sparsely populated. We determine distances across the sample to an average precision of 4 per cent (∼30 kpc at 800 kpc). We find that the majority of these galaxies are in good agreement, though slightly farther (0.1–0.2 mag) when compared to recent ground-based TRGB distances. Two galaxies (And IX and And XVII) have discrepant HST and ground-based distances by ∼0.3 mag (∼150 kpc), which may be due to contamination from Milky Way foreground stars and/or M31 halo stars in sparsely populated TRGB regions. We use the new distances to update the luminosities and structural parameters for these 17 M31 satellites. The new distances do not substantially change the spatial configuration of the M31 satellite system. We comment on future prospects for precise and accurate HB distances for faint galaxies in the Local Group and beyond.
Failure of Flow Diverter Therapy: Predictors and Management Strategies
Authors: Bonney Phillip A , Connor Michelle , Fujii Tatsuhiro , Singh Parampreet , Koch Matthew J , Stapleton Christopher J , Mack William J , Walcott Brian P
Published: July 2019

Flow diversion is a safe and effective treatment for many types of brain aneurysms. Even so, there remain some aneurysms that persist despite initial treatment. In studies with the longest follow-up (5 yr), at least 5% of aneurysms persist with this treatment modality. As the cumulative experience and clinical indications for flow diversion continue to expand, the anatomic and functional characteristics that are associated with aneurysm persistence are increasingly described. Identification of these factors preoperatively can help to guide initial treatment decisions, enhance monitoring protocols in the follow-up period, and establish best practices for re-treatment when necessary. Herein, we review published clinical series and provide examples to highlight variables implicated in aneurysm persistence after treatment with flow diversion.
Detection and Quantification of Spongospora subterranea Sporosori in Soil by Quantitative Real-Time PCR
Authors: Mallik Ipsita , Fulladolsa Ana Cristina , Yellareddygari S. K. R. , Bittara Francisco G. , Charkowski Amy O. , Gudmestad Neil C.
Published: July 2019

Powdery scab on potato tubers is caused by the obligate soilborne biotroph Spongospora subterranea and is known to cause substantial losses in potato production. The pathogen also infects roots of susceptible hosts, forming galls which can negatively affect root function. S. subterranea is also the vector of Potato mop-top virus, which causes a tuber necrosis disease that can, depending on temperature and cultivar, render potato tubers unmarketable. In this study, we adapted a published protocol to develop a sensitive and robust quantitative real-time PCR (qPCR) assay using specific primers and probes for detecting and quantifying S. subterranea sporosori in soil types that differ in physical properties, including organic matter content and soil pH. For the first time, an external control was utilized and applied directly to the soil prior to DNA extraction, which facilitated normalization of S. subterranea sporosori soil levels from sample to sample. The duplex qPCR protocol was demonstrated to be highly sensitive, capable of detecting and quantifying as few as 1 sporosorus/g of soil, with consistently high qPCR efficiency and the coefficient of determination (R2) values ranging from 94 to 99% and 0.98 to 0.99, respectively. The protocol was successfully implemented in enumerating S. subterranea sporosori in naturally infested field soil collected from several states and in artificial potting mixes with high organic matter content ranging from 64 to 71%. The qPCR method developed can be useful for potato growers to avoid agricultural soils highly infested with S. subterranea and in the development of risk assessment models in the future that incorporate cultivar susceptibility to powdery scab and soil infestation levels.
Transcriptional Profiling of Diffusible Lipopeptides and Fungal Virulence Genes During Bacillus amyloliquefaciens EZ1509-Mediated Suppression of Sclerotinia sclerotiorum
Authors: Farzand Ayaz , Moosa Anam , Zubair Muhammad , Khan Abdur Rashid , Ayaz Muhammad , Massawe Venance Colman , Gao Xuewen
Published: July 2019

Sclerotinia sclerotiorum is a devastating necrotrophic pathogen that infects multiple crops, and its control is an unremitting challenge. In this work, we attempted to gain insights into the pivotal role of lipopeptides (LPs) in the antifungal activity of Bacillus amyloliquefaciens EZ1509. In a comparative study involving five Bacillus strains, B. amyloliquefaciens EZ1509 harboring four LPs biosynthetic genes (viz. surfactin, iturin, fengycin, and bacilysin) exhibited promising antifungal activity against S. sclerotiorum in a dual-culture assay. Our data demonstrated a remarkable upsurge in LPs biosynthetic gene expression through quantitative reverse transcription PCR during in vitro interaction assay with S. sclerotiorum. Maximum upregulation in LPs biosynthetic genes was observed on the second and third days of in vitro interaction, with iturin and fengycin being the highly expressed genes. Subsequently, Matrix-assisted laser desorption/ionization-time of flight-mass spectrometry analysis confirmed the presence of LPs in the inhibition zone. Scanning electron microscope analysis showed disintegration, shrinkage, plasmolysis, and breakdown of fungal hyphae. During in planta evaluation, S. sclerotiorum previously challenged with EZ1509 showed significant suppression in pathogenicity on detached leaves of tobacco and rapeseed. The oxalic acid synthesis was also significantly reduced in S. sclerotiorum previously confronted with antagonistic bacterium. The expression of major virulence genes of S. sclerotiorum, including endopolygalacturonase-3, oxalic acid hydrolase, and endopolygalacturonase-6, was significantly downregulated during in vitro confrontation with EZ1509.
Rapid Bayesian learning in the mammalian olfactory system
Authors: Hiratani Naoki , Latham Peter E.
Published: July 2019

Many experimental studies suggest that animals can rapidly learn to identify odors and predict the rewards associated with them. However, the underlying plasticity mechanism remains elusive. In particular, it is not clear how olfactory circuits achieve rapid, data efficient learning with local synaptic plasticity. Here, we formulate olfactory learning as a Bayesian optimization process, then map the learning rules into a computational model of the mammalian olfactory circuit. The model is capable of odor identification from a small number of observations, while reproducing cellular plasticity commonly observed during development. We extend the framework to reward-based learning, and show that the circuit is able to rapidly learn odor-reward association with a plausible neural architecture. These results deepen our theoretical understanding of unsupervised learning in the mammalian brain.
Goodness-of-fit filtering in classical metric multidimensional scaling with large datasets
Authors: Graffelman Jan
Published: July 2019

Metric multidimensional scaling (MDS) is a widely used multivariate method with applications in almost all scientific disciplines. Eigenvalues obtained in the analysis are usually reported in order to calculate the over-all goodness-of-fit of the distance matrix. In this paper, we refine MDS goodness-of-fit calculations, proposing additional point and pairwise good-ness-of-fit statistics that can be used to filter poorly represented observations in MDS maps. The proposed statistics are especially relevant for large data sets that contain outliers, with typically many poorly fitted observations, and are helpful for improving MDS output and emphasising the most important features of the dataset. Several goodness-of-fit statistics are considered, and both Euclidean and non-Euclidean distance matrices are considered. Some examples with data from demographic, genetic and geographic studies are shown.
Temporal preparation and short-term temporal memory in depression
Authors: Hsu Tzu-Yu , Lee Hsin-Chien , Lane Timothy Joseph , Missal Marcus
Published: July 2019

Patient suffering of Major Depressive Disorder (MDD) often complain that subjective time seems to ‘drag’ with respect to physical time. This may point towards a generalized dysfunction of temporal processing in MDD. In the present study, we investigated temporal preparation in MDD. “Temporal preparation” refers to an increased readiness to act before an expected event; consequently, reaction time should be reduced. MDD patients and age-matched controls were required to make a saccadic eye movement between a central and an eccentric visual target after a variable duration preparatory period. We found that MDD patients produced a larger number of premature saccades, saccades initiated prior to the appearance of the expected stimulus. These saccades were not temporally controlled; instead, they seemed to reflect increased oculomotor impulsivity. In contrast, the latency of visually-guided saccades was strongly influenced by temporal preparation in controls; significantly less so, in MDD patients. This observed reduced temporal preparation in MDD was associated with a faster decay of short-term temporal memory. Moreover, in patients producing a lot of premature responses, temporal preparation to early imperative stimuli was increased. A reduction in premature saccades, however, was associated with reduced temporal preparation to late imperative stimuli.

In conclusion, reduced temporal preparation and short-term temporal memory in the oculomotor domain supports the hypothesis that temporal processing was altered in MDD patients. These observed deficits could reflect other underlying aspects of abnormal time experience in MDD.
Cryptic prophage-encoded small protein DicB protectsEscherichia colifrom phage infection by inhibiting inner membrane receptor proteins
Authors: Ragunathan Preethi T. , Vanderpool Carin K.
Published: July 2019

Bacterial genomes harbor cryptic prophages that have lost genes required for induction, excision from host chromosomes, or production of phage progeny.Escherichia coliK12 strains contain a cryptic prophage Qin that encodes a small RNA, DicF, and small protein, DicB, that have been implicated in control of bacterial metabolism and cell division. Since DicB and DicF are encoded in the Qin immunity region, we tested whether these gene products could protect theE. colihost from bacteriophage infection. Transient expression of thedicBFoperon yielded cells that were ~100-fold more resistant to infection by λ phage than control cells, and the phenotype was DicB-dependent. DicB specifically inhibited infection by λ and other phages that use ManYZ membrane proteins for cytoplasmic entry of phage DNA. In addition to blocking ManYZ-dependent phage infection, DicB also inhibited the canonical sugar transport activity of ManYZ. Previous studies demonstrated that DicB interacts with MinC, an FtsZ polymerization inhibitor, causing MinC localization to mid-cell and preventing Z ring formation and cell division. In strains producing mutant MinC proteins that do not interact with DicB, both DicB-dependent phenotypes involving ManYZ were lost. These results suggest that DicB is a pleiotropic regulator of bacterial physiology and cell division, and that these effects are mediated by a key molecular interaction with the cell division protein MinC.

Importance

Temperate bacteriophages can integrate their genomes into the bacterial host chromosome and exist as prophages whose gene products play key roles in bacterial fitness and interactions with eukaryotic host organisms. Most bacterial chromosomes contain “cryptic” prophages that have lost genes required for production of phage progeny but retain genes of unknown function that may be important for regulating bacterial host physiology. This study provides such an example – where a cryptic prophage-encoded product can perform multiple roles in the bacterial host and influence processes including metabolism, cell division, and susceptibility to phage infection. Further functional characterization of cryptic prophage-encoded functions will shed new light on host-phage interactions and their cellular physiological implications.
An improved sexual genetic algorithm for solving 0/1 multidimensional knapsack problem
Authors: Laabadi Soukaina , Naimi Mohamed , El Amri Hassan , Achchab Boujemâa
Published: July 2019

Purpose

The purpose of this paper is to provide an improved genetic algorithm to solve 0/1 multidimensional knapsack problem (0/1 MKP), by proposing new selection and crossover operators that cooperate to explore the search space.

Design/methodology/approach

The authors first present a new sexual selection strategy that significantly improves the one proposed by (Varnamkhasti and Lee, 2012), while working in phenotype space. Then they propose two variants of the two-stage recombination operator of (Aghezzaf and Naimi, 2009), while they adapt the latter in the context of 0/1 MKP. The authors evaluate the efficiency of both proposed operators on a large set of 0/1 MKP benchmark instances. The obtained results are compared against that of conventional selection and crossover operators, in terms of solution quality and computing time.

Findings

The paper shows that the proposed selection respects the two major factors of any metaheuristic: exploration and exploitation aspects. Furthermore, the first variant of the two-stage recombination operator pushes the search space towards exploitation, while the second variant increases the genetic diversity. The paper then demonstrates that the improved genetic algorithm combining the two proposed operators is a competitive method for solving the 0/1 MKP.

Practical implications

Although only 0/1 MKP standard instances were tested in the empirical experiments in this paper, the improved genetic algorithm can be used as a powerful tool to solve many real-world applications of 0/1 MKP, as the latter models several industrial and investment issues. Moreover, the proposed selection and crossover operators can be incorporated into other bio-inspired algorithms to improve their performance. Furthermore, the two proposed operators can be adapted to solve other binary combinatorial optimization problems.

Originality/value

This research study provides an effective solution for a well-known non-deterministic polynomial-time (NP)-hard combinatorial optimization problem; that is 0/1 MKP, by tackling it with an improved genetic algorithm. The proposed evolutionary mechanism is based on two new genetic operators. The first proposed operator is a new and deeply different variant of the so-called sexual selection that has been rarely addressed in the literature. The second proposed operator is an adaptation of the two-stage recombination operator in the 0/1 MKP context. This adaptation results in two variants of the two-stage recombination operator that aim to improve the quality of encountered solutions, while taking advantage of the sexual selection criteria to prevent the classical issue of genetic algorithm that is premature convergence.
Vehicles distance estimation using detection of vanishing point
Authors: Bougharriou Sana , Hamdaoui Fayçal , Mtibaa Abdellatif
Published: July 2019

Purpose

This paper aims to study distance determination in vehicles, which could allow an in-car system to provide feedback and alert drivers, by either prompting the driver to take preventative action or prepare the vehicle’s safety systems for an imminent collision. The success of a new system's deploying allows drivers to oppose the huge number of accidents and the material losses and costs associated with car accidents.

Design/methodology/approach

In this context, this paper presents estimation distance between camera and frontal vehicles based on camera calibration by combining three main steps: vanishing point extraction, lanes detection and vehicles detection in the field of 3 D real scene. This algorithm was implemented in MATLAB, and it was applied on scenes containing several vehicles in highway urban area. The method starts with the camera calibration. Then, the distance information can be calculated.

Findings

Based on experiment performance, this new method achieves robustness especially for detecting and estimating distances for multiple vehicles in a single scene. Also, this method demonstrates a higher accuracy detection rate of 0.869 in an execution time of 2.382 ms.

Originality/value

The novelty of the proposed method consists firstly on the use of an adaptive segmentation to reject the false points of interests. Secondly, the use of vanishing point has reduced the cost of using memory. Indeed, the part of the image above the vanishing point will not be processed and therefore will be deleted. The last benefit is the application of this new method on structured roads.
A relaxed structural mechanics and fuzzy control for fluid–structure dynamic analysis
Authors: Chen Tim , Khurram Safiullahand , Cheng CYJ
Published: July 2019

Purpose

This paper aims to deal with the problem of the global stabilization for a class of tension leg platform (TLP) nonlinear control systems.

Design/methodology/approach

It is well-known that, in general, the global asymptotic stability of the TLP subsystems does not imply the global asymptotic stability of the composite closed-loop system.

Findings

An effective approach is proposed to control chaos via the combination of fuzzy controllers, fuzzy observers and dithers.

Research limitations/implications

If a fuzzy controller and a fuzzy observer cannot stabilize the chaotic system, a dither, as an auxiliary of the controller and the observer, is simultaneously introduced to asymptotically stabilize the chaotic system.

Originality/value

Thus, the behavior of the closed-loop dithered chaotic system can be rigorously predicted by establishing that of the closed-loop fuzzy relaxed system.
Strategic merge: a gain or a gamble – the case of Telco China
Authors: Li Wing Sun
Published: July 2019

Learning outcomes

By reviewing the case study, readers are expected to understand the constraints of competitive strategies in a shifting environmental landscape; the difficulties of foreign companies to sustain in an emerging market with government interventions; the subtlety of joint venture (JV) formation by partners with very divergent background, priority and agenda; evaluation of behavioural orientations of partnership and JV operational arrangements as determinants of a successful JV strategy.

Case overview/synopsis

High-tech companies can enjoy super profits from their products when only a few competitors can compete with them technologically. However, these companies also nurture a high-cost operational culture that sets a constraint for their further growth when superiority of the technology can no longer be maintained. High-tech companies may reposition their businesses with a strategic shift from differentiation strategy to cost focus strategy. The attendant shift as well as synchronization problem in an organization may require a larger effort to revamp. This case describes a global telecom infrastructure company with successful business performance in China in her early establishment with a pre-emptive technological edge. Mitigation of technological superiority and the rise of local competitors have forced the Company to opt for a cooperative strategy with a local player in the establishment of a low-cost joint venture. Does the new joint venture facilitate the strategic shift or just create an illusion of cooperation?

Complexity academic level

Undergraduate students and post graduate students taking strategic management course.

Supplementary materials

Teaching Notes are available for educators only. Please contact your library to gain login details or emailsupport@emeraldinsight.comto request teaching notes.

Subject code

CSS 11: Strategy.
Polic(y)ing time and curriculum: how teachers critically negotiate restrictive policies
Authors: Wessel-Powell Christy , Buchholz Beth Anne , Brownell Cassie J.
Published: July 2019

Purpose

The purpose of this paper is to theorize teacher agency as enacted through a P/policymaking lens in three elementary classrooms. Big-P Policies are formal, top-down school reform policies legislated, created, implemented and regulated by national, state and local governments. Yet, Big-P policies are not the only policies enacted in literacies classrooms. Rather, little-p policies or teachers’ local, personal and creative enactments of their values and expertise are also in play in daily classroom decisions. Little p-policies are teachers doing their best in response to their students and school contexts.

Design/methodology/approach

Adapting elements of discursive analysis, this interpretive inquiry is designed to examine textual artifacts, situated alongside classroom events and particular local practices, to explicate what teachers’ policymaking enactments regarding time and curriculum look like across three distinct contexts. Using three elementary classrooms as examples, this paper provides analytic snapshots illustrating teachers’ policymaking to solve problems of practice posed by state and school policies for curriculum, and for use of time at school.

Findings

The findings suggest that teachers ration (aliz)ed use of time in ways that enacted personal politics, to prioritize children’s personal growth and well-being alongside teachers’ values, even when use of time became “inefficient.” An artifact from three focal classrooms illustrates particular practices – scheduling, connecting and modeling – teachers leveraged to enact little p-policy. Teachers’ little p-policy enactment is teacher agency, used to disrupt temporal and curricular policies.

Originality/value

This framing is valuable because little-p policymaking works to disrupt and negotiate temporal and curricular mandates imposed on classrooms from the outside.
Direct numerical simulations of laminar and transitional flows in diverging pipes
Authors: Vittal Shenoy Dhanush , Safdari Shadloo Mostafa , Peixinho Jorge , Hadjadj Abdellah
Published: July 2019

Purpose

Fluid flows in pipes whose cross-sectional area are increasing in the stream-wise direction are prone to separation of the recirculation region. This paper aims to investigate such fluid flow in expansion pipe systems using direct numerical simulations. The flow in circular diverging pipes with different diverging half angles, namely, 45, 26, 14, 7.2 and 4.7 degrees, are considered. The flow is fed by a fully developed laminar parabolic velocity profile at its inlet and is connected to a long straight circular pipe at its downstream to characterise recirculation zone and skin friction coefficient in the laminar regime. The flow is considered linearly stable for Reynolds numbers sufficiently below natural transition. A perturbation is added to the inlet fully developed laminar velocity profile to test the flow response to finite amplitude disturbances and to characterise sub-critical transition.

Design/methodology/approach

Direct numerical simulations of the Navier–Stokes equations have been solved using a spectral element method.

Findings

It is found that the onset of disordered motion and the dynamics of the localised turbulence patch are controlled by the Reynolds number, the perturbation amplitude and the half angle of the pipe.

Originality/value

The authors clarify different stages of flow behaviour under the finite amplitude perturbations and shed more light to flow physics such as existence of Kelvin–Helmholtz instabilities as well as mechanism of turbulent puff shedding in diverging pipe flows.
Free convection heat transfer of MgO-MWCNTs/EG hybrid nanofluid in a porous complex shaped cavity with MHD and thermal radiation effects
Authors: Ghalambaz Mohammad , Sabour Mahmoud , Pop Ioan , Wen Dongsheng
Published: July 2019

Purpose

The present study aims to address the flow and heat transfer of MgO-MWCNTs/EG hybrid nanofluid in a complex shape enclosure filled with a porous medium. The enclosure is subject to a uniform inclined magnetic field and radiation effects. The effect of the presence of a variable magnetic field on the natural convection heat transfer of hybrid nanofluids in a complex shape cavity is studied for the first time. The geometry of the cavity is an annular space with an isothermal wavy outer cold wall. Two types of the porous medium, glass ball and aluminum metal foam, are adopted for the porous space. The governing equations for mass, momentum and heat transfer of the hybrid nanofluid are introduced and transformed into non-dimensional form. The actual available thermal conductivity and dynamic viscosity data for the hybrid nanofluid are directly used for thermophysical properties of the hybrid nanofluid.

Design/methodology/approach

The governing equations for mass, momentum and heat transfer of hybrid nanofluid are introduced and transformed into non-dimensional form. The thermal conductivity and dynamic viscosity of the nanofluid are directly used from the experimental results available in the literature. The finite element method is used to solve the governing equations. Grid check procedure and validations were performed.

Findings

The effect of Hartmann number, Rayleigh number, Darcy number, the shape of the cavity and the type of porous medium on the thermal performance of the cavity are studied. The outcomes show that using the composite nanoparticles boosts the convective heat transfer. However, the rise of the volume fraction of nanoparticles would reduce the overall enhancement. Considering a convective dominant regime of natural convection flow with Rayleigh number of 107, the maximum enhancement ratio (Nusselt number ratio compared to the pure fluid) for the case of glass ball is about 1.17 and for the case of aluminum metal foam is about 1.15 when the volume fraction of hybrid nanoparticles is minimum as 0.2 per cent.

Originality/value

The effect of the presence of a variable magnetic field on the natural convection heat transfer of a new type of hybrid nanofluids, MgO-MWCNTs/EG, in a complex shape cavity is studied for the first time. The results of this paper are new and original with many practical applications of hybrid nanofluids in the modern industry.
Transient numerical investigation of a large-scale hydro-pneumatic suspension considering variations in check valve parameters and operational conditions
Authors: Zhang Sha , Gu Zhengqi , Wu Wenguang , Zheng Ledian , Liu Jun , Yin Shanbin
Published: July 2019

Purpose

The purpose of this paper is to develop a numerical model used for calculating the nonlinearities of large-scale hydro-pneumatic suspension (HPS) and investigating the effects of variations in flow path and operational parameter on suspension damping response.

Design/methodology/approach

To parameterization nonlinearities of the suspension, the author developed a two-phase flow model of a large-scale HPS based on computational fluid dynamics and volume of fluid method. Considerable effort was made to verify the nonlinearities by field measurements carried out on an off-highway mining dump truck. The investigation of effects of variations in flow path and operational parameter on damping characteristics highlights the necessity of the numerical simulation.

Findings

The two-phase flow model can represent the gas-oil interaction and simulate the suspension operational movement conveniently. Transient numerical simulation results can be used to model the nonlinearities of large-scale HPS accurately. A new phenomenon was discovered that the pressure in rebound chamber presents reduction trend during compression stroke in special cases. It has never been reported before.

Originality/value

Developed a two-phase flow model of a large-scale HPS, which can manage the gas-oil interaction and capture the complex flow field structure in it. The paper is the first study to model the nonlinearities of a large-scale HPS used in off-highway mining dump truck through transient numerical simulation. Compared with previous researches, such a research not only gives new insight and thorough understanding into the suspension internal fluid structure but also can give good guiding opinions to the optimal design of HPS.
Investigations on tribological behaviour of AA7075-TiO2 composites under dry sliding conditions
Authors: S.V. Alagarsamy , M. Ravichandran
Published: July 2019

Purpose

Aluminium and its alloys are the most preferred material in aerospace and automotive industries because of their high strength-to-weight ratio. However, these alloys are found to be low wear resistance. Hence, the incorporation of ceramic particles with the aluminium alloy may be enhanced the mechanical and tribological properties. The purpose of this study is to optimize the specific wear rate and friction coefficient of titanium dioxide (TiO2) reinforced AA7075 matrix composites. The four wear control factors are considered, i.e. reinforcement (Wt.%), applied load (N), sliding velocity (m/s) and sliding distance (m).

Design/methodology/approach

The composites were fabricated through stir casting route with varying weight percentages (0, 5, 10 and 15 Wt.%) of TiO2 particulates. The mechanical properties of the composites were studied. The specific wear rate and friction coefficient of the newly prepared composites was determined by using a pin-on-disc apparatus under dry sliding conditions. Experiments were planned as per Taguchi’s L16 orthogonal design. Signal-to-noise ratio analysis was used to find the optimal combination of parameters.

Findings

The mechanical properties such as yield strength, tensile strength and hardness of the composites significantly improved with the addition of TiO2 particles. The analysis of variance result shows that the applied load and reinforcement Wt.% are the most influencing parameters on specific wear rate and friction coefficient during dry sliding conditions. The scanning electron microscope morphology of the worn surface shows that TiO2 particles protect the matrix from more removal of material at all conditions.

Originality/value

This paper provides a solution for optimal parameters on specific wear rate and friction coefficient of aluminium matrix composites (AMCs) using Taguchi methodology. The obtained results are useful in improving the wear resistance of the AA7075-TiO2 composites.
Analysis and simulation of straight-through labyrinth seal in hydrostatic support system
Authors: Zhang Xiumin , Yin Mingfu , Sun Huilai
Published: July 2019

Purpose

The purpose of this paper is to improve the bearing capacity and mechanical properties of the oil pocket.

Design/methodology/approach

In this paper, a straight-through labyrinth seal is installed in an oil sealing belt. The main structure of hydrostatic support system (HSS) is introduced, and the factors affecting the leakage loss are analyzed. The governing equations involving the momentum equation and the continuity equation for the land section and groove section are established separately based on the three-control-volume theory. To explain the flow capability of the straight-through labyrinth seal, the labyrinth seal with different clearance widths, groove numbers, groove depths and pressure difference is calculated. The results of the simulation are compared and analyzed.

Findings

The groove dimensions and groove numbers have important impact on the leakage and flow pattern of the seal.

Research limitations/implications

The fluid flow was simulated by commercial tools executed in the ANSYS Fluent, the computational fluid dynamics (CFD) solver and a steady state scheme with the realizable k-ε turbulence model was applied. The cavity structure of the straight-through labyrinth seal, forming turbulence eddy flows in the groove, which is a valid approach to convert turbulence kinetic energy into thermal energy, reduce leakage mass flow.

Practical implications

This research can provide the theoretical basis and technical support which is conducive to the practical application of the straight-through labyrinth seal in HSS.

Social implications

A new design structure is proposed to improve the bearing capacity and economic benefit of HSSs.

Originality/value

A straight-through labyrinth seal is applied to the oil sealing belt and the three-control-volume governing equation is established.
In situ Raman spectroscopy study on the effect of antioxidants on high temperature oxidation properties of TMPTO
Authors: Cheng Bingxue , Duan Haitao , Jin Yongliang , Wei Lei , Dan Jia , Chen Song , Li Jian
Published: July 2019

Purpose

This paper aims to investigate the thermal oxidation characteristics of the unsaturated bonds (C=C) of trimethylolpropane trioleate (TMPTO) and to reveal the high temperature oxidation decay mechanism of unsaturated esters and the nature of the anti-oxidation properties of the additives.

Design/methodology/approach

Using a DXR laser microscopic Raman spectrometer and Linkam FTIR600 temperature control platform, the isothermal oxidation experiments of TMPTO with or without 1.0 wt. % of different antioxidants were performed.

Findings

The results indicated that the Raman peaks of =C-H, C=C and -CH2- weaken gradually with prolonged oxidation time, and the corresponding Raman intensities drop rapidly at higher temperatures. The aromatic amine antioxidant can decrease the attenuation of peak intensity, as it significantly reduces the rate constant of C=C thermal oxidation. The hindered phenolic antioxidant has a protective effect during the early stages of oxidation (induction period), but it may accelerate the oxidation of C=C afterwards.

Originality/value

Research on the structure changes of synthetic esters during oxidation by Raman spectroscopy will be of great importance in promoting the use of Raman spectroscopy to analyze the oxidation of lubricants.
A practical process mining approach for compliance management
Authors: Becker Michael , Buchkremer Rüdiger
Published: July 2019

Purpose

The purpose of this study is to examine whether the compliance management activities in the risk management environment of financial institutions can be enhanced using a Process Mining application.

Design/methodology/approach

In this research, an implementation procedure for a selected Process Mining application is developed and evaluated at a financial institution in Germany.

Findings

The evaluation of the process data with the Process Mining application Disco shows that the compliance of the real-life execution of business processes can be monitored in real-time. Moreover, potential non-compliant activities and durations can be analysed in a detailed manner.

Research limitations/implications

When the research results are regarded, it must be considered that a general condition for the usage of a Process Mining application is that the process data is available and exportable in the required format and that data privacy regulations are fulfilled.

Originality/value

This research presents a practical use case for the implementation of a Process Mining application at the risk management department of financial institutions. It shows the value of using a technical application to carry out tedious tasks that are usually executed manually. This value is discussed and compared with the aim to help financial institutions in determining how the effectiveness and efficiencies of compliance management activities can be improved. Therefore, this research can be taken as a foundation for the practical implementation of a Process Mining application at financial institutions.
Incorporating resilience determinants in supply chain network design model
Authors: Mikhail Mina , El-Beheiry Mohammed , Afia Nahid
Published: July 2019

Purpose

The purpose of this paper is to develop a decision tool that enables supply chain (SC) architects to design resilient SC networks (SCNs). Two resilience design determinants are considered: SC density and node criticality. The effect of considering these determinants on network structures is highlighted based on the ability to resist disruptions and how SC performance is affected.

Design/methodology/approach

A mixed-integer non-linear programming model is proposed as a proactive strategy to develop resilient structures; design determinants are formulated and considered as constraints. An upper limit is set for each determinant, and resistance capacity and performance of the developed structures are evaluated. These upper limits are then changed until SC performance stabilizes in case of no disruption.

Findings

Resilient SCN structures are achieved at relatively low design determinants levels on the expense of profit and without experiencing shortage in case of no disruption. This reduction in profit can be minimized on setting counter values for the two determinants; relatively higher SC density with lower node criticality or vice versa. At very low SC density levels, the design model will reduce the number of open facilities largely leading to only one facility open at each echelon; therefore, shortage occurs and vulnerability to disruption increases. On the other hand, at high determinants levels, SC vulnerability also increases as a result of having more geographically clustered structures with higher inbound and outbound flows for each facility.

Originality/value

In this paper, a novel proactive decision tool is adopted to design resilient SCNs. Previous literature used metrics for SC density and node criticality to assess resilience; in this research, determinants are incorporated directly as constraints in the design model. Results give insight to SC architects on how to set determinant values to reach resilient structures with minimum performance loss in case of no disruption.