Central Problem Research Articles

Spatial structure could explain the maintenance of alternative reproductive tactics in tree cricket males.

Trait polymorphisms are widespread in nature, and explaining their stable co-existence is a central problem in ecology and evolution. Alternative reproductive tactics, in which individuals of one or more sex exhibit discrete, discontinuous traits in response to reproductive competition, represent a special case of trait polymorphism in which the traits are often complex, behavioural, and dynamic. Thus, studying how alternative reproductive tactics are maintained may provide general insights into how complex trait polymorphisms are maintained in populations. We construct a spatially explicit individual-based model inspired from extensively collected empirical data to address the mechanisms behind the co-existence of three behavioural alternative reproductive tactics in males of a tree cricket (Oecanthus henryi). Our results show that the co-existence of these tactics over ecological time scales is facilitated by the spatial structure of the landscape they inhabit, which serves to equalise the otherwise unequal mating benefits of the three tactics. We also show that this co-existence is unlikely if spatial aspects of the system are not considered. Our findings highlight the importance of spatial dynamics in understanding ecological and evolutionary processes and underscore the power of integrative approaches that combine models with empirical data.

Online Matching: A Brief Survey

Matching, capturing allocation of items to unit-demand buyers, or tasks to workers, or pairs of collaborators, is a central problem in economics. Indeed, the growing prevalence of matching-based markets, many of which online in nature, has motivated much research in economics, operations research, computer science, and their intersection. This brief survey is meant as an introduction to the area of online matching, with an emphasis on recent trends, both technical and conceptual.

The physics and the biology of the water balance: A personal journey through the critical zone into the water balance

AbstractThe essay describes how a combination of scaling theory from percolation, that relates pore scale flow and transport through catchment scales to global scales (bottom‐up), as well as water fluxes to soil formation and vegetation growth, can be used to support an accurate ecological optimization that (top‐down): solves the central problem of hydrology, that is., “the water balance,” and generates critically important derived quantities, namely streamflow response to climate change, net primary productivity, and plant species richness. Moreover, the essay describes how this particular theoretical approach came to be designed and how it, in retrospect, fits in with the vision of the Committee on Opportunities in the Hydrologic Sciences which met 34 years ago to formulate a research, teaching, and infrastructure guide for the community, and “rebrand our science as a geoscience.” Finally, it demonstrates how the research satisfies the present desires of the community to unite Darwinian and Newtonian scientific methods in the solution of this central problem and how it relates to present research directions in the fields of hydrologic sciences and ecology.

Assessing the risks for stillbirth in São Paulo, Brazil: protocol for a multidisciplinary case–control study – FetRisks

Stillbirth is a fundamental component of childhood mortality, but its causes are still insufficiently understood. This study aims to explore stillbirth risk factors by using a multidisciplinary approach to stimulate...

On the Ethical Priority of Problem Solving in Case‐Based Teacher Ethics: Grounding an Anti‐Oppressive Approach

AbstractA central problem for phronetic case‐based approaches to the ethics of teaching lies in the proper determination of normative ethical problems. Judgments about the character of normative ethical problems depend in part on background beliefs about what is (or is not) of ethical value. Thus, to distinguish genuinely normative ethical problems, teachers seem to first require knowledge of what is of ethical value, which practical problems themselves cannot generate. To resolve this practical and theoretical problem, Nicolas Tanchuk and Alyssa Emery argue for a Deweyan approach to teacher ethics that asserts two central theses: First, negatively, that inductive evidence warrants skepticism about any normative theory grounded in external reasons — (purported) reasons that are actually or possibly disconnected from an agent's motivational set of beliefs, desires, and dispositions. Second, that a cognitive and affective orientation toward solving problems through learning survives skepticism about external ethical reasons, grounding the commitments of many anti‐oppressive teacher educators.

Topological analysis of 3D digital ovules identifies cellular patterns associated with ovule shape diversity.

Tissue morphogenesis remains poorly understood. In plants, a central problem is how the 3D cellular architecture of a developing organ contributes to its final shape. We address this question through a comparative analysis of ovule morphogenesis, taking advantage of the diversity in ovule shape across angiosperms. Here, we provide a 3D digital atlas of Cardamine hirsuta ovule development at single cell resolution and compare it with an equivalent atlas of Arabidopsis thaliana. We introduce nerve-based topological analysis as a tool for unbiased detection of differences in cellular architectures and corroborate identified topological differences between two homologous tissues by comparative morphometrics and visual inspection. We find that differences in topology, cell volume variation and tissue growth patterns in the sheet-like integuments and the bulbous chalaza are associated with differences in ovule curvature. In contrast, the radialized conical ovule primordia and nucelli exhibit similar shapes, despite differences in internal cellular topology and tissue growth patterns. Our results support the notion that the structural organization of a tissue is associated with its susceptibility to shape changes during evolutionary shifts in 3D cellular architecture.

Distributed Energy Dispatch for Geo-Data Centers Port Microgrid

With the development of port automation and artificial intelligence, coordination with multi-geographic data centers (Geo-DCs) has become a viable solution to address the issue of limited port computing resources. This study proposes a distributed energy dispatch method for the port microgrid coordinated with Geo-DCs (Geo-DCPM), aimed at reducing port carbon emissions and operational costs. Consider the single point of failure problem and high construction costs of centralized data centers. Geo-DCs are first introduced to solve the problem of insufficient computing resources in ports. An energy consumption calculation model for Geo-DCs is established, considering the data load delay constraint and the data space transfer constraint caused by specific delay-sensitive loads in the port microgrid. Then, an energy dispatch model (EDM) is constructed for the Geo-DCPM, taking into account carbon capture costs. Moreover, based on mixed-integer linear programming, a distributed algorithm is proposed to solve the EDM problem. Finally, the simulation results verify the effectiveness of the proposed method. Compared with the centralized algorithm, the packet loss rate of the distributed algorithm combined with Geo-DCs is significantly lower, reduced by about 70%.

Combining Transition Path Sampling with Data-Driven Collective Variables through a Reactivity-Biased Shooting Algorithm.

Rare event sampling is a central problem in modern computational chemistry research. Among the existing methods, transition path sampling (TPS) can generate unbiased representations of reaction processes. However, its efficiency depends on the ability to generate reactive trial paths, which in turn depends on the quality of the shooting algorithm used. We propose a new algorithm based on the shooting success rate, i.e., reactivity, measured as a function of a reduced set of collective variables (CVs). These variables are extracted with a machine learning approach directly from TPS simulations, using a multitask objective function. Iteratively, this workflow significantly improves the shooting efficiency without any prior knowledge of the process. In addition, the optimized CVs can be used with biased enhanced sampling methodologies to accurately reconstruct the free energy profiles. We tested the method on three different systems: a two-dimensional toy model, conformational transitions of alanine dipeptide, and hydrolysis of acetyl chloride in bulk water. In the latter, we integrated our workflow with an active learning scheme to learn a reactive machine learning-based potential, which allowed us to study the mechanism and free energy profile with an ab initio-like accuracy.

Transgenerational Frontiers: The Capabilities Approach And the New Challenge of Justice

ABSTRACT The aim of the paper is to confront some challenges raised by intergenerational justice from the perspective of Martha Nussbaum’s capabilities approach. After having sketched her account, the essay deals with some objections to it from an environmental perspective, arguing that, contrary to some critics, it can be a valuable basis for reflecting on our duties towards future generations. More precisely, I focus on how the CA provides promising insights to address two central problems of intergenerational ethics: 1) the so-called ‘circumstances of justice;’ 2) the problem of the asymmetry between present and future generations. In both cases, I argue that the philosophical anthropology underlying the CA is better suited than the contractualist one to include future generations into the realm of justice and ground our motivation to care for them. After underlining the potential of the CA, in the concluding remarks I will underline a potential flaw of this theory, i.e. the lack of guidance when it comes to the trade-offs between our rights and well-being and those of the unborn.

AdvNF: Reducing mode collapse in conditional normalising flows using adversarial learning

Deep generative models complement Markov-chain-Monte-Carlo methods for efficiently sampling from high-dimensional distributions. Among these methods, explicit generators, such as Normalising Flows (NFs), in combination with the Metropolis Hastings algorithm have been extensively applied to get unbiased samples from target distributions. We systematically study central problems in conditional NFs, such as high variance, mode collapse and data efficiency. We propose adversarial training for NFs to ameliorate these problems. Experiments are conducted with low-dimensional synthetic datasets and XY spin models in two spatial dimensions.

Prudentes sicut serpentes: Dissimulation and Concealment in Japanese and Chinese Missions in the Seventeenth Century

This volume aims to explore the concepts of hypocrisy and dissimulation, conceived in the framework of the ‘tensions at the heart of Christian teaching and experience’. This tension primarily points towards a conflict between ideal and lived practice; however, in certain circumstances, dissimulation and deceit might be understood as legitimate responses to a given situation. This article examines significant aspects of dissimulation in the specific case of early modern missions in China and Japan at the end of the sixteenth and throughout the seventeenth century, where missionaries often had to resort to disguise and concealment. Many of them had to overcome immense difficulties just to enter the country; some had to evangelize in secret, living in constant fear and facing ongoing persecution. In these territories, the ‘policy of deceit’ therefore became a relevant part of the proselytizing enterprise. I examine these practices of dissimulation with regard to evangelization strategies, and relate them to the sincerity and the confession of the faith, two of the central problems of the Christian credo. I argue that dissimulation was perceived, by the missionaries, as a legitimate and tactical response to the challenging and complex circumstances of the Japanese and Chinese missions in this period.

Проявления латентного цифрового экстремизма в молодежной среде

The article deals with the psychological aspects of ensuring the safety of minors from their involvement in extremist activities in the modern world. The age-related psychological characteristics of the personality of minors, as well as the conditions in which their life values, attitudes and worldview in general are formed, are systematically and comprehensively considered. The central problem discussed in the work is latent extremism, which is formed and spread through the means of modern communication technologies. The main conductor of the spread of extremist ideas for young people in general and minors in particular is the Internet with its ability to exchange information and have an indirect impact on the psyche. The role of latent extremism in the formation of a proto-extremist environment, which is the previous stage in the formation of a full-fledged extremist criminal environment, is noted.

Morita equivalence and globalization for partial Hopf actions on nonunital algebras

In this work, we investigate partial actions of a Hopf algebra [Formula: see text] on nonunital algebras and the associated partial smash products, with the objective of providing a framework where one may obtain results for both [Formula: see text]-algebras with local units and [Formula: see text]-categories. We show that our partial actions correspond to nonunital algebras in the category of partial representations of [Formula: see text]. The central problem of existence of a globalization for a partial action is studied in detail, and we provide sufficient conditions for the existence (and uniqueness) of a minimal globalization for associative algebras in general. Extending previous results by Abadie, Dokuchaev, Exel and Simon, we define Morita equivalence for partial Hopf actions, and we show that if two symmetrical partial actions are Morita equivalent then their standard globalizations are also Morita equivalent. Particularizing to the case of a partial action on an algebra with local units, we obtain several strong results on equivalences of categories of modules of partial smash products of algebras and partial smash products of [Formula: see text]-categories.

Robust reverse 1-center problems on trees with interval costs

This paper concerns the problem of reducing the edge lengths of a tree in a minimum cost way such that the 1-center function at a predetermined vertex is at most a given threshold value. Moreover, it is assumed that the costs of reducing edge lengths are not exactly determined, but they are estimated within intervals and their total deviation is limited within a given bound. This problem is called the robust reverse 1-center problem on trees with interval costs. We first reformulate the problem as a Stackelberg game and translate it into a univariate optimization problem. Based on the special properties of the feasible set, we can state the corresponding problem as a parameterized minimum cost flow problem. Then we develop an algorithm that solves the problem in O ( n 2 log ⁡ n ) time due to the convexity of the univariate objective function. We finally discuss the problem of improving the international transportation network in Iran as a real-life application.

Stability condition for nilpotent singularities by its complex separatrices

This work is focused in the center problem for nilpotent singularities of differential systems in the plane. Although there are involved methods to approach the center problem in this work, we present a new stability criteria based on the existence of the complex separatrices passing through the singular point, and independent of the normal form. The algebraic method needs only the computation of such complex separatrices up to certain order, which can be done with a computer algebra package.

Finite Freedom and its split from the Absolute in Schelling’s Bruno

Abstract The dialogue Bruno of 1802 is arguably the natural starting point for any investigation on the concepts of finitude, evil and human freedom in Schelling’s middle metaphysics. In this dialogue the author elaborates for the first time in his system a concept of freedom and independence of the finite, which extends via his reformulation in Philosophy and Religion of 1804 to the Freedom Essay of 1809 and beyond to the works of 1810 and 1811 – Stuttgart Private Lectures and The Ages of the World. The central ontological problem of the dialogue relates to the possibility of a separation between the absolute and the world as space of finite beings, which, according to the system of identity first presented in 1801, cannot exist as such. The question we will then address concerns the status of the finite as such and how would it be possible to admit both its existence for consciousness and the positing of an absolute and infinite principle of philosophy. We will show how Schelling’s interest shifts, almost unintentionally, from the infinite principle to the finite as such, as a principle of freedom and self-initiation independent of the real.

Constitutional foundations of local self-government in Ukraine

The constitutional foundations of local self­government in Ukraine are norms-principles reflected in more than 20 articles of the Constitution of Ukraine. Norms establishing the legal, organizational, material and financial foundations of local self-government provide for the establishment of a democratic decentralized management system, based on independent territorial communities, local self-government bodies, which are entrusted with the decision of all issues of local importance. Real effective local self-government is possible only in the presence of certain conditions that have objectively developed in society, and which collectively form the basis of local self-government. The basics of local self­government create the foundation, that is, the foundation on which the entire system of local self-government is built. One of the fundamental foundations of local self-government is the participation of citizens in the social and political life of the state. The topicality of the topic is due primarily to the fact that at the current stage of democratic transformation of our country, local self­government is the basis of civil society. Local self-government is one of the most important institutions of a democratic state. Its development is a central scientific problem of municipal law and a "cornerstone” in municipal science for many decades, since its inception. The 1996 Constitution of Ukraine created the legal basis for the development of local self-government as a special type of public power. The article analyzes the constitutional principles that established the status of municipal power, their influence on further legislation and practice of local self­government. The constitutional principles of local self-government are analyzed. The approaches available in modern jurisprudence regarding the definition of the concept of "basics of local self­government” have been considered. Arguments are presented in favor of separating the organizational- legal, territorial, and material-financial bases of the activity of local self-government bodies.

Integer syndrome decoding in the presence of noise

Code-based cryptography received attention after the NIST started the post-quantum cryptography standardization process in 2016. A central NP-hard problem is the binary syndrome decoding problem, on which the security of many code-based cryptosystems lies. The best known methods to solve this problem all stem from the information-set decoding strategy, first introduced by Prange in 1962. A recent line of work considers augmented versions of this strategy, with hints typically provided by side-channel information. In this work, we consider the integer syndrome decoding problem, where the integer syndrome is available but might be noisy. We study how the performance of the decoder is affected by the noise. First we identify the noise model as being close to a centered in zero binomial distribution. Second we model the probability of success of the ISD-score decoder in presence of a binomial noise. Third, we demonstrate that with high probability our algorithm finds the solution as long as the noise parameter d is linear in t (the Hamming weight of the solution) and t is sub-linear in the code-length. We provide experimental results on cryptographic parameters for the BIKE and Classic McEliece cryptosystems, which are both candidates for the fourth round of the NIST standardization process.

Artificial intelligence and robotic surgical education

There are numerous barriers in robotic surgical training, including reliance on observational learning, low-quality feedback, and inconsistent assessment. Artificial intelligence (AI) offers potential solutions to these central problems in robotic surgical education and may allow for more efficient and efficacious training. Three key areas in which AI has particular relevance to robotic surgical education are video labeling, feedback, and assessment. Video labeling refers to the automated designation of prespecified categories to operative videos. Numerous prior studies have applied AI for video labeling, particularly for retrospective educational review after an operation. Video labeling allows learners and their instructors to rapidly identify critical parts of an operative video. We recommend incorporating AI-based video labeling into robotic surgical education where available. AI also offers a mechanism by which reliable feedback can be provided in robotic surgery. Feedback through AI harnesses automated performance metrics (APMs) and natural language processing (NLP) to provide actionable and descriptive plans to learners while reducing faculty assessment burden. We recommend combining supervised AI-generated, APM-based feedback with expert-based feedback to allow surgeons and trainees to reflect on metrics like bimanual dexterity and efficiency. Finally, summative assessment by AI could allow for automated appraisal of surgeons or surgical trainees. However, AI-based assessment remains limited by concerns around bias and opaque processes. Several studies have applied computer vision to compare AI-based assessment with expert-completed rating scales, though such work remains investigational. At this time, we recommend against the use of AI for summative assessment pending additional validity evidence. Overall, AI offers solutions and promising future directions by which to address multiple educational challenges in robotic surgery. Through advances in video labeling, feedback, and assessment, AI has demonstrated ways by which to increase the efficiency and efficacy of robotic surgical education.

The 16th Hilbert Problem for Discontinuous Piecewise Linear Hamiltonian Saddles and Isochronous Centers Separated by a Straight Line

The 16th Hilbert Problem for Discontinuous Piecewise Linear Hamiltonian Saddles and Isochronous Centers Separated by a Straight Line