A technique to prove parameter-uniform convergence for a singularly perturbed convection–diffusion equation

AbstractA priori parameter explicit bounds on the solution of singularly perturbed elliptic problems of convection–diffusion type are established. Regular exponential boundary layers can appear in the solution. These bounds on the solutions and its derivatives are obtained using a suitable decomposition of the solution into regular and layer components. By introducing extensions of the coefficients to a larger domain, artificial compatibility conditions are not imposed in the derivation of these decompositions

Numerical approximations to a singularly perturbed convection-diffusion problem with a discontinuous initial condition

A singularly perturbed parabolic problem of convection-diffusion type with a discontinuous initial condition is examined. An analytic function is identified which matches the discontinuity in the initial condition and also satisfies the homogenous parabolic differential equation associated with the problem. The difference between this analytical function and the solution of the parabolic problem is approximated numerically, using an upwind finite difference operator combined with an appropriate layer-adapted mesh. The numerical method is shown to be parameter-uniform. Numerical results are presented to illustrate the theoretical error bounds established in the paper. © 2021, The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature

Convergent evolution of pregnancy-specific glycoproteins in human and horse

Pregnancy-specific glycoproteins (PSGs) are members of the carcinoembryonic antigen cell adhesion molecule (CEACAM) family that are secreted by trophoblast cells. PSGs may modulate immune, angiogenic and platelet responses during pregnancy. Until now, PSGs are only found in species that have a highly invasive (hemochorial) placentation including humans, mice and rats. Surprisingly, analyzing the CEACAM gene family of the horse, which has a non-invasive epitheliochorial placenta, with the exception of the transient endometrial cups, we identified equine CEACAM family members that seem to be related to PSGs of rodents and primates. We identified seven genes that encode secreted PSG-like CEACAMs. Phylogenetic analyses indicate that they evolved independently from an equine CEACAM1-like ancestor rather than from a common PSG-like ancestor with rodents and primates. Significantly, expression of PSG-like genes (CEACAM44, CEACAM48, CEACAM49 and CEACAM55) was found in non-invasive as well as invasive trophoblast cells such as purified chorionic girdle cells and endometrial cup cells. Chorionic girdle cells are highly invasive trophoblast cells that invade the endometrium of the mare where they form endometrial cups and are in close contact with maternal immune cells. Therefore, the microenvironment of invasive equine trophoblast cells has striking similarities to the microenvironment of trophoblast cells in hemochorial placentas, suggesting that equine PSG-like CEACAMs and rodent and primate PSGs have undergone convergent evolution. This is supported by our finding that equine PSG-like CEACAM49 exhibits similar activity to certain rodent and human PSGs in a functional assay of platelet–fibrinogen binding. Our results have implications for understanding the evolution of PSGs and their functions in maternal–fetal interactions

Assessing the combined effect of surface topography and substrate rigidity in human bone marrow stem cell cultures

The combined effect of surface topography and substrate rigidity in stem cell cultures is still under-investigated, especially when biodegradable polymers are used. Herein, we assessed human bone marrow stem cell response on aliphatic polyester substrates as a function of anisotropic grooved topography and rigidity (7 and 12 kPa). Planar tissue culture plastic (TCP, 3 GPa) and aliphatic polyester substrates were used as controls. Cell morphology analysis revealed that grooved substrates caused nuclei orientation/alignment in the direction of the grooves. After 21 days in osteogenic and chondrogenic media, the 3 GPa TCP and the grooved 12 kPa substrate induced significantly higher calcium deposition and alkaline phosphatase (ALP) activity and glycosaminoglycan (GAG) deposition, respectively, than the other groups. After 14 days in tenogenic media, the 3 GPa TCP upregulated four and downregulated four genes; the planar 7 kPa substrate upregulated seven genes and downregulated one gene; and the grooved 12 kPa substrate upregulated seven genes and downregulated one gene. After 21 days in adipogenic media, the softest (7 kPa) substrates induced significantly higher oil droplet deposition than the other substrates and the grooved substrate induced significantly higher droplet deposition than the planar. Our data pave the way for more rational design of bioinspired constructs.This work has also received funding from the European Union’s Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie, grant agreement No. 676338, the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation programme, grant agreement No. 866126 and the European Union’s Horizon 2020 research and innova tion Widespread: Twinning programme, grant agreement No. 810850. This publication has emanated from research supported in part by grants from Science Foundation Ireland (SFI) under Grant numbers 15/CDA/3629 and 19/FFP/6982 and Science Foundation Ireland (SFI) and European Regional Development Fund (ERDF) under grant number 13/RC/2073_2. E.M.F. acknowledges to the project TERM RES Hub – Infraestrutura Científica para a Engenharia de Tecidos e Medicina Regenerativa, Ref Num ber NORTE-01-0145-FEDER-02219015. The authors would like to acknowledge the significant contribution of Dr Oonagh Dwane in the writing and management of all grants. Open access funding provided by IReL

Antimicrobial drug usage from birth to 180 days of age in Irish dairy calves and in suckler beef calves

peer-reviewedConcern about the use of antimicrobials in food producing animals is increasing. The study objective was to quantify antimicrobial drug usage in calves using antimicrobial treatment records from Irish suckler beef and dairy farms. Antimicrobial treatment records for calves born between 1 July 2014 and 30 June 2015 on 79 suckler beef and 44 dairy farms were analyzed. Calves were followed from birth (day 0) until 6 months of age. According to standard farm protocol, calves exhibiting clinical signs of any disease were identified and antimicrobial treatment was administered. Farmers recorded the following information for each treatment administered: calf identification, age at treatment, disease event, drug name, number of treatment days, and amount of drug administered. In total, 3,204 suckler beef calves and 5,358 dairy calves, representing 540,953 and 579,997 calf-days at risk, respectively, were included in the study. A total of 1,770 antimicrobial treatments were administered to suckler beef (n = 841) and dairy calves (n = 929) between birth and 6 months of age. There was large variation in TIDDDvet and TIDCDvet by farm. This study provides new insights into the time periods and indications for which specific antimicrobial substances are used in Irish dairy and beef suckler calves

Electrochemical sensors for worker safety in manufacturing industries

The National Institute for Occupational Safety and Health has attributed most occupational diseases of industrial workers to excessive exposure to dangerous substances. In particular, occupational lung diseases are caused by the inhalation of harmful substances such as dust particles and gases [1]. The use of DPI and periodic health checks for industrial workers certainly reduces risks, but a more effective prevention strategy should include real-time monitoring of physiological parameters [2]. In this context, recent academic and industrial research has focused on the development of smart wearable systems for continuous health monitoring. This has been possible mainly due to significant progress in micro- and nanotechnology and the miniaturization of devices [3]. In such regard, electrochemical sensors represent a promising alternative due to their speed of response, simplicity of operation, and lower cost than traditional methods of diagnosis [4]. This research activity involves the development of a smart mask based on an electrochemical sensor for the non-invasive detection of hydrogen peroxide in exhaled breath. In particular, a higher concentration of this biomarker indicates the onset of oxidative stress, a pathological condition that can lead to more serious diseases, such as asthma and COPD (Chronic Obstructive Pulmonary Disease) [5]. This sensor was fabricated through a sustainable production process, from the CDs at the end of life because their silver layer can be used for its good electrochemical properties. In particular, this layer was peeled off the CD and a three electrodes configuration was given using a laser cutter

Building productive relationships with young people with SEBD in transition: the role of identity

This article reports a study of the experiences of school leavers with social, emotional and behavioural difficulties (SEBD), which identified supportive relationships as key elements in young people demonstrating resilience through this transitional period. Almost all the young people involved in the study had access to potential helpers, but few managed to establish productive relationships with them. Analysis of interviews, conducted over a 15 month period with a group of 15 school leavers, their parents and those who worked with them, suggested that barriers and facilitators to relationship development existed at two levels: institutional and individual. This article focuses on the individual level, in which identity processes appear to play a key role. These processes are used to explain why some school leavers built productive relationships and thrived, whilst many failed to do so, and struggled. These findings have implications for policy, practice and theory

Empathy at Play:Embodying Posthuman Subjectivities in Gaming

In this article, we address the need for a posthuman account of the relationship between the avatar and player. We draw on a particular line of posthumanist theory associated closely with the work of Karen Barad, Rosi Braidotti and N. Katherine Hayles that suggests a constantly permeable, fluid and extended subjectivity, displacing the boundaries between human and other. In doing so, we propose a posthuman concept of empathy in gameplay, and we apply this concept to data from the first author’s 18-month ethnographic field notes of gameplay in the MMORPG World of Warcraft. Exploring these data through our analysis of posthuman empathy, we demonstrate the entanglement of avatar–player, machine–human relationship. We show how empathy allows us to understand this relationship as constantly negotiated and in process, producing visceral reactions in the intra-connected avatar–player subject as well as moments of co-produced in-game action that require ‘affective matching’ between subjective and embodied experiences. We argue that this account of the avatar–player relationship extends research in game culture, providing a horizontal, non-hierarchical discussion of its most necessary interaction