bluuebunny/crossref_metadata_2025_split huggingface dataset:
Trimer stability of Helicobacter pylori HtrA is regulated by a natural mutation in the protease domain
Authors: Zarzecka Urszula , Tegtmeyer Nicole , Sticht Heinrich , Backert Steffen 
Published: May 2023

AbstractThe human pathogen Helicobacter pylori is a major risk factor for gastric disease development. Serine protease HtrA is an important bacterial virulence factor that cleaves the cell junction proteins occludin, claudin-8 and E-cadherin, which causes gastric tissue damage. Using casein zymography, we discovered that HtrA trimer stability varies in clinical H. pylori strains. Subsequent sequence analyses revealed that HtrA trimer stability correlated with the presence of leucine or serine residue at position 171. The importance of these amino acids in determining trimer stability was confirmed by leucine-to-serine swapping experiments using isogenic H. pylori mutant strains as well as recombinant HtrA proteins. In addition, this sequence position displays a high sequence variability among various bacterial species, but generally exhibits a preference for hydrophilic amino acids. This natural L/S171 polymorphism in H. pylori may affect the protease activity of HtrA during infection, which could be of clinical importance and may determine gastric disease development.
Size-effects of metamaterial beams subjected to pure bending: on boundary conditions and parameter identification in the relaxed micromorphic model
Authors: Sarhil Mohammad , Scheunemann Lisa , Schröder Jörg , Neff Patrizio 
Published: May 2023

AbstractIn this paper we model the size-effects of metamaterial beams under bending with the aid of the relaxed micromorphic continuum. We analyze first the size-dependent bending stiffness of heterogeneous fully discretized metamaterial beams subjected to pure bending loads. Two equivalent loading schemes are introduced which lead to a constant moment along the beam length with no shear force. The relaxed micromorphic model is employed then to retrieve the size-effects. We present a procedure for the determination of the material parameters of the relaxed micromorphic model based on the fact that the model operates between two well-defined scales. These scales are given by linear elasticity with micro and macro elasticity tensors which bound the relaxed micromorphic continuum from above and below, respectively. The micro elasticity tensor is specified as the maximum possible stiffness that is exhibited by the assumed metamaterial while the macro elasticity tensor is given by standard periodic first-order homogenization. For the identification of the micro elasticity tensor, two different approaches are shown which rely on affine and non-affine Dirichlet boundary conditions of candidate unit cell variants with the possible stiffest response. The consistent coupling condition is shown to allow the model to act on the whole intended range between macro and micro elasticity tensors for both loading cases. We fit the relaxed micromorphic model against the fully resolved metamaterial solution by controlling the curvature magnitude after linking it with the specimen’s size. The obtained parameters of the relaxed micromorphic model are tested for two additional loading scenarios.
New Calculation Software for Analytic Support Structure Optimization in Metal Additive Manufacturing
Authors: Tiefnig Raphael , Haas Franz 
Published: May 2023

AbstractPowder based additive manufacturing systems often require support structures for overhanging geometries and thermal dissipation. On the one hand, the support material should be reduced to a minimum. On the other hand, the stiffness of the structures can be used as a fixture for post-processing. The contribution presents a unique analytic model to determine the stresses occurring in the support structures during post-processing. FEM simulations with different support types are carried out to validate the new calculation model. The results of this analysis subsequently serve as basis for dimensioning the support elements of complex and large parts. By specifying a machining process, it is possible to determine the required dimensions of the support structure (e.g. block, rod, or cross). The aim of this optimization process is to reduce machining time, material consumption and post-processing costs. The results of this contribution and the new software help to implement direct machining into industrial 3D printing processes.
The impact of emotionally challenging situations on medical students’ professional identity formation
Authors: Lönn Annalena , Weurlander Maria , Seeberger Astrid , Hult Håkan , Thornberg Robert , Wernerson Annika 
Published: May 2023

AbstractIn their interactions with patients and health care professionals during work-based learning, medical students are known to experience emotionally challenging situations that can evoke negative feelings. Students have to manage these emotions. Students learn and develop their professional identity formation through interactions with patients and members of the healthcare teams. Earlier studies have highlighted the issues involved with processing emotionally challenging situations, although studies concerning learning and professional identity formation in response to these experiences are rare. In this study, we explored medical students’ experiences of emotionally challenging situations in work-based learning, and the impact these experiences had on forming medical students’ professional identities. We conducted an analysis of narrative data (n = 85), using a constructivist grounded theory approach. The narratives were made up of medical students’ reflective essays at the end of their education (tenth term). The analysis showed that students’ main concern when facing emotionally challenging situations during their work-based education was the struggle to achieve and maintain a professional approach. They reported different strategies for managing their feelings and how these strategies led to diverse consequences. In the process, students also described arriving at insights into their own personal needs and shortcomings. We consider this development of self-awareness and resulting self-knowledge to be an important part of the continuously ongoing socialization process of forming a professional identity. Thus, experiencing emotionally challenging situations can be considered a unique and invaluable opportunity, as well as a catalyst for students’ development. We believe that highlighting the impact of emotions in medical education can constitute an important contribution to knowledge about the process of professional identity formation. This knowledge can enable faculty to provide students with more effective and sufficient support, facilitating their journey in becoming physicians.
Time pattern variation of alien plant introductions in an insular biodiversity hotspot: the Balearic Islands as a case study for the Mediterranean region
Authors: Cerrato M. D. , Cortés-Fernández I. , Ribas-Serra A. , Mir-Rosselló P. M. , Cardona C. , Gil L. 
Published: May 2023

AbstractAllochthonous plant species are considered among the main environmental issues worldwide, being especially accused in the Mediterranean basin. The present study aims to update Balearic Alien Flora and discuss its time and spatial variation and invasiveness. Information regarding allochthonous plant records of the Balearic Islands were gathered and analysed based on published checklists and online databases. For each species several general traits were assigned based on previous references to characterise the alien Balearic Flora. Records of allochthonous species between 1827 and 2023 indicate that Alien Balearic Flora is composed of 624 taxa recorded unevenly among islands, with lower records in smaller islands. Alien flora is mainly composed of therophytes and phanerophytes being held mainly in human related habitats. Introduction pathway is mainly ornamental, with over 50% of taxa entering through gardening and horticultural practices. Main biogeographical origins are American, Mediterranean, Euroasiatic and Cape origins. Invasive status of Balearic alien flora shows that 44% of all taxa can be regarded as casual, while 35% are naturalised, and 17% can be considered invasive, being the latter increased in smaller islands. Time variations trends starting mainly in the 70 s and predictive models show that alien species increase exponentially, being the most represented taxa from synanthropic habitats, introduced as ornamentals, lianas, phanerophytes and therophytes from Cactaceae, Asteraceae and Leguminosae families. The results of the present study can serve as a model to facilitate the scientifically informed decision making and management of plant invasions both in the Balearic Islands and other continental insular systems and Mediterranean regions.
Electronic and ring size effects of N-heterocyclic carbenes on the kinetics of ligand substitution reactions and DNA/protein interactions of their palladium(II) complexes
Authors: Omondi Reinner O. , Jaganyi Deogratius , Ojwach Stephen O. 
Published: May 2023

AbstractThe synthesis, substitution kinetics and DNA/BSA interactions of four cationic Pd(II) complexes [Pd(1)Cl]BF4 (Pd1), [Pd(2)Cl]BF4 (Pd2), [Pd(3)Cl]BF4 (Pd3) and [Pd(4)Cl]BF4 (Pd4), derived from the reaction of [PdCl2(NCCH3)2] with ligands 2,6-bis(3-methylimidazolium-1-yl)pyridine dibromide (1), 2,6-bis(3-ethylimidazolium-1-yl)pyridine dibromide (2), 2,6-bis(1-methylimidazole-2-thione)pyridine (3), and 2,6-bis(1-ethylimidazole-2-thione)pyridine (4), respectively are reported. The complexes were characterised by various spectroscopic techniques and single crystal X-ray diffraction for compound Pd2. Kinetic reactivity of the complexes with the biologically relevant nucleophiles thiourea (Tu), L-methionine (L-Met) and guanosine 5′-monophosphate sodium salt (5’-GMP) was in the order: Pd1 > Pd2 > Pd3 > Pd4, which was largely dependent on the electronic and ring size of the chelate ligands, consistent with Density functional theory (DFT) simulations. The interactions of the complexes with calf thymus DNA (CT-DNA) and bovine serum albumin (BSA) binding titrations showed strong binding. Both the experimental and in silico data reveal CT-DNA intercalative binding mode.
Graphical abstract
Variability of prey preferences and uptake of anthropogenic particles by juvenile white seabream in a coastal lagoon nursery ground
Authors: Müller Carolin , Erzini Karim , Dudeck Tim , Cruz Joana , Corona Luana Santos , Abrunhosa Felipe Eloy , Afonso Carlos Manuel Lourenço , Mateus Miguel Ângelo Franco , Orro Cristina , Monteiro Pedro , Ekau Werner 
Published: May 2023

AbstractMarine plastic litter, originating from land-based sources, enters the marine environment by passing through coastal ecosystems such as lagoons and estuaries. As early life history stages (ELHS) of many commercially important fish species rely on these transitional areas as nursery grounds, we hypothesized that they encounter a spatial gradient of habitat quality and pollution from inner to outer parts of their vital environment. With sizes < 5 mm, anthropogenic particles (AP), among them microplastic (MP) fibers and fragments, entail a high bioavailability for ELHS of fish, potentially facilitating AP uptake at early developmental stages which may have implications for their survival and growth. This study provides a contextualization baseline between feeding preferences and uptake of AP by the white seabream Diplodus sargus (Linnaeus, 1758) in an estuarine nursery ground on the southern coast of Portugal. Juvenile fish showed a generalized, omnivorous feeding mode with differences in trophic resource utilization between individuals collected at distinct seagrass meadows in the lagoon. A total of 23.13% of the fish (n = 147) were detected with AP in the gastrointestinal tract, and the mean number of AP per AP-feeding individual was 1.64 ± 1.04, with anthropogenic fibers (n = 47) occurring more frequently than fragments (n = 9). Knowledge of the underlying factors for MP ingestion will be greatly enhanced by considering environmental conditions along with species-stage and life-stage specific feeding modes and prey preferences which shape the uptake probability of anthropogenic fibers and fragments.
Differentiated experiences of financial precarity and lived precariousness among international students in Australia
Authors: Mulvey Benjamin , Morris Alan , Ashton Luke 
Published: May 2023

AbstractEmpirical research on international student migrants has sometimes homogenised this group, framing it as predominantly made up of privileged members of the global middle-class. This has led to calls to acknowledge and address the precarity faced by international students in their respective host countries more comprehensively. This study aims to explore how levels of financial precarity vary among international students in Australia, and how this in turn contributes to varying levels of precariousness in the personal spheres of students’ lives. In doing so, we centre and refine the concept of precarity for use in studies of internationally mobile students, arguing for its use as a ‘relational nexus’, bridging financial precarity and broader lived experiences. Drawing on a large-scale survey and semi-structured interviews with 48 students, we emphasise the linkages between financial precarity and precariousness as a socio-ontological experience, explored through the examples of time poverty, physical and mental wellbeing, and relationships.
Combined effects of two abiotic stressors (salinity and temperature) on a laboratory-simulated population of Daphnia longispina
Authors: Venâncio Cátia , Wijewardene Lishani , Ribeiro Rui , Lopes Isabel 
Published: May 2023

AbstractSea level rise is expected to continue apace, with a concomitant rise in temperature on the globe's surface. Natural populations genetic pool compromised by increased salinity would contribute to decrease resilience under future temperature changes. Therefore, this work aimed to understand the long-term effects of salinization on the genetic diversity of a cladoceran-simulated laboratory population under different temperature regimes. For that, six clonal lineages of the cladoceran Daphnia longispina were chosen based on their reported differential lethal sensitivity (LCx) to salinity. The chronic experiment was initiated when each individual clonal lineage reached the population’s carrying capacity, and then were exposed to the LC70,48 h for the most tolerant clonal lineage of D. longispina (corresponding to 5.91 mS/cm) to 17°C, 20°C and 23°C for at least 30 days. Salinity affected D. longispina survival and reproduction, with the disappearance of salt-tolerant earlier than salt-sensitive lineages after chronic exposures. Different sensitivity ranks were observed for clonal lineages when comparing short-term and chronic survival, most probably due to acclimation-driven population recovery. Non-optimal tested temperatures (17°C and 23°C) enhanced negative effects of salinity through loss of the most sensitive clonal lineages, suggesting a potential future synergistic effect between both abiotic factors.
Synthesising Programs with Non-trivial Constants
Authors: Abate Alessandro , Barbosa Haniel , Barrett Clark , David Cristina , Kesseli Pascal , Kroening Daniel , Polgreen Elizabeth , Reynolds Andrew , Tinelli Cesare 
Published: May 2023

AbstractProgram synthesis is the mechanised construction of software. One of the main difficulties is the efficient exploration of the very large solution space, and tools often require a user-provided syntactic restriction of the search space. While useful in general, such syntactic restrictions provide little help for the generation of programs that contain non-trivial constants, unless the user is able to provide the constants in advance. This is a fundamentally difficult task for state-of-the-art synthesisers. We propose a new approach to the synthesis of programs with non-trivial constants that combines the strengths of a counterexample-guided inductive synthesiser with those of a theory solver, exploring the solution space more efficiently without relying on user guidance. We call this approach CEGIS($$\mathcal {T}$$
T
), where $$\mathcal {T}$$
T
is a first-order theory. We present two exemplars, one based on Fourier-Motzkin (FM) variable elimination and one based on first-order satisfiability. We demonstrate the practical value of CEGIS($$\mathcal {T}$$
T
) by automatically synthesising programs for a set of intricate benchmarks. Additionally, we present a case study where we integrate CEGIS($$\mathcal {T}$$
T
) within the mature synthesiser CVC4 and show that CEGIS($$\mathcal {T}$$
T
) improves CVC4’s results.
Flux Globalization Based Well-Balanced Central-Upwind Schemes for Hydrodynamic Equations with General Free Energy
Authors: Chen Xi , Kurganov Alexander , Liu Yongle 
Published: May 2023

AbstractWe develop flux globalization based well-balanced central-upwind schemes for hydrodynamic equations with general free energy. The proposed schemes are well-balanced in the sense that they are capable of exactly preserving quite complicated steady-state solutions and also exactly capturing traveling waves, even when vacuum regions are present. In order to accurately track interfaces of the vacuum regions and near vacuum parts of the solution, we use the technique introduced in Chertock et al. (J Sci Comput 90:Paper No. 9, 2022) and design a hybrid approach: inside the no vacuum regions, we use the flux globalization based well-balanced central-upwind scheme, while elsewhere we implement the central-upwind scheme similar to the one proposed in Bollermann et al. (J Sci Comput 56:267–290, 2013) in the context of wet/dry fronts in the shallow water equations. The advantages of the proposed schemes are demonstrated on a number of challenging numerical examples.
Climbing the 'ladder of intrusiveness': the Italian government's strategy to push the Covid-19 vaccination coverage further
Authors: Profeti Stefania , Toth Federico 
Published: May 2023

AbstractIn all Western countries, the vaccination campaign against COVID-19 encountered some resistance. To overcome vaccine inertia and hesitancy, governments have used a variety of strategies and policy instruments. These instruments can be placed on a 'ladder of intrusiveness', starting from voluntary tools based on simple information and persuasion, through material incentives and disincentives of varying nature and magnitude, to highly coercive tools, such as lockdown for the unvaccinated and the introduction of the vaccination mandate. Italy's experience during the vaccination campaign against Covid provides an ideal observational point for starting to investigate this issue: not only was Italy among the top countries with the highest percentage of people vaccinated at the beginning of 2022, but—at least compared to other European countries—it was also one of the countries that had gradually introduced the most intrusive measures to increase vaccination compliance. In the article the different steps of the ‘intrusiveness ladder’ are presented, providing examples from various countries, and then tested on the Italian Covid-19 vaccination campaign between 2021 and the first months of 2022. For each phase of the campaign, the instrument mixes adopted by the Italian government are described, as well as the contextual conditions that led to their adoption. In the final section, an assessment of the composition and evolution of the Italian vaccination strategy is provided, based on the following criteria: legitimacy, feasibility, effectiveness, internal consistency and strategic coherence. Conclusions highlight the pragmatic approach adopted by the Italian government and underline the effects—both positive and negative—of scaling up the intrusiveness ladder.
New optical solitons for perturbed stochastic nonlinear Schrödinger equation by functional variable method
Authors: Mohamed E. M. , El-Kalla I. L. , Tarabia A. M. K. , Kader A. H. Abdel 
Published: May 2023

AbstractIn this paper, the functional variable method is used to obtain new optical soliton solutions for the perturbed stochastic nonlinear Schrödinger equation with generalized anti-cubic nonlinearity and multiplicative white noise. Using some transformations, new rational, Jacobi elliptic, Weierstrass, and hyperbolic stochastic solutions are obtained. Several optical soliton solutions were proposed, including dark, bright, and compacton soliton solutions. Graphical presentations of the obtained optical soliton solutions are shown to illustrate some of its physical parameters.
Good guesses as accuracy-specificity tradeoffs
Authors: Skipper Mattias 
Published: May 2023

AbstractGuessing is a familiar activity, one we engage in when we are uncertain of the answer to a question under discussion. It is also an activity that lends itself to normative evaluation: some guesses are better than others. The question that interests me here is what makes for a good guess. In recent work, Dorst and Mandelkern have argued that good guesses are distinguished from bad ones by how well they optimize a tradeoff between accuracy and specificity. Here I argue that Dorst and Mandelkern’s implementation of this idea fails to satisfy some plausible constraints on good guesses, and I develop an alternative implementation that satisfies the relevant constraints. The result is a new account of good guesses which retains the positive aspects of Dorst and Mandelkern’s proposal, but without the drawbacks.
INAR approximation of bivariate linear birth and death process
Authors: Chen Zezhun , Dassios Angelos , Tzougas George 
Published: May 2023

AbstractIn this paper, we propose a new type of univariate and bivariate Integer-valued autoregressive model of order one (INAR(1)) to approximate univariate and bivariate linear birth and death process with constant rates. Under a specific parametric setting, the dynamic of transition probabilities and probability generating function of INAR(1) will converge to that of birth and death process as the length of subintervals goes to 0. Due to the simplicity of Markov structure, maximum likelihood estimation is feasible for INAR(1) model, which is not the case for bivariate and multivariate birth and death process. This means that the statistical inference of bivariate birth and death process can be achieved via the maximum likelihood estimation of a bivariate INAR(1) model.
Convergence rate of multiple-try Metropolis independent sampler
Authors: Yang Xiaodong , Liu Jun S. 
Published: May 2023

AbstractThe multiple-try Metropolis method is an interesting extension of the classical Metropolis–Hastings algorithm. However, theoretical understanding about its usefulness and convergence behavior is still lacking. We here derive the exact convergence rate for the multiple-try Metropolis Independent sampler (MTM-IS) via an explicit eigen analysis. As a by-product, we prove that an naive application of the MTM-IS is less efficient than using the simpler approach of “thinned” independent Metropolis–Hastings method at the same computational cost. We further explore more variants and find it possible to design more efficient algorithms by applying MTM to part of the target distribution or creating correlated multiple trials.