Search Results (85)

A novel unified progressive hybrid censoring is introduced to combine both progressive and hybrid censoring plans to allow flexible test termination either after a prespecified number of failures or at a fixed time. This work develops both frequentist and Bayesian inferential procedures for estimating the parameters, reliability, and hazard rates of the inverted Nadarajah–Haghighi lifespan model when a sample is produced from such a censoring plan. Maximum likelihood estimators are obtained through the Newton–Raphson iterative technique. The delta method, based on the Fisher information matrix, is utilized to build the asymptotic confidence intervals for each unknown quantity. In the Bayesian methodology, Markov chain Monte Carlo techniques with independent gamma priors are implemented to generate posterior summaries and credible intervals, addressing computational intractability through the Metropolis—Hastings algorithm. Extensive Monte Carlo simulations compare the efficiency and utility of frequentist and Bayesian estimates across multiple censoring designs, highlighting the superiority of Bayesian inference using informative prior information. Two real-world applications utilizing rare minerals from gold and diamond durability studies are examined to demonstrate the adaptability of the proposed estimators to the analysis of rare events in precious materials science. By applying four different optimality criteria to multiple competing plans, an analysis of various progressive censoring strategies that yield the best performance is conducted. The proposed censoring framework is effectively applied to real-world datasets involving diamonds and gold, demonstrating its practical utility in modeling the reliability and failure behavior of rare and high-value minerals. Full article

Background/Objective: South Korea continues to have the highest suicide rate among the Organization for Economic Co-operation and Development (OECD) countries, with a growing number of emergency department (ED) admissions related to self-harm and suicide attempts. However, trauma-focused analyses that integrate psychiatric profiles and suicide mechanisms remain limited, hindering effective clinical care and preventive strategies. Methods: This retrospective study analyzed trauma patients who presented to the ED of Wonju Severance Christian Hospital following suicide attempts between October 2015 and December 2023. Of 305 self-harm cases, 208 survivors who underwent psychiatric evaluation were included. The variables analyzed included the mechanism, site, and severity of injury (ISS and AIS); psychiatric diagnosis and prior psychiatric history; repeated suicide attempts; alcohol use; physical pain; interpersonal conflict; and economic vulnerability. Chi-square, Fisher’s exact, and Kruskal–Wallis’ tests were used for statistical comparisons. Results: Stabbing/cutting (56.7%) and falling (35.6%) were the most common attempts. Mood disorders were the predominant psychiatric diagnosis (63.9%), followed by adjustment disorders (26.0%), alcohol use (25.5%), and psychotic disorders (22.1%). Among the fall-related cases, patients were typically younger and predominantly women. The median ISS was highest in fall-related cases (17) compared with stabbing/cutting (4), with 25.96% of patients with an ISS ≥16, indicating severe trauma. A psychiatric history was associated with a higher incidence of falls (44.3%), and previous suicide attempts correlated with the use of high-lethality attempts. Severe physical pain was linked to stabbing/cutting in 10 of 11 cases. Interpersonal conflict was more frequently associated with stabbing/cutting (59.6%) than with falls (31.9%). No significant association was found between alcohol use and the method of suicide attempt. Conclusions: The suicide mechanisms in patients with trauma are closely associated with psychiatric and psychosocial factors. Stabbing/cutting is often impulsive and driven by interpersonal conflict or alcohol use, while falling is more frequent in patients with psychiatric histories of repeated attempts. These findings emphasize the importance of mechanism-informed psychiatric evaluations and trauma protocols. Regionally adapted, interdisciplinary approaches and early psychiatric intervention are crucial for effective post-attempt management and suicide prevention. Full article

Background: adenoviruses (AdVs) are DNA viruses that typically cause mild infections in immunocompetent children, and typically involve the respiratory and gastrointestinal tract. Adenoviral pharyngitis is a common paediatric illness, particularly in children under 4 years old. The aim of our 7-year retrospective study, conducted at a tertiary care paediatric emergency department (ED), was to describe the clinical and laboratory characteristics and management of patients with pharyngeal AdV infections. Specifically, we examined how the management of patients with adenoviral pharyngitis has evolved following the introduction of a rapid antigen nasopharyngeal swab test for AdVs, which has been performed directly in the ED since 2023. Methods: in this single-centre retrospective observational study, the demographic and clinical information for children discharged from the ED who had been diagnosed with a pharyngeal AdV infection between 1 January 2017 and 31 December 2023 were retrospectively reviewed. Moreover, we compared data before and after the introduction of rapid AdV antigenic swabs, which have been directly performed in the ED since the beginning of 2023. Statistical analysis was undertaken using the Student’s t-test and Pearson and Fisher’s exact test, as appropriate. Significance was set at p-value < 0.05. Results: during the study period, 172 children were diagnosed with adenoviral pharyngitis based on a positive swab. All patients were febrile, with a median duration of fever of 4 days. Blood tests were requested for 84.9% of patients at admission, resulting in a mean WBC count of 13,250/mmc and a mean CRP of 70.6 mg/L. The highest CRP median values were found on the third day of fever. Out of 383 swabs performed during 2017–2022, 13.6% were positive vs a 32% positive rate for the 372 swabs performed in 2023. The mean duration of observation in the ED before 2023 was 31.4 h vs. 10.4 h in 2023. Similarly, 9% of patients with adenoviral pharyngitis were admitted to a paediatric ward before 2023 and only 0.8% in 2023. Conclusions: the primary reason for ED admission in cases of adenoviral pharyngitis is fever lasting several days due to hyperinflammation. Differential diagnosis with bacterial infection is essential to limit the number of hospitalisations and inappropriate antibiotic therapy. The introduction of the rapid antigen nasopharyngeal swab has simplified the diagnosis of adenoviral pharyngitis, enabling timely and accurate differentiation from bacterial causes. Full article

This research paper focuses on dimensionality reduction, which is a major subproblem in any data processing operation. Dimensionality reduction based on principal components is the most used methodology. Our paper examines three heuristics, namely Kaiser’s rule, the broken stick, and the conditional number rule, for selecting informative principal components when using principal component analysis to reduce high-dimensional data to lower dimensions. This study uses 22 classification datasets and three classifiers, namely Fisher’s discriminant classifier, logistic regression, and K nearest neighbors, to test the effectiveness of the three heuristics. The results show that there is no universal answer to the best intrinsic dimension, but the conditional number heuristic performs better, on average. This means that the conditional number heuristic is the best candidate for automatic data pre-processing. Full article

We present a Fisher information matrix study of the parameter estimation precision achievable by a class of future space-based, “mid-band”, gravitational wave interferometers observing monochromatic signals. The mid-band is the frequency region between that accessible by the Laser Interferometer Space Antenna (LISA) and ground-based interferometers. We analyze monochromatic signals observed by the TianQin mission, gLISA (a LISA-like interferometer in a geosynchronous orbit) and a descoped gLISA mission, gLISA_d, characterized by an acceleration noise level that is three orders of magnitude worse than that of gLISA. We find that all three missions achieve their best angular source reconstruction precision in the higher part of their accessible frequency band, with an error box better than ${10}^{-10}$ sr in the frequency band [${10}^{-1},10$] Hz when observing a monochromatic gravitational wave signal of amplitude $h_0={10}^{-21}$ that is incoming from a given direction. In terms of their reconstructed frequencies and amplitudes, TianQin achieves its best precision values in both quantities in the frequency band [${10}^{-2},4\times {10}^{-1}$] Hz, with a frequency precision ${\sigma }_{f_{gw}}=2\times {10}^{-11}$ Hz and an amplitude precision ${\sigma }_{h_0}=2\times {10}^{-24}$. gLISA matches these precisions in a frequency band slightly higher than that of TianQin, [$3\times {10}^{-2},1$] Hz, as a consequence of its smaller arm length. gLISA_d, on the other hand, matches the performance of gLISA only over the narrower frequency region, [$7\times {10}^{-1},1$] Hz, as a consequence of its higher acceleration noise at lower frequencies. The angular, frequency, and amplitude precisions as functions of the source sky location are then derived by assuming an average signal-to-noise ratio of 10 at a selected number of gravitational wave frequencies covering the operational bandwidth of TianQin and gLISA. Similar precision functions are then derived for gLISA_d by using the amplitudes resulting in the gLISA average SNR being equal to 10 at the selected frequencies. We find that, for any given source location, all three missions display a marked precision improvement in the three reconstructed parameters at higher gravitational wave frequencies. Full article

Objectives: This study aimed to evaluate the incidence of adverse reactions to the COVID-19 vaccine among pregnant and breastfeeding women and identify associated demographic and clinical factors. Methods: A cross-sectional study was conducted at a hospital in Hanoi, Vietnam, from November 2021 to March 2022. A total of 1204 participants, including 991 pregnant women beyond 13 weeks of gestation and 213 breastfeeding women, were recruited through convenience sampling. Data were collected using a self-administered questionnaire designed to capture demographic information and adverse reactions occurring within seven to 28 days post-vaccination. Statistical analyses, including chi-square tests, Fisher’s exact tests, and logistic regression, were performed using Stata 16.0, with the significance set at p < 0.05. Results: The most common adverse reactions were localized pain at the injection site (26.2%), dizziness and fatigue (19.2%), and fever below 39 °C (29.1%). Severe adverse reactions, such as a tight throat, coma, and premature birth, were rare. A multivariate analysis identified the significant factors associated with the adverse reactions, including age (aOR = 2.04 for participants aged 36–40 years), occupation (lower odds for farmers and business professionals), urban residency (aOR = 0.64), and a history of allergies (aOR = 1.59). Education level, number of children, and gestational age were not significantly associated with adverse events. Conclusions: The findings support the safety of the COVID-19 vaccine in pregnant and breastfeeding women, with most of the adverse reactions being mild and self-limiting. Full article

Background: Medication-related osteonecrosis of the jaw (MRONJ) is a rare but serious adverse event. Herein, we conducted a quantitative structure–activity relationship analysis using the U.S. Food and Drug Administration Adverse Drug Reaction Database System (FAERS) and machine learning to construct a drug prediction model for MRONJ induction based solely on chemical structure information. Methods: A total of 4815 drugs from FAERS were evaluated, including 70 and 139 MRONJ-positive and MRONJ-negative drugs, respectively, identified based on reporting odds ratios, Fisher’s exact tests, and ≥100 total adverse event reports. Then, we calculated 326 chemical structure descriptors for each drug and compared three supervised learning algorithms (random forest, gradient boosting, and artificial neural networks). We also compared the number of chemical structure descriptors (5, 6, 7, 8, 9, 10, 20, and 30 descriptors). Results: We indicated that the MRONJ prediction model using an artificial neural network algorithm and eight descriptors achieved the highest validation receiver operating characteristic curve value of 0.778. Notably, the total polar surface area (ASA_P) was among the top-ranking descriptors, and MRONJ-positive drugs such as bisphosphonates and anticancer drugs showed high values. Our final model demonstrated a balanced accuracy of 0.693 and a specificity of 0.852. Conclusions: In this study, our MRONJ-inducing drug prediction model identified drugs with polar surface area properties as potential causes of MRONJ. This study demonstrates a promising approach for predicting MRONJ risk, which could enhance drug safety assessment and streamline drug screening in clinical and preclinical settings. Full article

We propose a scheme to enhance the range and precision of ultra-low temperature measurements by employing a probe qubit coupled to a chain of ancilla qubits. Specifically, we analyze a qubit chain governed by Heisenberg $XX$ and Dzyaloshinskii–Moriya (DM) interactions. The precision limits of temperature measurements are characterized by evaluating quantum Fisher information (QFI). Our findings demonstrate that the achievable precision bounds, as well as the number of peaks in the QFI as a function of temperature, can be controlled by adjusting the number of ancilla qubits and the system’s model parameters. These results are interpreted in terms of the influence of energy transitions on the range and the number of QFI peaks as a function of temperature. This study highlights the potential of the probe qubit–ancilla chain system as a powerful and precise tool for quantum thermometry in the ultra-low temperature regime. Full article

In this article, we present a model for analyzing the co-occurrence count data derived from practical fields such as user–item or item–item data from online shopping platforms and co-occurring word–word pairs in sequences of texts. Such data contain important information for developing recommender systems or studying the relevance of items or words from non-numerical sources. Different from traditional regression models, there are no observations for covariates. Additionally, the co-occurrence matrix is typically of such high dimension that it does not fit into a computer’s memory for modeling. We extract numerical data by defining windows of co-occurrence using weighted counts on the continuous scale. Positive probability mass is allowed for zero observations. We present the Shared Parameter Alternating Tweedie (SA-Tweedie) model and an algorithm to estimate the parameters. We introduce a learning rate adjustment used along with the Fisher scoring method in the inner loop to help the algorithm stay on track with optimizing direction. Gradient descent with the Adam update was also considered as an alternative method for the estimation. Simulation studies showed that our algorithm with Fisher scoring and learning rate adjustment outperforms the other two methods. We applied SA-Tweedie to English-language Wikipedia dump data to obtain dense vector representations for WordPiece tokens. The vector representation embeddings were then used in an application of the Named Entity Recognition (NER) task. The SA-Tweedie embeddings significantly outperform GloVe, random, and BERT embeddings in the NER task. A notable strength of the SA-Tweedie embedding is that the number of parameters and training cost for SA-Tweedie are only a tiny fraction of those for BERT. Full article

I study a lattice with periodic boundary conditions using a non-local master equation that evolves over time. I investigate different system regimes using classical theories like Fisher information, Shannon entropy, complexity, and the Cramér–Rao bound. To simulate spatial continuity, I employ a large number of sites in the ring and compare the results with continuous spatial systems like the Telegrapher’s equations. The Fisher information revealed a power-law decay of $t^{-\nu }$, with $\nu =2$ for short times and $\nu =1$ for long times, across all jump models. Similar power-law trends were also observed for complexity and the Fisher information related to Shannon entropy over time. Furthermore, I analyze toy models with only two ring sites to understand the behavior of the Fisher information and Shannon entropy. As expected, a ring with a small number of sites quickly converges to a uniform distribution for long times. I also examine the Shannon entropy for short and long times. Full article

The mapped Fourier grid method (mapped-FGM) is a simple and efficient discrete variable representation (DVR) numerical technique for solving atomic radial Schrödinger differential equations. It is set up on equidistant grid points, and the mapping, a suitable coordinate transformation to the radial variable, deals with the potential energy peculiarities that are incompatible with constant step grids. For a given constrained number of grid points, classical phase space and semiclassical arguments help in selecting the mapping function and the maximum radial extension, while the energy does not generally exhibit a variational extremization trend. In this work, optimal computational parameters and mapping quality are alternatively assessed using the extremization of (coordinate and momentum) Fisher information. A benchmark system (hydrogen atom) is employed, where energy eigenvalues and Fisher information are traced in a standard convergence procedure. High-precision energy eigenvalues exhibit a correlation with the extrema of Fisher information measures. Highly efficient mapping schemes (sometimes classically counterintuitive) also stand out with these measures. Same trends are evidenced in the solution of Dalgarno–Lewis equations, i.e., inhomogeneous counterparts of the radial Schrödinger equation occurring in perturbation theory. A detailed analysis of the results, implications on more complex single valence electron Hamiltonians, and future extensions are also included. Full article

Objective: There is a demand to make hospital management information beyond basic key performance indicators (KPIs) accessible for clinicians. Methods: We developed an interactive application (IAPP) in R Shiny to visualize such information. We provided the IAPP source code online. As a use case, we recorded basic KPIs (numbers of patients (NPs), reimbursed valuation ratios (RVRs), mean length of stay (LOS)), main diagnoses (MDGNs), main procedures (MPRCs), and catchment area (CA) by district from April 2022 to March 2024 at the index department in central Germany, where a neurotrauma and spinal surgery service was resumed on 1 April 2022. Case mix indexes (CMIs) were calculated. We retrieved information about online-reported patient satisfaction (ORPS) from an online physician rating platform between January 2022 and March 2024. Information on longitudes and latitudes of the index department and neighbouring hospitals was collected. We calculated car travelling isochrones (CTIs) of the hospitals as a proxy variable for accessibility. Chi-square and Fisher’s exact served as statistical tests. Results: During the observation period, the monthly NPs increased from 26 to 43, the RVR showed a 3.96-fold increase, the CMI showed a 2.41-fold increase, and the LOS reached a steady state in the 2nd year after service resumption. CA (p = 0.03), MDGNs, and MPRCs diversified. ORPS trended towards better overall evaluation after service resumption (p = 0.09). CTI mapping identified a unique market position of the index department. Conclusions: The IAPP makes extended hospital management data accessible to clinicians, can inform other stakeholders in healthcare, and can be tailored to local conditions. Full article

The classical tests for combining p-values use suitable statistics $T(P_1,\dots ,P_n)$, which are based on the assumption that the observed p-values are genuine, i.e., under null hypotheses, are observations from independent and identically distributed $\mathrm{Uniform}(0,1)$ random variables $P_1,\dots ,P_n$. However, the phenomenon known as publication bias, which generally results from the publication of studies that reject null hypotheses of no effect or no difference, can tempt researchers to replicate their experiments, generally no more than once, with the aim of obtaining “better” p-values and reporting the smallest of the two observed p-values, to increase the chances of their work being published. However, when such “fake p-values” exist, they tamper with the statistic $T(P_1,\dots ,P_n)$ because they are observations from a $\mathrm{Beta}(1,2)$ distribution. If present, the right model for the random variables $P_k$ is described as a tilted Uniform distribution, also called a Mendel distribution, since it was underlying Fisher’s critique of Mendel’s work. Therefore, methods for combining genuine p-values are reviewed, and it is shown how quantiles of classical combining test statistics, allowing a small number of fake p-values, can be used to make an informed decision when jointly combining fake (from Two P) and genuine (from not Two P) p-values. Full article

The detection of limit cycles of differential equations poses a challenge due to the type of the nonlinear system, the regime of interest, and the broader context of applicable models. Consequently, attempts to solve Hilbert’s sixteenth problem on the maximum number of limit cycles of polynomial differential equations have been uniformly unsuccessful due to failing results and their lack of consistency. Here, the answer to this problem is finally obtained through information geometry, in which the Riemannian metrical structure of the parameter space of differential equations is investigated with the aid of the Fisher information metric and its scalar curvature R. We find that the total number of divergences of $\left|\mathrm{R}\right|$ to infinity provides the maximum number of limit cycles of differential equations. Additionally, we demonstrate that real polynomial systems of degree $n\ge 2$ have the maximum number of $2(n-1)\left(4\right(n-1)-2)$ limit cycles. The research findings highlight the effectiveness of geometric methods in analyzing complex systems and offer valuable insights across information theory, applied mathematics, and nonlinear dynamics. These insights may pave the way for advancements in differential equations, presenting exciting opportunities for future developments. Full article

Background: Compared to the general population, individuals with special needs tend to have worse oral health, potentially diminishing their quality of life. This study aimed to evaluate the perception of parents and caregivers regarding the effect of oral health on the quality of life of individuals with special needs who received dental treatment under general anaesthesia, as well as the impact on their and their families’ quality of life. Materials and methods: This cross-sectional study involved participants with special needs who had undergone a dental treatment under general anaesthesia. Before the intervention, an oral examination was conducted to count the number of teeth affected by caries. Parents or caregivers filled out a specially designed questionnaire that included sociodemographic information, details about the children’s oral hygiene and dietary habits, and questionnaires on the impact of their child’s oral health on their quality of life (P-CPQ) and the influence of the oral health of children with psychophysical difficulties on the family (FIS). The data collected were analysed both descriptively and using the chi-square test, Fisher’s exact test, Kruskal–Wallis test, and Spearman’s correlation analysis. The level of significance was set at p ≤ 0.05. Results: This study involved 42 children (24 females and 18 males) with an average age of 21.14 ± 8.34 years. The average number of carious teeth per participant was 9.74 ± 5.63. About 66% of respondents reported that their children performed oral hygiene with their help, while 9.5% of them did not do so at all. Individuals with a higher number of caries had statistically significantly higher scores on the emotional well-being (p = 0.004) and social well-being (p = 0.033) subscales of P-CPQ, as well as on the parental emotions subscale of FIS (p = 0.020). Also, there was a difference in the number of carious teeth in participants due to unhealthy habits (drinking sweetened beverages, p = 0.030) and due to comforting with food (p = 0.004). Conclusion: The increase in the number of carious teeth in individuals with special needs has been associated with the quality of life of their families. To address this, it is crucial to promote the prevention of oral health issues by educating individuals with special needs and their caregivers on proper oral hygiene techniques and diets tailored to their specific requirements. Full article