Search Results (4,248)

We discuss the geometry behind the classical Heisenberg model at the level suitable for third- or fourth-year students who did not have the opportunity to take a course on differential geometry. The arguments presented here rely solely on elementary algebraic concepts such as vectors, dual vectors and tensors, as well as Hamiltonian equations and Poisson brackets in their simplest form. We derive Poisson brackets for classical spins, along with the corresponding equations of motion for the classical Heisenberg model, starting from the two-sphere geometry, thereby demonstrating the relevance of standard canonical procedures in the case of the Heisenberg model. Full article

This article concerns the morpheme a in Czech. It occurs in nominals, conjunctions, and various verbal predicates. In contrast to the common practice of treating such a exponents as independent, accidentally homophonous elements, it is argued that some of these as can be treated as one item. What the syncretic as have in common is pluralizing semantics. Thus, the article proposes that verbal number (specifically, plurality) is related to nominal number and conjunctions. The article addresses the questions of how the multifunctionality of morphemes—such as the Czech a—can be analyzed and which tools of lexical–realizational approaches to morphology are most suitable for the analysis. In addition to the plural interpretation, a brings about changes in the argument structure of verbal predicates and fulfills several functions in the nominal and conjunction domains. The analysis is couched in the Distributed Morphology framework. However, contrary to expectations, the multifunctional a is not treated as an underspecified marker. It is analyzed as an overspecified marker that can realize (i.e., span) several syntactic heads: the pluralization head with the pluralization operator, the voice head, plus some other heads present in verbs and nominals. It is argued that the best option for deriving the multifunctional property of a is to assume the superset principle and pre-linearization spanning. Full article

This paper presents a complete analysis of the Helfrich membrane energy functional in the product space ${\mathbb{H}}^2\times \mathbb{R}$. We address the analytical challenges posed by the ideal boundary of the space by developing a renormalization scheme, allowing us to formulate a well-posed variational problem. We derive the Euler-Lagrange equations for the renormalized functional, characterizing the equilibrium configurations through a coupled system of partial differential equations and a Neumann-type boundary condition. A central result of our work is a rigidity theorem, proven via a Killing field argument, which establishes that any admissible critical surface is necessarily axially symmetric. Finally, we connect this mathematical theory to biophysics by proposing a new variational principle for the Solvent Accessible Surface (SAS) under geometric confinement, demonstrating that our classified surfaces represent the optimal elastic energy shapes for such systems. Full article

Suicidality is a significant and persistent public health concern, and people who are suicidal report negative experiences with clinical services. Peer-based interventions are a rapidly growing component of mental health care and suicide prevention. This scoping review’s aim is to identify, summarise and synthesise the design, features and evidence for peer-led models and interventions for people experiencing emotional distress or suicidal crisis. This study followed the Joanna Briggs Institute scoping review guidelines. Online databases were searched in May 2022 and in October 2024. A total of 59 papers were identified. The scoping review provides an overview of key components of service models and interventions. In general, peer-led programs were widely accepted, with participants reporting positive improvements to mood, social connectedness, communication and coping skills. Despite the importance of training and supervision, a review of training content revealed a discordance between training and peer work principles in some cases. A concentration on facilitation of the service model or intervention rather than on the peer model itself meant there was limited information on the empirical and ethical arguments that supported the model of care. Future research is needed on peer-led models and how involvement and engagement of peers, consumers and carers can positively influence the planning, design, implementation and evaluation of new service models and interventions. Full article

We derive an asymptotic expansion for the tail function of the product of $n(n\in \mathbb{N})$ independent identically distributed Weibull random variables. The coefficients of the expansion are obtained using a recursive formula arising from the Laplace method. The resulting expansion provides explicit higher-order correction terms that significantly improve the accuracy of tail approximations for large arguments. These results are useful for both theoretical analysis and practical applications involving extreme-value behavior of products of random variables. The main result of the paper shows that multiplying Weibull distributions yields so-called Weibull-type distributions. It also shows that under multiplication, the shape parameter of the Weibull distribution decreases. This implies that the product of Weibull distributions becomes more heavily tailed. The asymptotic formula for the tail function of the product of Weibull distributions involves rather complicated coefficients. To compute these coefficients, we provide MATLAB (version 9.13.0, R2022b) code. The application of the main result is illustrated with two particular examples. Full article

Objective (study question): The main purpose of this systematic review was to conduct a qualitative synthesis of quantitative studies among patient experience, patient outcomes, and organisational climate factors. The review sought to answer the following research questions: (i) What are the main directions, dominant methods, and theories on the associations among these concepts? (ii) What theoretical propositions can be made? Data sources/study setting (w/hospital/institution setting anonymised): The study involved a search for literature in PubMed, PsychINFO, Medline, CINAHL, Academic Search Premier, Scopus, and Web of Science between 2007 and 2022 with the guidance of a librarian. The search was limited to English language and to human adult inpatients. Study design: This study primarily employed a systematic review method, following the guidelines in the PRISMA statement. Data collection/extraction methods: Articles were screened and excluded first on title and abstract, and then on fulltexts. Quality assessments were done on remaining articles using the National Institutes of Health (NIH) quality assessment tool for observational, cohort and cross-sectional studies. Data was extracted from articles that met the inclusion criteria and passed the checks. Principal findings: The search identified 11,571 records that were checked for duplications. After removing duplicates and applying the eligibility criteria, a final list of 220 articles were included for the qualitative synthesis. Results showed that the relationships among the concepts were more conclusive and generally positive rather than negative, especially between patient experience and patient outcomes. The review, however, showed areas that required more attention such as an encompassing quality-oriented care climate theory, validation of patient-reported instruments, and longitudinal studies linking subjective patient outcomes to objective patient outcomes. Conclusions: The review shows that conclusions can be drawn on the relationships among the variables, indicating that favourable factors in the hospitals, as perceived by patients, have positive implications for patient experiences and their outcomes. Based on this, an argument for an encompassing framework on quality care climate from the patients’ perspectives was made to enhance understanding of these relationships. Limitations: Among others, this review is limited by the search restriction to quantitative studies or studies that employed mainly quantitative tools to assess associations or changes. Funding: This study received no external funding. Registration: PROSPERO ID- CRD42021291787. Full article

The mulberry-dyke fishpond system represents China’s traditional circular agricultural heritage yet faces challenges of “circularity without economic viability” and preservation under modernization pressures. Taking the Globally Important Agricultural Heritage System site of Digang in Huzhou as a case study, this paper reveals fundamental shifts in its value structure through local research and interviews. Key findings include the following: (1) Significant decline in traditional economic value: Annual income from mulberry-dyke fishpond systems is extremely low, far below the per-mu yield of modern intensive aquaculture in the area. This has led to producer withdrawal and the disintegration of the base-pond structure. (2) Ecological and social values increasingly emerge and partially marketize: The system’s ecological service value is substantial and policy-recognized, with markets responding through a 100% premium on eco-fish prices. Concurrently, heritage-based cultural tourism integration generates significant new value—for instance, Digang village’s 2023 tourism revenue reached 140 million. However, these prominent non-market values still lack stable, adequate realization pathways. The core argument of this study is that the decline in mulberry-dyke fishpond systems stems from an imbalance in value structures rather than the disappearance of value. Their revitalization hinges on institutional innovation that transforms ecological and social value into sustainable market incentives. To this end, this paper proposes a systematic revitalization framework encompassing a concession system (incorporating community interest alignment and risk management clauses), regional brand certification, carbon sink value realization, and mechanisms for deep community participation. This approach aims to provide a Chinese solution for the sustainable development of similar agricultural cultural heritage sites, offering both theoretical insights and practical value. Full article

This paper argues that Westphal’s attempt to overcome onto-theology paradoxically collapses back into it—not through conceptual inconsistency but through a structural reinscription of the very hierarchy he seeks to escape. The argument begins by examining Westphal’s understanding of onto-theology and critically assessing his appropriation of Augustine and Kierkegaard (the latter via Levinas), culminating in his affirmation of “God the Almighty.” This critique is particularly warranted given that Westphal elevates Kierkegaard as the paradigmatic figure for overcoming onto-theology. Subsequently, by drawing on Derrida and Caputo, the study introduces an expanded understanding of onto-theology—encompassing the critique of theocentrism and the obsession with purity—to expose the lacunae in Westphal’s approach. While Westphal successfully avoids the production of a God to whom one cannot pray or offer praise, his project nonetheless remains entrapped within the orbit of onto-theology as theocentrism. The paper concludes by indicating that such attempts to overcome onto-theology risk regressing into a theocentric structure, with significant implications for how religious discourse shapes ethical and political life. Ultimately, it highlights that his hermeneutical approach to God remains firmly theological—indeed, all too theological—and unable to transcend the hermeneutics of religious life. Full article

Central European children’s literature can be read as both archive—recording shifting norms, institutions, and visual regimes—and agent, a medium through which childhood, citizenship, and cultural memory are made legible. This conceptual article proposes an edition-sensitive framework for analysing texts, images, and paratexts across Central Europe (1860–2025), with particular attention to institutional mediation. Rather than offering a comprehensive dataset or causal claims about reception, it synthesises research in childhood history, book and media history, memory studies, and translation and circulation studies to advance three arguments. First, children’s books are institutionally framed artefacts: paratexts and material features (series branding, curricular endorsements, library markings, pricing cues, regulatory traces) can be read as historically interpretable speech acts of legitimation. Second, shifts in visual and material regimes should be analysed as changing conditions of legibility—expectations of clarity, affect, and authority—rather than as mere stylistic evolution. Third, translation and circulation function as infrastructures that reorganise repertoires and interpretive horizons, complicating nation-centred narratives without exhaustive market mapping. The article concludes by stating methodological limits (catalogue gaps, survival bias, uneven metadata) and outlining a transferable agenda for paratext-centred documentation and edition-sensitive reading. Full article

Background/Objectives: The scientific community is still divided between supporters of the implantation theory and researchers who advocate the theory of coelomic metaplasia/embryonic cell remnants to explain the initiation of endometriosis. A frequently cited argument in favor of the coelomic metaplasia/embryonic cell remnants theory is the occurrence of endometriosis in the Mayer-Rokitansky-Kuster-Hauser syndrome, since retrograde menstruation is not possible without endometrium. However, nearly all women with uterovaginal agenesis have uterine remnants that harbour islets of endometrium. Methods: To verify the validity of the coelomic metaplasia/embryonic cell rests theory, we analysed all reports of endometriosis in patients with Mayer-Rokitansky-Kuster-Hauser syndrome without endometrium, published between 1980 and 2025. Three criteria had to be met in order to clearly demonstrate the absence of endometrium and the presence of endometriosis: (i) preoperative imaging, (ii) surgical visualization, and (iii) histological examination. Results: None of the nine reports fully met all three criteria, and the presence of endometrium could never be ruled out. In addition, we used ten characteristics to assess the ‘goodness’ of a theory: testability, logical coherence, conceptual clarity and comprehensibility, external consistency, empirical validity, predictive power, parsimony, broad applicability, practical utility, and heuristic value. Conclusions: Overall, the implantation theory appears to fully satisfy all criteria to explain the onset of endometriosis in Mayer-Rokitansky-Kuster-Hauser syndrome. In contrast, the coelomic metaplasia/embryonic cell rests theory satisfies eight criteria only partly and does not satisfy two of them. Therefore, the null hypothesis that endometriosis can be present in the absence of endometrium in patients with utero-vaginal agenesis can be reasonably rejected. Full article

Environmental sustainability (ES) has increasingly become a core focus of the International Olympic Committee (IOC) due to institutional pressures as well as the threat of climate change. Since the IOC continues to urge candidature cities to underscore ES in the bidding and planning process by asking more elaborate questions in the Candidature Questionnaire, it remains unclear how winning cities have adapted their bids to demonstrate their accountability to win the rights to host an ES Games. One approach to better understanding the discourse candidature cities use in their ES plans is to study how bid committees employ Aristotle’s rhetorical appeals—ethos (credibility), pathos (emotion), and logos (logic). To do so, this qualitative case study analyzed winning candidature files of the Summer and Winter Olympic Games (N = 16) from 1992 to present day. The results revealed one distinct rhetorical appeal, ethos, emerged more than the others that underscored the value of highlighting credibility in ES contexts. One of the most interesting findings of the study is that ethos-based arguments depend greatly on existing governance infrastructures, policies, certifications, and previous experience, external to the IOC governance process. This is a significant finding because it shows the paradox of embedded agency, while also highlighting how establishing credibility is more important to cities than merely promising results. Full article

Critical thinking (CT) is increasingly recognized as a transversal competence within STEM education, yet it is often addressed implicitly in preservice teacher training. This study analyzes the development of critical thinking in 130 Preservice Early Childhood Education Teachers (PECETs) who, during the 2024–2025 academic year, participated in a training programme designed from a STEM perspective and grounded in scientific inquiry. A mixed-methods approach was used to examine the teaching unit elaborated by PECETs with a rubric that assessed stages of inquiry, as well as to analyze their final reports for evidence of connections between CT and STEM. The findings revealed strong scientific thinking but only superficial links to STEM and CT suggesting progress in participants’ scientific reasoning and analytical and reflective competence. However, evidence of explicit STEM integration and CT justification remained limited. These results confirm the formative potential of inquiry-based STEM education for supporting CT development in early childhood preservice teacher education, while highlighting the need for more explicit scaffolding of inquiry phases, structured reflection opportunities, and collaborative argumentation tasks to strengthen conceptual integration and deepen critical engagement with scientific evidence. Full article

In light of the current eco-social crisis, environmental education must adopt a transformative, critical literacy-based approach grounded in scientific practices to prepare students to address socioenvironmental issues from a systemic perspective. This study, which was conducted with 4th and 6th-grade primary school students (aged 9–12), presents the results of an activity based on a socioscientific issue about the presence of pharmaceuticals in surface water. The aim is to evaluate students’ performance in argumentation, their use of and understanding of the materials from which they extract evidence, and the solutions they propose. To this end, the content (written reports) and discourse (group discussions) were analyzed, and different statistical tests were carried out to compare individual and group performance, as well as performance among educational levels. The results show students in both years tend to perform at a low-to-medium level, with higher performance in 6th grade, but there are no significant differences in most areas. They also use materials in different semiotic modalities; similarly, they experience more difficulty with maps and graphs than with texts and videos. Additionally, they propose solutions from various perspectives. Overall, this approach contributes to the development of scientific reasoning in primary school students and should therefore be incorporated into their classroom culture. Full article

This paper addresses the question of how many autonomous aerial vehicles (UAVs or drones) can safely operate within a bounded three-dimensional airspace. First, we derive the absolute mathematical limits on drone density using geometric arguments from sphere packing and covering theory. Then, we verify these limits empirically by simulating a swarm controlled via model predictive control. We incrementally increase the number of drones until motion becomes impossible. Each drone is modeled as a double-integrator system with a bounded speed and acceleration and is surrounded by a radius spherical safety zone $r>0$. The drones are controlled via model predictive control with hard separation constraints. We formalize complete blockage as the loss of any feasible non-trivial trajectory set, either due to geometric crowding or dynamic limitations. Using tools from discrete geometry, we establish absolute upper bounds on a safe population via sphere-packing results and sufficient conditions for total immobilization via sphere-covering arguments. We extend these static bounds by incorporating dynamics through stopping-distance analysis, leading to an inflated exclusion radius that captures the effect of finite control authority. In addition, we prove min-cut style flow-capacity bounds that limit feasible throughput across bottlenecks and derive horizon-dependent conflict-graph conditions that capture MPC infeasibility at high densities. These results provide a rigorous theoretical framework for determining the transition from feasible multi-drone operation to inevitable gridlock, offering explicit quantitative thresholds that can inform airspace design, drone density regulation, and the tuning of predictive controllers. We evaluate our theoretical findings with a simulation environment. Full article

In this study, we developed an SIR-like mathematical model of disease transmission dynamics. Hantavirus is a neglected tropical disease, and this paper presents a mathematical model of hantavirus transmission among rodents and its effect on the number of hantavirus-infected humans. We review an existing SIR-SIR model of hantavirus transmission and analyze it in a standard mathematical epidemiology framework. The original SIR-SIR model is summarized, with emphasis on its structural assumptions, epidemiological interpretation, and analytical results, including the derivation of the basic reproduction number and the characterization of the stability of the disease-free and endemic equilibria. A critical evaluation of the original SIR-SIR model highlights several biological limitations of the baseline model, notably, the unrealistic assumption of homogeneous transmission and the absence of ecological seasonality. To address these gaps, an improved model incorporating periodic forcing in rodent recruitment and disease transmission is proposed. The use of sine and cosine functions introduces a biologically motivated phase shift between rodent recruitment and transmission, reflecting the fact that birth pulses and peak contact rates rarely occur simultaneously in natural rodent populations. The reproduction number for the extended system is constructed using a Floquet-style argument for DFE stability. A theorem connecting the stability of the DFE with the seasonal component is presented, resembling the well-known rule for non-seasonal hantavirus transmission but with more realistic assumptions. Numerical simulations demonstrate that seasonal variation can generate oscillatory outbreak patterns that more closely reflect empirical rodent population dynamics and human risk profiles. Overall, the results underscore the importance of ecological realism in zoonotic disease modeling and provide a foundation for more accurate prediction and control of the disease, especially in NTD elimination programs. Full article