Central Problem Research Articles

Utilization of a natural language processing-based approach to determine the composition of artifact residues

BackgroundDetermining the composition of artifact residues is a central problem in ancient residue metabolomics. This is done by comparing mass spectral features in common with an experimental artifact and an ancient artifact (standard method). While this method is simple and straightforward, we sought to increase the accuracy of predicting which plant species had been used in which artifacts.ResultsHere, we introduce an algorithm (new method) based on ideas from the field of natural language processing (NLP) to solve this problem. We tested our strategy on a set of modern clay pipes. To limit biases, we were not provided information on which plant species had been smoked in which clay pipes. The results indicate that our new method performed 12.5% better than the standard method in predicting the plant species smoked in each artifact.ConclusionsUtilizing an NLP-based approach, we developed a robust algorithm for characterizing the composition of artifact residues. This work also discusses other general applications in which our algorithm could be used in the field of metabolomics, such as datasets where there are a limited number of replicates.

Exploring Journey Experiences of Disabled Passengers in Using Public Transport

This study aims to enhance the understanding of disabled passengers' experiences with public transport by addressing the challenges in measuring their satisfaction and service quality. The central problem is the difficulty in accurately assessing and improving the service quality for disabled passengers, given the diverse needs and barriers they face. Utilizing the SERVQUAL model, which focuses on Tangibility, Reliability, Responsiveness, Assurance, and Empathy, the study identifies and evaluates these key dimensions in the context of public transport services. Findings reveal both unique needs and commonalities among different disability groups: hearing-impaired passengers require visual signals and nonverbal communication, visually impaired passengers need clear auditory announcements and staff assistance, and physically disabled passengers require accessible infrastructure and supportive services. Commonalities include the appreciation for reliable train schedules, cleanliness, and the need for empathetic and responsive staff. Based on these insights, recommendations are provided to enhance service quality by improving physical accessibility features, enhancing communication methods, and providing targeted staff training. Implementing these recommendations will address specific needs and improve the overall satisfaction of disabled passengers, contributing to a more inclusive and effective public transport system. Future work should focus on integrating additional models and exploring other key variables to uncover further insights into service quality and passenger satisfaction. This approach will offer a more comprehensive understanding of how various factors interact and contribute to a more inclusive and effective public transport system.

Solving the fuzzy p-hub center problem using imperialist competitive algorithm

Solving the fuzzy p-hub center problem using imperialist competitive algorithm

Mechanical Profiling of Biopolymer Condensates through Acoustic Trapping.

Characterizing the mechanical properties of single colloids is a central problem in soft matter physics. It also plays a key role in cell biology through biopolymer condensates, which function as membraneless compartments. Such systems can also malfunction, leading to the onset of a number of diseases, including many neurodegenerative diseases; the functional and pathological condensates are commonly differentiated by their mechanical signature. Probing the mechanical properties of biopolymer condensates at the single particle level has, however, remained challenging. In this study, we demonstrate that acoustic trapping can be used to profile the mechanical properties of single condensates in a contactless manner. We find that acoustic fields exert the acoustic radiation force on condensates, leading to their migration to a trapping point where acoustic potential energy is minimized. Furthermore, our results show that the Brownian motion fluctuation of condensates in an acoustic potential well is an accurate probe for their bulk modulus. We demonstrate that this framework can detect the change in the bulk modulus of polyadenylic acid condensates in response to changes in environmental conditions. Our results show that acoustic trapping opens up a novel path to profile the mechanical properties of soft colloids at the single particle level in a non-invasive manner with applications in biology, materials science, and beyond.

An artificial bee colony optimization algorithms for solving fuzzy capacitated logistic distribution center problem

This paper presents a methodological approach to solving the fuzzy capacitated logistic distribution center problem, with a focus on the optimal selection of distribution centers to meet the demands of multiple plants. The distribution centers are characterized by fixed costs and capacities, while plant demands are modeled using fuzzy triangular membership functions. The problem is mathematically formulated by converting fuzzy demands into crisp values, providing a structured framework for addressing uncertainty in logistic planning. To support future research and facilitate comparative analysis, 20 benchmark problems were generated, filling a gap in the existing literature. Three distinct artificial bee colony algorithm variants were hybridized with a heuristic: one using the best solution per iteration, another incorporating chaotic mapping and adaptive procedures, and the third employing convergence and diversity archives. An experimental design based on Taguchi's orthogonal arrays was employed for optimizing the algorithm parameters, ensuring systematic exploration of the solution space. The developed methods offer a comprehensive toolkit for addressing complex, uncertain demands in logistic distribution, with code provided for reproducibility.Key contributions include:•Development of a fuzzy model for the selection of distribution centers with fixed costs and capacities under uncertain plant demands.•Generation of 20 benchmark problems to advance research in the fuzzy capacitated logistic distribution center problem domain.•Integration of a heuristic approach with three distinct ABC algorithm variants, each contributing unique methodological insights.

Anderson Localization of Walking Droplets

Understanding the ability of particles to maneuver through disordered environments is a central problem in innumerable settings, from active matter and biology to electronics. Macroscopic particles ultimately exhibit diffusive motion when their energy exceeds the characteristic potential barrier of the random landscape. In stark contrast, wave-particle duality causes electrons in disordered media to come to rest even when the potential is weak—a remarkable phenomenon known as Anderson localization. Here, we present a hydrodynamic active system with wave-particle features, a millimetric droplet self-guided by its own wave field over a submerged random topography, whose dynamics exhibits localized statistics analogous to those of electronic systems. Consideration of an ensemble of particle trajectories reveals a suppression of diffusion when the guiding wave field extends over the disordered topography. We rationalize mechanistically the emergent statistics by virtue of the wave-mediated resonant coupling between the droplet and topography, which produces an attractive wave potential about the localization region. This hydrodynamic analog, which demonstrates how a classical particle may localize like a wave, suggests new directions for future research in various areas, including active matter, wave localization, many-body localization, and topological matter. Published by the American Physical Society 2024

Multiperiod Dynamic Portfolio Choice: When High Dimensionality Meets Return Predictability

Multiperiod portfolio choice is the central problem in active asset management. Multiperiod dynamic portfolios are notoriously difficult to solve, especially when there are hundreds of tradable assets as well as a large number of state variables. In this article, we develop a novel two-step methodology to solve the multiperiod dynamic portfolio choice problem with high dimensional assets in the presence of return predictability conditional on a large number of state predictors. Specifically, in the first step, we propose the new Risk-Premium Projected-PCA (RP-PPCA) method to reduce the dimension of tradable assets. This method achieves Dimension Reduction (DR) by estimating latent factors with explanatory power in both time series variation and expected return in high-dimension-low-sample-size data. In the second step, we use dynamic programming to solve the multiperiod portfolio choice problem, and in each recursive step, we adopt an Adjusted semiparametric Model Averaging (AMA) method to avoid the curse of dimensionality associated with a large set of state variables while remaining computationally efficient. Thus, we name this two-step approach DRAMA, which stands for a combination of a new dimension reduction method and an adjusted semiparametric model averaging method. Analytically, we show that the portfolios constructed by the DRAMA are approximately optimal under mild assumptions. Moreover, our numerical results based on empirical data from US stock markets show that the proposed portfolios have excellent out-of-sample performances.

Soft cells and the geometry of seashells.

A central problem of geometry is the tiling of space with simple structures. The classical solutions, such as triangles, squares, and hexagons in the plane and cubes and other polyhedra in three-dimensional space are built with sharp corners and flat faces. However, many tilings in Nature are characterized by shapes with curved edges, nonflat faces, and few, if any, sharp corners. An important question is then to relate prototypical sharp tilings to softer natural shapes. Here, we solve this problem by introducing a new class of shapes, the soft cells, minimizing the number of sharp corners and filling space as soft tilings. We prove that an infinite class of polyhedral tilings can be smoothly deformed into soft tilings and we construct the soft versions of all Dirichlet-Voronoi cells associated with point lattices in two and three dimensions. Remarkably, these ideal soft shapes, born out of geometry, are found abundantly in nature, from cells to shells.

The diameter of sum basic equilibria games

We study the sum basic network creation game introduced in 2010 by Alon, Demaine, Hajiaghai and Leighton. In this game, an undirected and unweighted graph G is said to be a sum basic equilibrium if and only if, for every edge uv and any vertex v′ in G, swapping edge uv with edge uv′ does not decrease the total sum of the distances from u to all the other vertices. This concept lies at the heart of the network creation games, where the central problem is to understand the structure of the resulting equilibrium graphs, and in particular, how well they globally minimize the diameter. In this sense, in 2013 Alon et al. showed an upper bound of 2O(log⁡n) on the diameter of sum basic equilibria, and they also proved that if a sum basic equilibrium graph is a tree, then it has diameter at most 2. In this paper, we prove that the upper bound of 2 also holds for bipartite graphs and even for some non-bipartite classes like block graphs and cactus graphs.

Local Non Abelian Class Field Theory

The “local class field theory”, which can be defined as the description of the extensions of a given local field K in terms of the algebraic and analytic objects depending ony on the base K is one of the central problems of modern number theory. The theory developed for the abelian extensions, around the fundamental works of Artin and Hasse in the first quarter of the 20th century. It is natural to ask if one could construct this theory including the non-abelian extensions of the base field. There are two approches to this problem. One approach is based on the ideas of Langlands, and the other on Koch. Koch’s method was later generalized by Fesenko and Koch-de Shalit for some non-abelian extensions of the base field. On the other hand, Ikeda and Serbest extended Fesenko’s works to construct a non-abelian local class field theory. But there is a restriction for the base field K. In this study, we extended Ikeda-Serbest’s construction of the local reciprocity map for a certain local field to any local field. Also we have shown that the extended map satisfies the certain functoriality and ramification theoretic properties.

‘It’s like Central Park’: conceptualising teacher residencies as a democratic hub

ABSTRACT In this conceptual paper, we offer a framework to examine how residency programmes can critically reflect upon their existence and presence as a democratic hub. As a model of teacher preparation that blends theory and university coursework with practice, residency programmes are designed to prepare and diversify the teacher workforce for a context-specific setting that calls upon universities to partner closely with local districts. We see the need for a reflective conceptualisation of residencies to offer a tool for considering how and why residencies are created. In conceptualising teacher residency programmes as democratic hubs rather than institutional programmes, we draw on the metaphor of Central Park in New York City to discuss the permeability of boundaries and accessibility to all. We centre our framework on three pillars: a) decentralising knowledge; b) historicising knowledge; and c) co-creating knowledge. This study has implications for addressing a central and longstanding problem in teacher education: the disconnect between academic coursework and fieldwork or the lack of collaboration between schools and universities often referred to as the theory-practice divide. We offer this tool to conceptualise teachers’ residencies so that teacher education can be designed to matter in practice, not only in institutions but for the public good.

WENDY: Covariance dynamics based gene regulatory network inference

Determining gene regulatory network (GRN) structure is a central problem in biology, with a variety of inference methods available for different types of data. For a widely prevalent and challenging use case, namely single-cell gene expression data measured after intervention at multiple time points with unknown joint distributions, there is only one known specifically developed method, which does not fully utilize the rich information contained in this data type. We develop an inference method for the GRN in this case, netWork infErence by covariaNce DYnamics, dubbed WENDY. The core idea of WENDY is to model the dynamics of the covariance matrix, and solve this dynamics as an optimization problem to determine the regulatory relationships. To evaluate its effectiveness, we compare WENDY with other inference methods using synthetic data and experimental data. Our results demonstrate that WENDY performs well across different data sets.

A Decade of Protecting Progress: Ethics Review.

Ethics Review began a decade ago with a mission to identify ethical concerns that hold back innovation and to promote solutions that would move the field forward. Over this time, blood biomarkers for brain pathology and medications that treat that pathology promise to transform research and care. A central problem is that the evidence needed to guide test interpretation and practice is accumulating and there are unanswered questions. At the same time, people living with and at risk for dementia want access to their test results and involvement in their care. We promote dialog among diverse people across many institutions through collaboration with the Advisory Group on Risk Evidence Education for Dementia (AGREEDementia.org). Over the years Ethics Review continues to publish these dialogs and solutions to overcome the paralysis of indecision and ethical concerns.

Integration of democratic values in natural sciences education: A Literature Review of the last 50 Years

This study examines how democratic values have been promoted through natural sciences education over the last 50 years, providing a comprehensive analysis based on a systematic review of relevant literature. The central problem addressed is understanding the role of natural science education in fostering democratic values such as equity, participation, critical thinking, and ethical responsibility. This research aims to identify and analyze strategies, methodologies, and transformative experiences that contribute to the promotion of democratic values. This study employs the PRISMA methodology to ensure a rigorous and structured systematic review. Data were collected from multiple databases using detailed Boolean equations. Tools such as ScientoPy and VOSviewer were used for data preprocessing, clustering, and network visualization, followed by qualitative analysis to categorize the findings. Educational programs in natural sciences have increasingly integrated democratic values, fostering a culture of inclusivity and participation; the incorporation of ICT has enhanced equity and participation, while civic education has been fundamental in developing critical and informed citizens; citizen science initiatives have empowered students to engage in democratic deliberation and address epistemic injustice; cooperative learning methods in science classes have effectively promoted gender equity and inclusion; and emphasis on sustainability and environmental justice in science education has promoted democratic values and empowered students to take action on global challenges. In conclusion, natural science education is an effective vehicle for promoting democratic values, but it is an understudied field. By integrating practices that emphasize inclusivity, critical thinking, and ethical responsibility, science education not only enhances students’ scientific understanding but also prepares them to be active, informed, and responsible citizens.

Criando Startups a Partir de Aprendizagem Baseada em Projetos na Disciplina “ZMV1386 - Biologia Molecular: Desenvolvendo Projetos”

Previous research has highlighted the necessity of enhancing the teaching-learning process, given the demand for a workforce that is proficient in formulating problem-solving strategies. The course in which the current didactic-pedagogical project was applied follows a project-based learning (PBL) approach, wherein students identify a problem within their area of ​​interest and formulate strategies to address it. With the goal of adapting this approach to real-world market conditions, the present proposal was conceived, focusing on simulating the establishment of startups based on developed projects. To achieve this, students initiate the activity by delineating the central problem that the company aims to solve, along with assigning a name to the startup, followed by the allocation of roles, strategic planning and resource identification, a recap of activities based on molecular technologies, projection of tasks for the upcoming semester, and specification of expected outcomes and limitations. In the last class of the course, projects completed over the semester were presented. Remarkable student engagement was observed in the startup simulation, encompassing the creation of websites, slogans, and logos to captivate the end consumer of the product or service. Additionally, an electronic survey was conducted to understand the students’ opinions, and the outcomes served to validate the success of the proposal. These findings further support the idea that active teaching methodologies have the potential to enhance the development of student skills toward problem solving within their future areas of activity.

Unveiling the Hidden Power of Water Services Development Plans

South African Water Services Authorities (WSAs) have been grappling with the challenge of providing sustainable water and sanitation services which is a product of the sector’s inadequate planning and practices systems. Consequently, many communities which are the end-users endure inadequate access to sustainable water and sanitation services. Thus, establishing effective planning mechanisms becomes crucial to ensure the provision of adequate and sustainable water and sanitation services, and this is the central problem of analysis and prescription for this paper. Notably, the paper recommends an already existing systems approach to local governance that takes advantage of Information and Communication Technology (ICT) to drive the modernisation of water and sanitation planning processes which are the Municipal Strategic Self-Assessment (MuSSA) and the Water Services Development Plan (WSDP). Through an emic perspective, systematic search of literature, and document analysis, this paper examines the 2022 MuSSA reports of Western Cape and Gauteng, to identify the challenges faced by the provinces. The findings reveal deficiencies in the Western Cape's investment in asset renewal, infrastructure management, reduction of non-revenue water, and adherence to national standards. Similarly, Gauteng requires comprehensive reforms to address financial instability, asset management, and regulatory compliance. The paper also examines the progress of WSDP development in the 2022-2027 cycle, specifically focusing on the 2022-2023 financial cycle to assess WSAs' compliance. Results indicate that, of 25 WSAs in the Western Cape, only 10 have initiated WSDP development, while 15 lag behind. In Gauteng, only 2 of 9 WSAs have begun the process. Notably, both provinces are behind schedule, having been expected to initiate WSDP development in 2022. The findings of this paper, give an invaluable snippet of the water services planning mechanisms at the local government to ensure proper monitoring and adequate intervention at a local level whilst ensuring the streamlining of resource allocation and recommends that the national government reflects on its shortcomings of ensuring legislative compliance by local government.

Historicizing historicism: Reinhart Koselleck and the periodization of modernity

ABSTRACT Starting from J. Fabian’s critique of anthropology and its study of the ‘primitive’ Other, Fernando Esposito discusses R. Koselleck’s work as a critique of historical practice, not least the practice of periodization. While often understood as ‘merely’ a contribution to the question of temporalities, Koselleck actually aimed to develop a new way of writing and understanding history. Seen in this light, his work on historical time is really about a fundamental theoretical reorientation of the discipline. This fundamental reinvention of history was the central problem Koselleck wrestled with. Based on his personal experience of the Third Reich and the Second World War, he came to the conviction that history had no meaning and no goal, and therefore undertook a historicization of historicism, i.e. a re-evaluation of the way history had been written up to his own times. Koselleck’s historicization of historicism was a decisive chronopolitical act. It was catalyzed by his intention to debunk an unhistorical understanding of history and to replace it with a self-reflective, truly historicist historicism, a metahistory reflecting upon the ‘conditions of possible histories’.

Accuracy of renovo predictions on variants reclassified over time

BackgroundInterpreting the clinical consequences of genetic variants is the central problem in modern clinical genomics, for both hereditary diseases and oncology. However, clinical validation lags behind the pace of discovery, leading to distressing uncertainty for patients, physicians and researchers. This “interpretation gap” changes over time as evidence accumulates, and variants initially deemed of uncertain (VUS) significance may be subsequently reclassified in pathogenic/benign. We previously developed RENOVO, a random forest-based tool able to predict variant pathogenicity based on publicly available information from GnomAD and dbNFSP, and tested on variants that have changed their classification status over time. Here, we comprehensively evaluated the accuracy of RENOVO predictions on variants that have been reclassified over the last four years.Methodswe retrieved 16 retrospective instances of the ClinVar database, every 3 months since March 2020 to March 2024, and analyzed time trends of variant classifications. We identified variants that changed their status over time and compared RENOVO predictions generated in 2020 with the actual reclassifications.ResultsVUS have become the most represented class in ClinVar (44.97% vs. 9.75% (likely) pathogenic and 40,33% (likely) benign). The rate of VUS reclassification is linear and slow compared to the rate of VUS reporting, exponential and currently ~ 30x faster, creating a growing divide between what can be sequenced vs. what can be interpreted. Out of 10,196 VUS variants in January 2020 that have undergone a clinically meaningful reclassification to march 2024, RENOVO correctly classified 82.6% in 2020. In addition, RENOVO correctly identified the majority of the few variants that switched clinically meaningful classes (e.g., from benign to pathogenic and vice versa). We highlight variant classes and clinically relevant genes for which RENOVO provides particularly accurate estimates. In particularly, genes characterized by large prevalence of high- or low-impact variants (e.g., POLE, NOTCH1, FANCM etc.). Suboptimal RENOVO predictions mostly concern genes validated through dedicated consortia (e.g., BRCA1/2), in which RENOVO would anyway have a limited impact.ConclusionsTime trend analysis demonstrates that the current model of variant interpretation cannot keep up with variant discovery. Machine learning-based tools like RENOVO confirm high accuracy that can aid in clinical practice and research.

Editorial: New perspectives on curriculum: Rethinking collaborative enquiry and teachers' professional learning

AbstractIn BERA's 50th anniversary, this special issue of the Curriculum Journal recognises the debt to the work of Lawrence Stenhouse, former BERA President, and founder of the British Curriculum Forum (BCF), and his influence on teachers' work in researching and developing the curriculum. Papers in this issue address what Stenhouse called the central problem of evidence‐informed practice: ‘the gap between our ideas and our aspirations and our attempts to operationalise them’ (Stenhouse, 1975, 2–3). Stenhouse's legacy for curriculum models and thinking, both within the four home countries and internationally, highlights the methodologies and theoretical perspectives that inform teachers as researchers and how we understand and evaluate such frames of reference. Approaches to involving teachers as researchers examined in this collection resonate with BERA's strategic plan to build on its links with practitioners, set in the context of BCF and its work to support teachers' curriculum research.

IMAGES OF ARISTOCRATES AND COMMON PEOPLE IN THE TRAGEDIES OF BENJAMIN JOHNSON

The article describes the interpersonal relationships of various states of society of the «post-Shakespearean» era in the artistic work of the outstanding English playwright and actor Benjamin Johnson. Relying on sources and scientific literature, the author of the article tries to recreate the layer of everyday life in London at the turn of the 16th and 17th centuries, to reveal the problem of the «survival» of actors in the first stationary theater «Globus», their attempts to communicate with aristocrats, the attitude towards famous actors and directors in the English late Middle Ages society The central problem of the research is also the relationship between V. Shaksrip and A. Ferabosko, whose acting troupes shared the «stage» of the «Globus» theater. All these questions are most vividly revealed in Benjamin Johnson’s tragedy «Thrice Crossing the Thames», which was published after his death at the author’s request. The image of English society revealed through the thoughts and worldview of his contemporary is simply amazing. In the author’s opinion, it is also valuable that Benjamin Johnson personally knew V. Shakespeare and A. Ferabosko, the unforgettable young actress Catherine Loster. Research methodology. The content-comparative method, the method of modification of concepts and terms, generalizing and problem-searching methods to reproduce the realities of the era were used to write the article. Conclusion. we see that the place of man and the concept of «humanity» in the English dramaturgy of the «post-Shakespearean» era have changed significantly. In English art, more and more realistic «notes» are felt. Instead of “elevated” and “low” on the pages of books, «street life», «urban slums», relations between new states of society, new social morality come to the English stage. In order to fully feel the depth of these changes, it is worth discovering the realistic human images reproduced by contemporaries of the «post-Neckspearian» era, understanding the criteria of their morality and humanity from the point of view of the author of the dramatic work, who wrote at the crossroads of two great eras.