Eric D.

The development of a zygote into a functional organism requires that this single progenitor cell gives rise to numerous distinct cell types. Attemp...

This research communication presents an analysis of dynamic supply chains (DSCs). The main goal of model-based cybertronics is to approximate, via a mathematical model from a dynamical system, the dynamics and behavior of dynamic supply chains. This considers that is at the operational level, where automation and control theory approaches take an insight —in this case, via Lyapunov stability—as a way to extend the use of mechatronic systems. Three case studies are presented: Firstly, the mathematical modeling and stability analysis of the ball-and-beam problem, as an approximation of a two echelon supply chain. Secondly, the mathematical modeling and stability analysis of a cold chain with temperature monitoring, and its relationship to inventory levels, are presented. From a theoretical perspective, applying model-based cybertronics in DSCs has direct practical implications: it improves operational control, enhances decision-making, and optimizes inventory management, particularly in cold chains. By treating high-volume supply chains as dynamical systems, managers can anticipate fluctuations and quantify efficiency. Finally, Lyapunov stability analysis ensures that models reliably reflect real-world behavior, enabling automation and predictable performance at an operational level in DSCs.

Background: Echocardiography is a non-invasive test that is readily used to detect pulmonary hypertension associated with bronchopulmonary dysplasia (BPD-PH) and right ventricular failure (RVF). However, the most feasible, reproducible and accurate parameters to measure and use for guidance in addressing patient care have not been established and may differ between subspecialties. Methods: We surveyed members of the BPD Collaborative to determine how different care providers clinically evaluate infants for BPD-PH and RVF. Perceived challenges and obstacles that limit the utility of echocardiography are also reported. Results: Of the 108 survey respondents from ~45 centers, 55.6% were neonatologists, 18.5% were pediatric pulmonologists or pediatric intensive care physicians, 15.7% were pediatric cardiologists or pulmonary hypertension specialists, and 10.2% were other providers. Responses revealed discrepancies between specialists concerning the use of standard echocardiographic protocols and parameters that can be measured serially with relative ease, metrics that should be used to best define and distinguish the severity of BPD-PH or RVF, and parameter values that should be used to determine whether changes in PH-targeted medical therapies, hemodynamic or respiratory support are needed. Free text responses identified patient-, protocol-, cardiology-, technician-, and BPD-PH definition-related obstacles that may limit the reliable utility of echocardiography. Conclusions: Although most providers agree that echocardiography is feasible and of value, variability exists between subspecialists and centers, suggesting the need for improved standardization of imaging protocols and BPD-PH definition, consistent test interpretation, and effective communication of results to improve the reproducibility and accuracy of echocardiography in infants with BPD.

Autism spectrum disorders (ASDs) are characterized by a deficit in social communication, pathologic repetitive behaviors, restricted interests, and...

Gene expression is a stochastic, or “noisy,” process. This noise comes about in two ways. The inherent stochasticity of biochemical processes such ...

Purpose To evaluate emergency CT interpretation demand during major sporting events, characterize surge-related backlog and turnaround time, and estimate how threshold-based teleradiology support could affect queue performance during short event-related imaging boluses. Methods We developed a Monte Carlo discrete-event simulation in Python to model an 8-h emergency radiology shift with baseline CT demand and a 2-h event-related surge. CT arrivals followed a Poisson process. Local and teleradiology radiologists were modeled as parallel servers with stochastic interpretation times. Two scenarios were compared across 500 Monte Carlo iterations: local radiologists only and local radiologists supplemented by a rapid-response teleradiology team activated when the unread CT backlog reached 10 cases. Primary outcomes included mean turnaround time, 90th percentile turnaround time, unread queue wait time, maximum unread backlog, number of cases delayed for more than 60 min, and time above the activation threshold. Results The model generated a mean of 132.7 CT examinations per shift in both scenarios. Local-only coverage resulted in a mean turnaround time of 48.7 min and a 90th percentile turnaround time of 89.6 min. With teleradiology support, the mean turnaround time decreased to 18.0 min, and the 90th percentile to 37.3 min. Mean maximum unread backlog decreased from 27.7 to 16.2 cases, and the mean number of cases delayed longer than 60 min decreased from 47.4 to 2.0. Sensitivity analysis showed that saturation risk increased sharply when surge arrivals rose and local staffing remained limited. Conclusion Discrete-event simulation can help emergency radiology departments estimate when CT interpretation workflows may become saturated during major sporting events. In this model, threshold-based teleradiology reduced backlog and turnaround time but functioned as a surge buffer rather than a substitute for adequate local staffing and predefined escalation pathways.

Whether Archean arc-like volcanism reflects subduction remains debated. We present high-resolution geochemical data from a well-preserved 3.13-3.10

Vegetation surveys provide key information for evaluating functions within and across estuaries. However, survey methods and analyses are often highly variable, site-specific, and driven by monitoring program goals and objectives, making regional comparisons that include multiple programs difficult. This study compared multiple transect- and quadrat-based vegetation monitoring methods within eight southern California estuaries to assess variability and comparability among methods within programs and to provide recommendations for the development of regional and statewide coastal wetland monitoring programs. Using data from established monitoring programs with distinct, non-overlapping goals, vegetation percent cover, species richness, and community composition across five commonly used methods (line intercept, point contact, swath intercept, standard (visually assessed) quadrat, and laser quadrat) were compared. Of the seven vegetation cover comparisons made within programs (n = 2) and methods (n = 5), estimates did not vary by more than 7% on average, with the exception (12%) of the one newly restored and sparsely vegetated wetland included in the analysis. Similarly, plant community composition was not significantly different between methods. Whether the methods were comparable depended on three main factors: (1) method category (transect vs. quadrat), (2) the total amount of cover (high vs. low), and (3) the type of vegetation metrics (percent cover, species richness, and community composition). We also examined how survey decisions (e.g., bounding, plant state, nomenclature, binning) affected vegetation cover estimates within each monitoring program. Surprisingly, standardization across survey decisions was not key to the ability to compare within site estimates. However, it was critical for surveyors to first collect bounded vegetated and non-vegetated cover estimates (i.e., whether overall cover estimates can exceed 100%). When survey designs were similar (e.g., all transect-based and bounded), the data required less manipulation when combining and therefore had higher quality assurance than when survey designs varied (e.g. transect versus quadrat or bounded versus unbounded or combination). Review of method comparisons and survey decisions is reflected in a conceptual framework and led to six conclusions and recommendations for standardized, site-intensive vegetation monitoring that can inform broader recommendations for regional coastal wetland monitoring programs.