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Search Results (138)

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21 pages, 2229 KiB  
Article
Multi-Server Two-Way Communication Retrial Queue Subject to Disaster and Synchronous Working Vacation
by Tzu-Hsin Liu, He-Yao Hsu and Fu-Min Chang
Algorithms 2025, 18(1), 24; https://doi.org/10.3390/a18010024 - 5 Jan 2025
Viewed by 297
Abstract
This research analyzes a multi-server retrial queue with two types of calls: working vacation and working breakdown. The incoming call may enter the retrial queue and attempt to seize a server after a random delay if all the servers are unavailable upon arrival. [...] Read more.
This research analyzes a multi-server retrial queue with two types of calls: working vacation and working breakdown. The incoming call may enter the retrial queue and attempt to seize a server after a random delay if all the servers are unavailable upon arrival. In its idle time, the server makes outgoing calls. All the servers take a synchronous working vacation when the system empties after regular service. The system may fail at any time due to disasters, forcing all the calls within the service area to leave the system and causing all the main servers to fail. When the main servers fail, the repair process begins immediately. The standby servers serve arriving customers at a lower level of service during the working breakdown or working vacation. For this model, we derive an explicit expression for the stationary distribution with the help of the quasi-birth-and-death process and the matrix geometric method. Further, the formulas of various system performance indices are developed. An application example is given and several numerical experiments are performed to verify the analytical results. We also perform the comparative analysis of retrial queues with/without two-way communication and two-way communication retrial queues with/without disasters. The results reveal that the proper consideration of outgoing calls to the server can reduce the average time spent in the buffer. Furthermore, a more reliable server reduces the server idle rate. Full article
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Figure 1

Figure 1
<p><math display="inline"><semantics> <mrow> <mover accent="true"> <mrow> <mi>O</mi> </mrow> <mo>¯</mo> </mover> </mrow> </semantics></math> for different values of c by varying (<b>a</b>) <math display="inline"><semantics> <mrow> <mi>λ</mi> </mrow> </semantics></math>, (<b>b</b>) <math display="inline"><semantics> <mrow> <mi>α</mi> </mrow> </semantics></math>, (<b>c</b>) <math display="inline"><semantics> <mrow> <msub> <mrow> <mi>μ</mi> </mrow> <mrow> <mn>1</mn> </mrow> </msub> </mrow> </semantics></math>, (<b>d</b>) <math display="inline"><semantics> <mrow> <msub> <mrow> <mi>μ</mi> </mrow> <mrow> <mi>w</mi> </mrow> </msub> </mrow> </semantics></math>, (<b>e</b>) <math display="inline"><semantics> <mrow> <mi>η</mi> </mrow> </semantics></math>, (<b>f</b>) <math display="inline"><semantics> <mrow> <mi>δ</mi> </mrow> </semantics></math>, (<b>g</b>) <math display="inline"><semantics> <mrow> <mi>ν</mi> </mrow> </semantics></math>, and (<b>h</b>) <math display="inline"><semantics> <mrow> <mi>b</mi> </mrow> </semantics></math>.</p>
Full article ">Figure 1 Cont.
<p><math display="inline"><semantics> <mrow> <mover accent="true"> <mrow> <mi>O</mi> </mrow> <mo>¯</mo> </mover> </mrow> </semantics></math> for different values of c by varying (<b>a</b>) <math display="inline"><semantics> <mrow> <mi>λ</mi> </mrow> </semantics></math>, (<b>b</b>) <math display="inline"><semantics> <mrow> <mi>α</mi> </mrow> </semantics></math>, (<b>c</b>) <math display="inline"><semantics> <mrow> <msub> <mrow> <mi>μ</mi> </mrow> <mrow> <mn>1</mn> </mrow> </msub> </mrow> </semantics></math>, (<b>d</b>) <math display="inline"><semantics> <mrow> <msub> <mrow> <mi>μ</mi> </mrow> <mrow> <mi>w</mi> </mrow> </msub> </mrow> </semantics></math>, (<b>e</b>) <math display="inline"><semantics> <mrow> <mi>η</mi> </mrow> </semantics></math>, (<b>f</b>) <math display="inline"><semantics> <mrow> <mi>δ</mi> </mrow> </semantics></math>, (<b>g</b>) <math display="inline"><semantics> <mrow> <mi>ν</mi> </mrow> </semantics></math>, and (<b>h</b>) <math display="inline"><semantics> <mrow> <mi>b</mi> </mrow> </semantics></math>.</p>
Full article ">Figure 2
<p><math display="inline"><semantics> <mrow> <msub> <mrow> <mi>P</mi> </mrow> <mrow> <mi>v</mi> </mrow> </msub> <mo>,</mo> <mo> </mo> <msub> <mrow> <mi>P</mi> </mrow> <mrow> <mi>b</mi> </mrow> </msub> <mo>,</mo> <mo> </mo> <msub> <mrow> <mi>P</mi> </mrow> <mrow> <mi>d</mi> </mrow> </msub> </mrow> </semantics></math>, and <math display="inline"><semantics> <mrow> <mi>U</mi> </mrow> </semantics></math> by varying (<b>a</b>) <math display="inline"><semantics> <mrow> <mi>λ</mi> </mrow> </semantics></math>, (<b>b</b>) <math display="inline"><semantics> <mrow> <mi>α</mi> </mrow> </semantics></math>, (<b>c</b>) <math display="inline"><semantics> <mrow> <msub> <mrow> <mi>μ</mi> </mrow> <mrow> <mn>1</mn> </mrow> </msub> </mrow> </semantics></math>, (<b>d</b>) <math display="inline"><semantics> <mrow> <msub> <mrow> <mi>μ</mi> </mrow> <mrow> <mi>w</mi> </mrow> </msub> </mrow> </semantics></math>, (<b>e</b>) <math display="inline"><semantics> <mrow> <mi>η</mi> </mrow> </semantics></math>, (<b>f</b>) <math display="inline"><semantics> <mrow> <mi>δ</mi> </mrow> </semantics></math>, (<b>g</b>) <math display="inline"><semantics> <mrow> <mi>ν</mi> </mrow> </semantics></math>, and (<b>h</b>) <math display="inline"><semantics> <mrow> <mi>b</mi> </mrow> </semantics></math>.</p>
Full article ">Figure 2 Cont.
<p><math display="inline"><semantics> <mrow> <msub> <mrow> <mi>P</mi> </mrow> <mrow> <mi>v</mi> </mrow> </msub> <mo>,</mo> <mo> </mo> <msub> <mrow> <mi>P</mi> </mrow> <mrow> <mi>b</mi> </mrow> </msub> <mo>,</mo> <mo> </mo> <msub> <mrow> <mi>P</mi> </mrow> <mrow> <mi>d</mi> </mrow> </msub> </mrow> </semantics></math>, and <math display="inline"><semantics> <mrow> <mi>U</mi> </mrow> </semantics></math> by varying (<b>a</b>) <math display="inline"><semantics> <mrow> <mi>λ</mi> </mrow> </semantics></math>, (<b>b</b>) <math display="inline"><semantics> <mrow> <mi>α</mi> </mrow> </semantics></math>, (<b>c</b>) <math display="inline"><semantics> <mrow> <msub> <mrow> <mi>μ</mi> </mrow> <mrow> <mn>1</mn> </mrow> </msub> </mrow> </semantics></math>, (<b>d</b>) <math display="inline"><semantics> <mrow> <msub> <mrow> <mi>μ</mi> </mrow> <mrow> <mi>w</mi> </mrow> </msub> </mrow> </semantics></math>, (<b>e</b>) <math display="inline"><semantics> <mrow> <mi>η</mi> </mrow> </semantics></math>, (<b>f</b>) <math display="inline"><semantics> <mrow> <mi>δ</mi> </mrow> </semantics></math>, (<b>g</b>) <math display="inline"><semantics> <mrow> <mi>ν</mi> </mrow> </semantics></math>, and (<b>h</b>) <math display="inline"><semantics> <mrow> <mi>b</mi> </mrow> </semantics></math>.</p>
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<p>Pareto front for health helpline service center.</p>
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<p>The histogram and the Kolmogorov-Smirnov test for the regression residuals.</p>
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<p>The impact of <math display="inline"><semantics> <mrow> <mi>α</mi> </mrow> </semantics></math> on <math display="inline"><semantics> <mrow> <mi>W</mi> </mrow> </semantics></math> (retrial queues with/without two-way communication).</p>
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<p>The impact of <math display="inline"><semantics> <mrow> <mi>δ</mi> </mrow> </semantics></math> on <math display="inline"><semantics> <mrow> <mn>1</mn> <mo>−</mo> <mi>U</mi> </mrow> </semantics></math> (two-way communication retrial queues with/without disasters).</p>
Full article ">
20 pages, 594 KiB  
Article
Solution of a Nonlinear Integral Equation Arising in the Moment Approximation of Spatial Logistic Dynamics
by Mikhail Nikolaev, Alexey Nikitin and Ulf Dieckmann
Mathematics 2024, 12(24), 4033; https://doi.org/10.3390/math12244033 - 23 Dec 2024
Viewed by 364
Abstract
We investigate a nonlinear integral equation derived through moment approximation from the individual-based representation of spatial logistic dynamics. The equation describes how the densities of pairs of individuals represented by points in continuous space are expected to equilibrate under spatially explicit birth–death processes [...] Read more.
We investigate a nonlinear integral equation derived through moment approximation from the individual-based representation of spatial logistic dynamics. The equation describes how the densities of pairs of individuals represented by points in continuous space are expected to equilibrate under spatially explicit birth–death processes characterized by constant fecundity with local natal dispersal and variable mortality determined by local competition. The equation is derived from a moment hierarchy truncated by a moment closure expressing the densities of triplets as a function of the densities of pairs. Focusing on results for individuals inhabiting two-dimensional habitats, we explore the solvability of the equation by introducing a dedicated space of functions that are integrable up to a constant. Using this function space, we establish sufficient conditions for the existence of solutions of the equation within a zero-centered ball. For illustration and further insights, we complement our analytical findings with numerical results. Full article
(This article belongs to the Collection Theoretical and Mathematical Ecology)
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Figure 1

Figure 1
<p>Visualization of the kernels describing competition and dispersal. Individuals are represented by points in a two-dimensional habitat. The strength according to which an individual A competes with individuals such as B is determined by the competition kernel, depicted here by variations in red shading. Similarly, the probability density according to which an individual C moves a newly produced offspring individual to locations such as D is determined by the dispersal kernel, depicted here by variations in blue shading.</p>
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<p>Solutions of the equilibrium equation. The continuous blue curves show the pair density <math display="inline"><semantics> <mrow> <mi>C</mi> <mo>(</mo> <mi>x</mi> <mo>)</mo> </mrow> </semantics></math> as a function of the pair distance <math display="inline"><semantics> <mrow> <mi>r</mi> <mo>=</mo> <mo>∥</mo> <mi>x</mi> <mo>∥</mo> </mrow> </semantics></math>. The dashed gray lines indicate <math display="inline"><semantics> <msup> <mi>N</mi> <mn>2</mn> </msup> </semantics></math>, i.e., the limit of <math display="inline"><semantics> <mrow> <mi>C</mi> <mo>(</mo> <mi>x</mi> <mo>)</mo> </mrow> </semantics></math> as <span class="html-italic">r</span> approaches infinity. (<b>a</b>) <math display="inline"><semantics> <mrow> <msub> <mi>σ</mi> <mi mathvariant="normal">m</mi> </msub> <mo>=</mo> <mn>0.02</mn> </mrow> </semantics></math>, <math display="inline"><semantics> <mrow> <msub> <mi>σ</mi> <mi mathvariant="normal">w</mi> </msub> <mo>=</mo> <mn>0.01</mn> </mrow> </semantics></math>; (<b>b</b>) <math display="inline"><semantics> <mrow> <msub> <mi>σ</mi> <mi mathvariant="normal">m</mi> </msub> <mo>=</mo> <msub> <mi>σ</mi> <mi mathvariant="normal">w</mi> </msub> <mo>=</mo> <mn>0.02</mn> </mrow> </semantics></math>; and (<b>c</b>) <math display="inline"><semantics> <mrow> <msub> <mi>σ</mi> <mi mathvariant="normal">m</mi> </msub> <mo>=</mo> <mn>0.01</mn> </mrow> </semantics></math>, <math display="inline"><semantics> <mrow> <msub> <mi>σ</mi> <mi mathvariant="normal">w</mi> </msub> <mo>=</mo> <mn>0.02</mn> </mrow> </semantics></math>. The smaller the ratio <math display="inline"><semantics> <mrow> <msub> <mi>σ</mi> <mi mathvariant="normal">m</mi> </msub> <mo>/</mo> <msub> <mi>σ</mi> <mi mathvariant="normal">w</mi> </msub> </mrow> </semantics></math>, the smaller the mean density <span class="html-italic">N</span>. Other parameters: <math display="inline"><semantics> <mrow> <mi>b</mi> <mo>=</mo> <mn>0.5</mn> </mrow> </semantics></math>, <math display="inline"><semantics> <mrow> <mi>d</mi> <mo>=</mo> <mn>0.01</mn> </mrow> </semantics></math>, <math display="inline"><semantics> <mrow> <mi>s</mi> <mo>=</mo> <mn>0.01</mn> </mrow> </semantics></math>, <math display="inline"><semantics> <mrow> <mi>α</mi> <mo>=</mo> <mi>β</mi> <mo>=</mo> <mn>1</mn> </mrow> </semantics></math>, and <math display="inline"><semantics> <mrow> <mi>γ</mi> <mo>=</mo> <mo>−</mo> <mn>0.5</mn> </mrow> </semantics></math>.</p>
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12 pages, 270 KiB  
Article
The Test of Sports and Folk Narratives with the Notion of Haram: Citing the Example of the Branch of Wrestling
by Ünsal Yılmaz Yeşildal, Doğukan Batur Alp Gülşen and Cihat Burak Korkmaz
Religions 2024, 15(11), 1311; https://doi.org/10.3390/rel15111311 - 26 Oct 2024
Cited by 1 | Viewed by 871
Abstract
Culture consists of material and spiritual values and tools that a nation has accumulated in the historical process. In addition to the most basic contexts such as language and religion, contexts such as sporting activities, art, public medicine, and the public calendar are [...] Read more.
Culture consists of material and spiritual values and tools that a nation has accumulated in the historical process. In addition to the most basic contexts such as language and religion, contexts such as sporting activities, art, public medicine, and the public calendar are also important environments that reveal their own cultural elements. Among these contexts, religion is very effective in shaping the daily life of the individual and, thus, society through the rules it enjoins. Religion does not dominate only the world of belief of the individual. Through the world of belief, it also directs their relations with the social institutions they are involved in. Sport is one of the most important activities and social institutions that stand out with various functions in daily life, with wrestling being one of the branches of sports that have emerged as a result of the imitation of the struggle of human beings with nature and other creatures with which they share nature. In particular, those involved in the nomadic way of life had to hunt in order not to starve and fight in order to survive. Wrestling, which emerged as a result of these obligations, held an important place among all Turks in the world for a period of time, especially in the transition periods of life, such as birth, marriage, and death. One of the conditions set forth by women as a condition of marriage was that their suitor defeated them in wrestling. Examples of this condition are also observed in literary texts belonging to different periods when Turks were not yet acquainted with Islam and the concepts of halal and haram, which entered their lives together with Islam. According to the provisions of the Holy Qur’an, right/unprohibited thoughts and actions are associated with the words good and halal, while wrong/prohibited thoughts and actions are associated with the words sin and haram. In this study, the social and cultural phases of wrestling as a sports branch among Turks in the historical process will be evaluated on the basis of the history of religions and religious references, in addition to the literary texts belonging to historical periods when Turks were members of different religions, in the context of two events that have been experienced and reported in the news. The study was carried out using the method of document analysis, a method of qualitative research, and the data obtained by this method were evaluated using content analysis. The narratives of Alıp Manaş, Alpamış, Alpamıs, Alıpmenşen, and Bamsı Beyrek, which are evaluated in this context, belong to the periods when the Turks had not been introduced to Islam or had only recently been introduced to it. Alıp Manaş was collated from different Turkic tribes such as the Altais, Alpamış from the Uzbeks, Alpamıs the Kazakhs/Karakalpaks, Alıpmenşen the Bashkirs/Tatars, and Bamsı Beyrek the Oghuz Turks. The narratives of Kirmanshah, Köse Kenan-Dânâ Hanım, Bey Böyrek, Shah Ismail, and Yaralı Mahmut, which are evaluated in the study, belong to the periods when the Turks became Muslim en masse, and are related only among the Oghuz Turks. These narratives are included in the study because they are similar to Alıp Manaş, Alpamış, Alpamıs, Alıpmenşen, and Bamsı Beyrek and they belong to the period when Islam was largely established among the Turkish masses in Anatolia. The effect of the new religion on wrestling, which is a branch of sport, will be revealed through these narratives belonging to different tribes and religious periods. Once more, an event that occurred in recent history, and was the subject of the news, was subjected to document analysis, and content analysis was carried out through the text of the news and evaluated in the context of the study. This study aims to explain the effect of religious rules on sports branches with theological, folkloric, and sociological references based on ancient literary texts belonging to the Turks and two incidents which were experienced. Full article
(This article belongs to the Special Issue Sport and Religion: Continuities, Connections, Concerns)
10 pages, 289 KiB  
Article
Universes Emerging from Nothing and Disappearing into Nothing as an Endless Cosmological Process
by Leonid Marochnik
Universe 2024, 10(10), 388; https://doi.org/10.3390/universe10100388 - 3 Oct 2024
Viewed by 724
Abstract
The equation of state of quantum fluctuations of the gravitational field of the universe depends on H4, where H is the Hubble constant. This means that it is invariant with respect to the Wick rotation, i.e., the transition from Lorentzian space-time [...] Read more.
The equation of state of quantum fluctuations of the gravitational field of the universe depends on H4, where H is the Hubble constant. This means that it is invariant with respect to the Wick rotation, i.e., the transition from Lorentzian space-time to Euclidean space-time and vice versa. It is shown that the quantum birth of universes from Euclidean space-time, i.e., from nothing, and their quantum disappearance to nothing (return to Euclidean space-time) by the time the density of the matter filling the universe becomes negligible could be a likely cosmological scenario. On an infinite time axis, this is an endless process of birth and death of universes appearing and disappearing and replacing each other. Within this scenario, our current universe is going to disappear into nothing at z0.68, i.e., after 18.37 billion years, and the lifetime of our universe and similar universes is about 32 billion years. Full article
(This article belongs to the Special Issue Cosmological Models of the Universe)
16 pages, 1699 KiB  
Article
Characteristics Analysis and Modeling of Integrated Sensing and Communication Channel for Unmanned Aerial Vehicle Communications
by Xinru Li, Yu Liu, Xinrong Zhang, Yi Zhang, Jie Huang and Ji Bian
Drones 2024, 8(10), 538; https://doi.org/10.3390/drones8100538 - 1 Oct 2024
Viewed by 1002
Abstract
As an important part of 6th generation (6G) communication, integrated sensing and communication (ISAC) for unmanned aerial vehicle (UAV) communication has attracted more and more attention. The UAV ISAC channel model considering the space-time evolution of joint and shared clusters is the basis [...] Read more.
As an important part of 6th generation (6G) communication, integrated sensing and communication (ISAC) for unmanned aerial vehicle (UAV) communication has attracted more and more attention. The UAV ISAC channel model considering the space-time evolution of joint and shared clusters is the basis of UAV ISAC system design and network evaluation. This paper introduces the UAV ISAC channel characteristics analysis and modeling method. In the UAV ISAC network, the channel consists of a communication channel and a sensing channel. A joint channel parameter is a combination of all (communication and sensing) multiple path component (MPC) parameter sets, while a shared path is the intersection of the communication path and sensing path that have some of the same MPC parameters. Based on the data collected from a ray-tracing (RT) UAV-to-ground scenario, the joint paths and shared paths of ISAC channels are clustered. Then, by introducing the occurrence and disappearance of clusters based on the birth–death (B–D) process, the space-time evolution of different clusters is described, and the influence of the addition of sensing clusters and the change in flight altitude on the B–D process is explored. Finally, the effects of the sensing cluster and flight altitude on the UAV ISAC channel characteristics, including the angle, time–varying characteristics, and sharing degree (SD), are analyzed. The related UAV ISAC channel characteristics analysis can provide reference for the future development of UAV ISAC systems. Full article
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<p>The architecture of clustering and evolution phenomenon for UAV-to-ground ISAC communication channels.</p>
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<p>The flight details for UAV ISAC scenarios of (<b>a</b>) satellite image and (<b>b</b>) simulation scene.</p>
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<p>Clustering evaluation by combined indicator in (<b>a</b>) 20 m conditions and (<b>b</b>) 30 m conditions.</p>
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<p>Matching between the clustering results and the simulation results.</p>
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<p>The clustering results of (<b>a</b>) 3D perspective, (<b>b</b>) joint clusters, (<b>c</b>) communication clusters and (<b>d</b>) shared clusters.</p>
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<p>The flowchart of UAV ISAC channel clustering process.</p>
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<p>Channel clustering and tracking process at different snapshots of (<b>a</b>) S<sub>20</sub>, (<b>b</b>) S<sub>30</sub>, (<b>c</b>) S<sub>40</sub> and (<b>d</b>) S<sub>50</sub>.</p>
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<p>Time-varying cluster tracking results in (<b>a</b>) communication clusters at 20 m, (<b>b</b>) shared clusters at 20 m, (<b>c</b>) communication clusters at 30 m and (<b>d</b>) shared clusters at 30 m.</p>
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<p>The CDFs of cluster lifetime under different height.</p>
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<p>The count histogram of the cluster number in joint and communication cluster at (<b>a</b>) 20 m and (<b>b</b>) 30 m.</p>
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<p>The CDFs of cluster RMS DSs at different heights: (<b>a</b>) 20 m height and (<b>b</b>) 30 m height.</p>
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<p>Simulation CDFs of SDs and SDc with varying heights.</p>
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<p>The CDFs of RMS DS with RT simulation and model simulation data.</p>
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8 pages, 2276 KiB  
Case Report
Ductus Venosus Agenesis in Monochorionic Twin Pregnancies Complicated by Fetal Growth Restriction: When to Deliver?
by Eleonora Torcia, Alessandra Familiari, Elvira Passananti, Giulia di Marco, Federica Romanzi, Mariarita Trapani, Daniela Visconti, Antonio Lanzone and Elisa Bevilacqua
Diagnostics 2024, 14(19), 2147; https://doi.org/10.3390/diagnostics14192147 - 26 Sep 2024
Viewed by 743
Abstract
Introduction: The prevalence of ductus venosus agenesis (ADV) in singleton pregnancies ranges from 0.04% to 0.15%, while its prevalence in twins remains largely unknown. To our knowledge, in the literature, there is only a single case report of a monochorionic diamniotic (MCDA) pregnancy [...] Read more.
Introduction: The prevalence of ductus venosus agenesis (ADV) in singleton pregnancies ranges from 0.04% to 0.15%, while its prevalence in twins remains largely unknown. To our knowledge, in the literature, there is only a single case report of a monochorionic diamniotic (MCDA) pregnancy complicated by ADV. Fetuses with ADV are at increased risk for congenital cardiac disease, heart failure, and fetal growth restriction (FGR). Consequently, these pregnancies have a heightened risk of experiencing an adverse outcome, like stillbirth and neonatal or infant death. Closer antenatal monitoring is warranted when ADV is suspected. Currently, there are no guidelines regarding the standard of care in cases of ADV and no recommendations for the timing of delivery in either singleton or twin pregnancies. Cases: This study aims to provide a comprehensive overview of the management of twin pregnancies complicated by ADV, featuring two cases of MC twins with concurrent sFGR and ADV in one twin. Discussion: These pregnancies experienced completely different outcomes, underscoring the necessity for personalized management tailored to the specific risk factors present in each pregnancy. Typically, in MCDA pregnancies with severe sFGR (type II and III), delivery represents the most reasonable option when venous Doppler abnormalities are identified. However, the absence of the DV complicates the management and the process of decision-making regarding the timing of delivery in cases of sFGR and ADV. We emphasize that effective decision-making should be guided by the presence of additional risk factors, including velamentous insertion, significant estimated fetal weight discordance, and progressive deterioration of the Doppler over time. Conclusions: Our experience suggests that these factors are strongly correlated with poorer outcomes. Given this context, could it be acceptable, in the case of MC pregnancy complicated by severe sFGR and ADV, with worsening findings and additional risk factors (e.g., velamentous insertion, severe birth weight discrepancy), to anticipate the time of delivery starting from 30 weeks of gestational age? Full article
(This article belongs to the Special Issue Diagnosis and Management of Perinatal Medicine)
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Figure 1

Figure 1
<p>Main ultrasound characteristics: (<b>a.1</b>) velamentous insertion highlighted by ➭ and (<b>a.2</b>) ADV and UV drainage in the IVC highlighted by ★, in the first case; (<b>b.1</b>) marginal insertion highlighted by ➭ and (<b>b.2</b>) ADV and UV drainage in the IVC highlighted by ★, in the second case.</p>
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<p>Placenta after color-dye injection (for twin I: yellow vein, green artery; for twin II: red vein, blue artery). (<b>A</b>) Discordant umbilical cords’ insertion (white arrows) and placental anastomosis in the first case, after color-dye injection technique. (<b>B</b>) Concordant umbilical cords’ insertion (white arrows) and placental anastomosis in the second case, after color-dye injection technique.</p>
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14 pages, 3615 KiB  
Article
Analyzing the Impact of Deep Excavation on Retaining Structure Deformation Based on Element Tracking
by Wen Tan, Zhenyu Lei, Yanhong Wang, Jinsong Liu, Pengbang Lai, Yuan Mei, Wenzhan Liu and Dongbo Zhou
Buildings 2024, 14(10), 3069; https://doi.org/10.3390/buildings14103069 - 25 Sep 2024
Viewed by 864
Abstract
In the simulation of foundation pit excavation, the traditional element birth–death method commonly used tends to encounter issues such as uncoordinated deformation and changes in the constitutive model, affecting the accuracy of the prediction results. To address these issues, this study proposes the [...] Read more.
In the simulation of foundation pit excavation, the traditional element birth–death method commonly used tends to encounter issues such as uncoordinated deformation and changes in the constitutive model, affecting the accuracy of the prediction results. To address these issues, this study proposes the use of element tracking. By duplicating elements for temporary supports or structures requiring changes in material properties and appropriately activating or deactivating them at the right moments, the simulation of the foundation pit excavation process can be achieved more precisely. Using the construction process of the Tangxi Passenger Transport Station’s comprehensive transportation hub foundation pit as an example, this study applied the proposed simulation method and compared the results with actual measurements, demonstrating its effectiveness. This research offers a more accurate approach for simulating foundation pit excavation and provides a reference for similar numerical simulation problems. Full article
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Figure 1
<p>Research map of this paper.</p>
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<p>Schematic diagram of the birth–death element method.</p>
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<p>Station structure schematic diagram.</p>
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<p>Pit finite element model schematic diagram.</p>
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<p>Pit finite element mesh division schematic diagram.</p>
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<p>Geological horizontal displacement contour map for deactivated transverse section of excavation pit.</p>
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<p>Layout diagram of monitoring points from the top view.</p>
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<p>Cumulative horizontal displacement at the top of the wall–time curve diagram.</p>
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<p>Cumulative vertical displacement at the top of the wall−time curve diagram.</p>
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<p>Cumulative horizontal displacement at the top of the pit wall for condition 5 with com−parisons.</p>
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<p>Contour diagram of numerical simulation analysis for horizontal displacement of the wall.</p>
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27 pages, 1590 KiB  
Article
Sojourn Time Analysis of a Single-Server Queue with Single- and Batch-Service Customers
by Yusei Koyama, Ayane Nakamura and Tuan Phung-Duc
Mathematics 2024, 12(18), 2820; https://doi.org/10.3390/math12182820 - 11 Sep 2024
Viewed by 847
Abstract
There are various types of sharing economy services, such as ride-sharing and shared-taxi rides. Motivated by these services, we consider a single-server queue in which customers probabilistically select the type of service, that is, the single service or batch service, or other services [...] Read more.
There are various types of sharing economy services, such as ride-sharing and shared-taxi rides. Motivated by these services, we consider a single-server queue in which customers probabilistically select the type of service, that is, the single service or batch service, or other services (e.g., train). In the proposed model, which is denoted by the M+M(K)/M/1 queue, we assume that the arrival process of all the customers follows a Poisson distribution, the batch size is constant, and the common service time (for the single- and batch-service customers) follows an exponential distribution. In this model, the derivation of the sojourn time distribution is challenging because the sojourn time of a batch-service customer is not determined upon arrival but depends on single customers who arrive later. This results in a two-dimensional recursion, which is not generally solvable, but we made it possible by utilizing a special structure of our model. We present an analysis using a quasi-birth-and-death process, deriving the exact and approximated sojourn time distributions (for the single-service customers, batch-service customers, and all the customers). Through numerical experiments, we demonstrate that the approximated sojourn time distribution is sufficiently accurate compared to the exact sojourn time distributions. We also present a reasonable approximation for the distribution of the total number of customers in the system, which would be challenging with a direct-conventional method. Furthermore, we presented an accurate approximation method for a more general model where the service time of single-service customers and that of batch-service customers follow two distinct distributions, based on our original model. Full article
(This article belongs to the Special Issue Advances in Queueing Theory and Applications)
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Figure 1
<p>Schematic of application for the M+M(<span class="html-italic">K</span>)/M/1 queue in the context of transportation mode-selection problem.</p>
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<p>State transition diagram of the M+M<math display="inline"><semantics> <mrow> <mo>(</mo> <mi>K</mi> <mo>)</mo> </mrow> </semantics></math>/M/1 queue.</p>
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<p>Numerical results of <math display="inline"><semantics> <mrow> <mi>E</mi> <mrow> <mo>[</mo> <mi>L</mi> <mo>]</mo> </mrow> <mo>,</mo> <mi>E</mi> <mrow> <mo>[</mo> <msub> <mi>L</mi> <mi>s</mi> </msub> <mo>]</mo> </mrow> </mrow> </semantics></math>, and <math display="inline"><semantics> <mrow> <mo>[</mo> <msub> <mi>E</mi> <mi>b</mi> </msub> <mo>]</mo> </mrow> </semantics></math> for <math display="inline"><semantics> <mi>λ</mi> </semantics></math> (<math display="inline"><semantics> <mrow> <mi>K</mi> <mo>=</mo> <mn>3</mn> </mrow> </semantics></math>).</p>
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<p>Numerical results of <math display="inline"><semantics> <mrow> <mi>E</mi> <mrow> <mo>[</mo> <mi>L</mi> <mo>]</mo> </mrow> <mo>,</mo> <mi>E</mi> <mrow> <mo>[</mo> <msub> <mi>L</mi> <mi>s</mi> </msub> <mo>]</mo> </mrow> </mrow> </semantics></math>, and <math display="inline"><semantics> <mrow> <mo>[</mo> <msub> <mi>E</mi> <mi>b</mi> </msub> <mo>]</mo> </mrow> </semantics></math> for <math display="inline"><semantics> <mi>λ</mi> </semantics></math> (<math display="inline"><semantics> <mrow> <mi>K</mi> <mo>=</mo> <mn>5</mn> </mrow> </semantics></math>).</p>
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<p>Numerical results of <math display="inline"><semantics> <mrow> <mi>E</mi> <mo>[</mo> <mi>W</mi> <mo>]</mo> </mrow> </semantics></math> for <math display="inline"><semantics> <mi>λ</mi> </semantics></math> and <span class="html-italic">K</span>.</p>
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<p>Numerical results of <math display="inline"><semantics> <mrow> <mi>E</mi> <mrow> <mo>[</mo> <mi>L</mi> <mo>]</mo> </mrow> <mo>,</mo> <mi>E</mi> <mrow> <mo>[</mo> <msub> <mi>L</mi> <mi>s</mi> </msub> <mo>]</mo> </mrow> </mrow> </semantics></math>, and <math display="inline"><semantics> <mrow> <mo>[</mo> <msub> <mi>E</mi> <mi>b</mi> </msub> <mo>]</mo> </mrow> </semantics></math> for <math display="inline"><semantics> <mi>λ</mi> </semantics></math> (<math display="inline"><semantics> <mrow> <mi>K</mi> <mo>=</mo> <mn>8</mn> </mrow> </semantics></math>).</p>
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<p>Numerical results for <math display="inline"><semantics> <mrow> <msubsup> <mi>f</mi> <mi>s</mi> <mo>*</mo> </msubsup> <mrow> <mo>(</mo> <mi>t</mi> <mo>)</mo> </mrow> </mrow> </semantics></math>.</p>
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<p>Numerical results for <math display="inline"><semantics> <mrow> <msubsup> <mi>f</mi> <mi>b</mi> <mo>*</mo> </msubsup> <mrow> <mo>(</mo> <mi>t</mi> <mo>)</mo> </mrow> </mrow> </semantics></math>.</p>
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<p>Numerical results for <math display="inline"><semantics> <mrow> <msup> <mi>f</mi> <mo>*</mo> </msup> <mrow> <mo>(</mo> <mi>t</mi> <mo>)</mo> </mrow> </mrow> </semantics></math>.</p>
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<p><math display="inline"><semantics> <mrow> <msub> <mi>f</mi> <mrow> <mi>s</mi> <mi>s</mi> </mrow> </msub> <mrow> <mo>(</mo> <mi>t</mi> <mo>)</mo> </mrow> </mrow> </semantics></math> for <math display="inline"><semantics> <mrow> <mi>K</mi> <mo>=</mo> <mn>3</mn> </mrow> </semantics></math>.</p>
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<p><math display="inline"><semantics> <mrow> <msub> <mi>f</mi> <mrow> <mi>s</mi> <mi>s</mi> </mrow> </msub> <mrow> <mo>(</mo> <mi>t</mi> <mo>)</mo> </mrow> </mrow> </semantics></math> for <math display="inline"><semantics> <mrow> <mi>K</mi> <mo>=</mo> <mn>5</mn> </mrow> </semantics></math>.</p>
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<p><math display="inline"><semantics> <mrow> <msub> <mi>f</mi> <mrow> <mi>s</mi> <mi>s</mi> </mrow> </msub> <mrow> <mo>(</mo> <mi>t</mi> <mo>)</mo> </mrow> </mrow> </semantics></math> for <math display="inline"><semantics> <mrow> <mi>K</mi> <mo>=</mo> <mn>8</mn> </mrow> </semantics></math>.</p>
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<p><math display="inline"><semantics> <mrow> <msub> <mi>f</mi> <mrow> <mi>w</mi> <mi>s</mi> </mrow> </msub> <mrow> <mo>(</mo> <mi>t</mi> <mo>)</mo> </mrow> </mrow> </semantics></math> for <math display="inline"><semantics> <mrow> <mi>K</mi> <mo>=</mo> <mn>3</mn> </mrow> </semantics></math>.</p>
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<p><math display="inline"><semantics> <mrow> <msub> <mi>f</mi> <mrow> <mi>w</mi> <mi>s</mi> <mi>b</mi> <mi>s</mi> </mrow> </msub> <mrow> <mo>(</mo> <mi>t</mi> <mo>)</mo> </mrow> </mrow> </semantics></math> for <math display="inline"><semantics> <mrow> <mi>K</mi> <mo>=</mo> <mn>3</mn> </mrow> </semantics></math>.</p>
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<p><math display="inline"><semantics> <mrow> <msub> <mi>f</mi> <mrow> <mi>a</mi> <mi>l</mi> <mi>l</mi> </mrow> </msub> <mrow> <mo>(</mo> <mi>t</mi> <mo>)</mo> </mrow> </mrow> </semantics></math> for <math display="inline"><semantics> <mrow> <mi>K</mi> <mo>=</mo> <mn>3</mn> </mrow> </semantics></math>.</p>
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<p><math display="inline"><semantics> <mrow> <msub> <mi>f</mi> <mrow> <mi>w</mi> <mi>s</mi> <mi>b</mi> <mi>s</mi> </mrow> </msub> <mrow> <mo>(</mo> <mi>t</mi> <mo>)</mo> </mrow> </mrow> </semantics></math> for <math display="inline"><semantics> <mrow> <mi>K</mi> <mo>=</mo> <mn>20</mn> </mrow> </semantics></math>.</p>
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<p><math display="inline"><semantics> <mrow> <msub> <mi>f</mi> <mrow> <mi>w</mi> <mi>s</mi> <mi>b</mi> <mi>s</mi> </mrow> </msub> <mrow> <mo>(</mo> <mi>t</mi> <mo>)</mo> </mrow> </mrow> </semantics></math> for <math display="inline"><semantics> <mrow> <mi>K</mi> <mo>=</mo> <mn>50</mn> </mrow> </semantics></math>.</p>
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<p><math display="inline"><semantics> <mrow> <msubsup> <mi>f</mi> <mi>b</mi> <mo>*</mo> </msubsup> <mrow> <mo>(</mo> <mi>t</mi> <mo>)</mo> </mrow> </mrow> </semantics></math> for <math display="inline"><semantics> <mrow> <msub> <mi>p</mi> <mi>b</mi> </msub> <mo>=</mo> <mn>1</mn> <mo>,</mo> <msub> <mi>p</mi> <mi>s</mi> </msub> <mo>=</mo> <mn>0</mn> </mrow> </semantics></math>.</p>
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<p>Comparison between previous studies and our study [<a href="#B30-mathematics-12-02820" class="html-bibr">30</a>,<a href="#B31-mathematics-12-02820" class="html-bibr">31</a>].</p>
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<p>Comparison of the approximation and simulation for <math display="inline"><semantics> <mrow> <msub> <mi>p</mi> <mi>s</mi> </msub> <mo>=</mo> <mn>0</mn> </mrow> </semantics></math> and <math display="inline"><semantics> <mrow> <mi>λ</mi> <mo>=</mo> <mn>4</mn> </mrow> </semantics></math>.</p>
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<p>Comparison of the approximation and simulation for <math display="inline"><semantics> <mrow> <msub> <mi>p</mi> <mi>s</mi> </msub> <mo>=</mo> <mn>0</mn> </mrow> </semantics></math> and <math display="inline"><semantics> <mrow> <mi>λ</mi> <mo>=</mo> <mn>6</mn> </mrow> </semantics></math>.</p>
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<p>Comparison of the approximation and simulation for <math display="inline"><semantics> <mrow> <msub> <mi>p</mi> <mi>s</mi> </msub> <mo>=</mo> <mn>0</mn> </mrow> </semantics></math> and <math display="inline"><semantics> <mrow> <mi>λ</mi> <mo>=</mo> <mn>8</mn> </mrow> </semantics></math>.</p>
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<p>Numerical results of the distribution of the number of single-service customers (<math display="inline"><semantics> <mrow> <msub> <mi>p</mi> <mi>s</mi> </msub> <mo>=</mo> <mn>0.5</mn> <mo>,</mo> <msub> <mi>p</mi> <mi>b</mi> </msub> <mo>=</mo> <mn>0.5</mn> </mrow> </semantics></math>).</p>
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<p>Numerical results of the distribution of the number of single-service customers (<math display="inline"><semantics> <mrow> <msub> <mi>p</mi> <mi>s</mi> </msub> <mo>=</mo> <mn>0.2</mn> <mo>,</mo> <msub> <mi>p</mi> <mi>b</mi> </msub> <mo>=</mo> <mn>0.8</mn> </mrow> </semantics></math>).</p>
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<p>Numerical results of the distribution of the number of batch-service customers (<math display="inline"><semantics> <mrow> <msub> <mi>p</mi> <mi>s</mi> </msub> <mo>=</mo> <mn>0.5</mn> <mo>,</mo> <msub> <mi>p</mi> <mi>b</mi> </msub> <mo>=</mo> <mn>0.5</mn> </mrow> </semantics></math>).</p>
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<p>Numerical results of the distribution of the number of batch-service customers (<math display="inline"><semantics> <mrow> <msub> <mi>p</mi> <mi>s</mi> </msub> <mo>=</mo> <mn>0.2</mn> <mo>,</mo> <msub> <mi>p</mi> <mi>b</mi> </msub> <mo>=</mo> <mn>0.8</mn> </mrow> </semantics></math>).</p>
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<p>Numerical results of mean sojourn time for single customer for <math display="inline"><semantics> <mi>λ</mi> </semantics></math> and <math display="inline"><semantics> <mi>μ</mi> </semantics></math>.</p>
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<p>Numerical results of mean sojourn time for batch customer for <math display="inline"><semantics> <mi>λ</mi> </semantics></math> and <math display="inline"><semantics> <mi>μ</mi> </semantics></math>.</p>
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17 pages, 1295 KiB  
Article
Is It Possible to Prevent the Thanatogenetic Processes in Premature Babies?
by Sinziana Andra Ghitoi, Mariana Deacu, Mariana Aschie, Manuela Enciu, Anca Florentina Mitroi, Georgeta Camelia Cozaru, Antonela Anca Nicolau, Cristian Ionut Orasanu, Oana Andreea Ursica and Raluca Ioana Voda
Clin. Pract. 2024, 14(5), 1801-1817; https://doi.org/10.3390/clinpract14050144 - 2 Sep 2024
Viewed by 799
Abstract
Preterm births comprise all pregnancies coming to an end before the gestational age of 37 weeks and remain the leading cause of death in children under 5 years old despite efforts to reduce their occurrence. We aim to analyze all morbidity and mortality [...] Read more.
Preterm births comprise all pregnancies coming to an end before the gestational age of 37 weeks and remain the leading cause of death in children under 5 years old despite efforts to reduce their occurrence. We aim to analyze all morbidity and mortality data to understand causes and risk factors, helping in prevention efforts. This study includes 140 cases collected during 2018–2022. Demographic, maternal, and thanatogenetic data were statistically analyzed. We observed an upward slope of stillborn babies. In the case of live-born premature, the average survival was 301.76 h. The multivariate analysis noted that extremely low birth weight (HR = 5.141) and very low birth weight (HR = 4.177) are risk factors involved in mortality. Increased parity was associated with premature births with low and very low birth weight (p = 0.019). We observed that a mother’s age of over 30 years is predictable for the development of pregnancy-induced hypertension. Cerebral and pulmonary hemorrhages were the most common intermediate morbid conditions, with prematurity and plurivisceral hemorrhages serving as their root causes. We have identified that anthropometric measurements have a high predictability on malformed babies. The identified associations indicate a shared mechanism for certain lesion processes, which can help optimize resources for predicting and preventing preterm neonatal issues. Full article
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<p>Flow chart with the studied batch.</p>
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<p>Graph showing the upward trend of intrauterine deaths of premature babies and the downward trend of deaths in the first year of premature babies born alive.</p>
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<p>The ROC curve underlines the anthropometric changes in malformed premature babies (Red line represents the ROC curve for a random guess. The blue lines represent the distribution of the cases.). (<b>A</b>) Weight. (<b>B</b>) Length. (<b>C</b>) Cranial perimeter. (<b>D</b>) Chest circumference. (<b>E</b>) Abdominal circumference.</p>
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13 pages, 4563 KiB  
Article
Sudden Intrauterine Unexplained Death (SIUD) and Oxidative Stress: Placental Immunohistochemical Markers
by Angelo Montana, Letizia Alfieri, Raffaella Marino, Pantaleo Greco, Cristina Taliento, Ezio Fulcheri, Anastasio Tini, Francesca Buffelli and Margherita Neri
Cells 2024, 13(16), 1347; https://doi.org/10.3390/cells13161347 - 13 Aug 2024
Cited by 1 | Viewed by 1134
Abstract
Background: Intrauterine fetal death and perinatal death represent one of the most relevant medical scientific problems since, in many cases, even after extensive investigation, the causes remain unknown. The considerable increase in medical legal litigation in the obstetrical field that has witnessed in [...] Read more.
Background: Intrauterine fetal death and perinatal death represent one of the most relevant medical scientific problems since, in many cases, even after extensive investigation, the causes remain unknown. The considerable increase in medical legal litigation in the obstetrical field that has witnessed in recent years, especially in cases of stillborn births, has simultaneously involved the figure of the forensic pathologist in scientific research aimed at clarifying the pathophysiological processes underlying stillbirth. Methods: our study aims to analyze cases of sudden intrauterine unexplained death syndrome (SIUD) to evaluate the role of oxidative stress in the complex pathogenetic process of stillbirth. In particular, the immunohistochemical expression of specific oxidative stress markers (NOX2, NT, iNOS, 8-HODG, IL-6) was evaluated in tissue samples of placentas of SIUDs belonging to the extensive case series (20 cases), collected from autopsy cases of the University of Ferrara and Politecnica delle Marche between 2017 and 2023. Results: The study demonstrated the involvement of oxidative stress in intrauterine fetal deaths in the placenta of the cases examined. In SIUD, the most expressed oxidative stress markers were NOX2 and 8-HODG. Conclusions: The study contributes to investigating the role of oxidative stress in modulating different pathways in unexplained intrauterine fetal death (SIUD) tissues. Full article
(This article belongs to the Special Issue Signaling Pathways in Pregnancy)
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Figure 1
<p>In the image, at 40× magnification, the immunohistochemical reaction against the anti-NOX2 antibody: (<b>A</b>) Group 1 (N = 15), the strong NOX2 diffuse immunopositivity localized in the placental tissue, central area. (<b>B</b>) Group 2 (N = 10), mild immunoreaction to NOX2 in the control tissue. In the graph at the bottom, the statistical representation, **** (statistically significant), <span class="html-italic">p</span> &lt; 0.0001.</p>
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<p>The results of the immunoreaction, at 40× magnification, to NT: (<b>A</b>) Group 1 (N = 15), overexpression of diffuse NT in the placenta of the cases, central part; (<b>B</b>) Group 2 (N = 10), low antibody reaction in the control tissue. In the lower part, the statistical comparison is represented graphically, **** (statistically significant): <span class="html-italic">p</span> &lt; 0.0001.</p>
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<p>The results of immunohistochemical staining, at 40× magnification, with the marker iNOS: (<b>A</b>), in Group 1 (N = 15), the placental tissue expresses intermediate immunoreactivity for iNOS; (<b>B</b>) Group 2 (N = 10), minimal immunoreactivity in the control. The graphical representation of the statistical analysis is placed at the bottom of the figure, **** (statistically significant): <span class="html-italic">p</span> &lt; 0.0001.</p>
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<p>8-HODG immunohistochemical results in figure at 40× magnification: (<b>A</b>) Group 1 (N = 15): a diffuse and intense positive immunoreaction localized in placental tissue, central part, of 8-HODG; (<b>B</b>) Group 2 (N = 10): basal reaction in the control case. The graphical representation of the statistical analysis is collocated in the lower part of the figure, **** (statistically significant): <span class="html-italic">p</span> &lt; 0.0001.</p>
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<p>IL-6 immunohistochemical results at 40× magnification: (<b>A</b>) Group 1 (N = 15), shows a diffuse immunohistochemical intermediate reaction in the placental tissue of a case for the IL-6 marker; (<b>B</b>) in the image appreciates the very moderate reaction in Group 2 (N = 10), in the control case. The lower part of the figure is a graph of statistical analysis, **** (statistically significant): <span class="html-italic">p</span> &lt; 0.0001.</p>
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<p>The graphical representation of the comparison of the expression between the various markers.</p>
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17 pages, 731 KiB  
Article
New Computer Experiment Designs with Area-Interaction Point Processes
by Ahmed Ait Ameur, Hichem Elmossaoui and Nadia Oukid
Mathematics 2024, 12(15), 2397; https://doi.org/10.3390/math12152397 - 31 Jul 2024
Viewed by 858
Abstract
This article presents a novel method for constructing computer experiment designs based on the theory of area-interaction point processes. This method is essential for capturing the interactions between different elements within a modeled system, offering a more flexible and adaptable approach compared with [...] Read more.
This article presents a novel method for constructing computer experiment designs based on the theory of area-interaction point processes. This method is essential for capturing the interactions between different elements within a modeled system, offering a more flexible and adaptable approach compared with traditional mathematical modeling. Unlike conventional rough models that rely on simplified equations, our method employs the Markov Chain Monte Carlo (MCMC) method and the Metropolis–Hastings algorithm combined with Voronoi tessellations. It uses a new dynamic called homogeneous birth and death dynamics of a set of points to generate the designs. This approach does not require the development of specific mathematical models for each system under study, making it universally applicable while achieving comparable results. Furthermore, we provide an in-depth analysis of the convergence properties of the Markov Chain to ensure the reliability of the generated designs. An expanded literature review situates our work within the context of existing research, highlighting its unique contributions and advancements. A comparison between our approach and other existing computer experiment designs has been performed. Full article
(This article belongs to the Special Issue Stochastic Processes: Theory, Simulation and Applications)
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Figure 1
<p>Example of Voronoi tessellations generated for 10 and 20 points on <math display="inline"><semantics> <msup> <mrow> <mfenced separators="" open="[" close="]"> <mn>0</mn> <mo>,</mo> <mn>1</mn> </mfenced> </mrow> <mn>2</mn> </msup> </semantics></math>.</p>
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<p>Example of <math display="inline"><semantics> <mrow> <msub> <mi>U</mi> <mi>r</mi> </msub> <mrow> <mo>(</mo> <mi>x</mi> <mo>)</mo> </mrow> </mrow> </semantics></math> for 20 points in the unit square <math display="inline"><semantics> <msup> <mrow> <mfenced separators="" open="[" close="]"> <mn>0</mn> <mo>,</mo> <mn>1</mn> </mfenced> </mrow> <mn>2</mn> </msup> </semantics></math>.</p>
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<p>On the left, an initial configuration of 25 points with <math display="inline"><semantics> <mrow> <mi>m</mi> <mfenced separators="" open="(" close=")"> <msub> <mi>U</mi> <mi>r</mi> </msub> <mrow> <mo>(</mo> <mi>x</mi> <mo>)</mo> </mrow> </mfenced> <mo>=</mo> <mn>0.5408</mn> </mrow> </semantics></math>, and on the right, a final configuration for <math display="inline"><semantics> <mrow> <mi>γ</mi> <mo>=</mo> <mn>3</mn> </mrow> </semantics></math> and <math display="inline"><semantics> <mrow> <mi>r</mi> <mo>=</mo> <mn>0.1</mn> </mrow> </semantics></math> with <math display="inline"><semantics> <mrow> <mi>m</mi> <mfenced separators="" open="(" close=")"> <msub> <mi>U</mi> <mi>r</mi> </msub> <mrow> <mo>(</mo> <mi>x</mi> <mo>)</mo> </mrow> </mfenced> <mo>=</mo> <mn>0.7594</mn> </mrow> </semantics></math>.</p>
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<p>On the left, an initial configuration of 25 points with <math display="inline"><semantics> <mrow> <mi>m</mi> <mfenced separators="" open="(" close=")"> <msub> <mi>U</mi> <mi>r</mi> </msub> <mrow> <mo>(</mo> <mi>x</mi> <mo>)</mo> </mrow> </mfenced> <mo>=</mo> <mn>0.1040</mn> </mrow> </semantics></math>, and on the right, a final configuration for <math display="inline"><semantics> <mrow> <mi>γ</mi> <mo>=</mo> <mn>3</mn> </mrow> </semantics></math> and <math display="inline"><semantics> <mrow> <mi>r</mi> <mo>=</mo> <mn>0.1</mn> </mrow> </semantics></math> with <math display="inline"><semantics> <mrow> <mi>m</mi> <mfenced separators="" open="(" close=")"> <msub> <mi>U</mi> <mi>r</mi> </msub> <mrow> <mo>(</mo> <mi>x</mi> <mo>)</mo> </mrow> </mfenced> <mo>=</mo> <mn>0.1047</mn> </mrow> </semantics></math>.</p>
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<p>On the left, a configuration of 25 points with <math display="inline"><semantics> <mrow> <mi>γ</mi> <mo>=</mo> <mn>3</mn> </mrow> </semantics></math> and <math display="inline"><semantics> <mrow> <mi>r</mi> <mo>=</mo> <mn>0.05</mn> </mrow> </semantics></math> with <math display="inline"><semantics> <mrow> <mi>m</mi> <mfenced separators="" open="(" close=")"> <msub> <mi>U</mi> <mi>r</mi> </msub> <mrow> <mo>(</mo> <mi>x</mi> <mo>)</mo> </mrow> </mfenced> <mo>=</mo> <mn>0.1960</mn> </mrow> </semantics></math>, and on the right, a configuration of 25 points with <math display="inline"><semantics> <mrow> <mi>γ</mi> <mo>=</mo> <mn>3</mn> </mrow> </semantics></math> and <math display="inline"><semantics> <mrow> <mi>r</mi> <mo>=</mo> <mn>0.3</mn> </mrow> </semantics></math> with <math display="inline"><semantics> <mrow> <mi>m</mi> <mfenced separators="" open="(" close=")"> <msub> <mi>U</mi> <mi>r</mi> </msub> <mrow> <mo>(</mo> <mi>x</mi> <mo>)</mo> </mrow> </mfenced> <mo>=</mo> <mn>1.7691</mn> </mrow> </semantics></math>.</p>
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<p>Box plots of quality criteria calculated for 100 designs with 50 points in two dimensions.</p>
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<p>Box plots of quality criteria calculated for 100 designs with 50 points in three dimensions.</p>
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16 pages, 644 KiB  
Review
Investigating Menstruation and Adverse Pregnancy Outcomes: Oxymoron or New Frontier? A Narrative Review
by Kirstin Tindal, Fiona L. Cousins, Stacey J. Ellery, Kirsten R. Palmer, Adrienne Gordon, Caitlin E. Filby, Caroline E. Gargett, Beverley Vollenhoven and Miranda L. Davies-Tuck
J. Clin. Med. 2024, 13(15), 4430; https://doi.org/10.3390/jcm13154430 - 29 Jul 2024
Cited by 1 | Viewed by 1472
Abstract
Not discounting the important foetal or placental contribution, the endometrium is a key determinant of pregnancy outcomes. Given the inherently linked processes of menstruation, pregnancy and parturition with the endometrium, further understanding of menstruation will help to elucidate the maternal contribution to pregnancy. [...] Read more.
Not discounting the important foetal or placental contribution, the endometrium is a key determinant of pregnancy outcomes. Given the inherently linked processes of menstruation, pregnancy and parturition with the endometrium, further understanding of menstruation will help to elucidate the maternal contribution to pregnancy. Endometrial health can be assessed via menstrual history and menstrual fluid, a cyclically shed, easily and non-invasively accessible biological sample that represents the distinct, heterogeneous composition of the endometrial environment. Menstrual fluid has been applied to the study of endometriosis, unexplained infertility and early pregnancy loss; however, it is yet to be examined regarding adverse pregnancy outcomes. These adverse outcomes, including preeclampsia, foetal growth restriction (FGR), spontaneous preterm birth and perinatal death (stillbirth and neonatal death), lay on a spectrum of severity and are often attributed to placental dysfunction. The source of this placental dysfunction is largely unknown and may be due to underlying endometrial abnormalities or endometrial interactions during placentation. We present existing evidence for the endometrial contribution to adverse pregnancy outcomes and propose that a more comprehensive understanding of menstruation can provide insight into the endometrial environment, offering great potential value as a diagnostic tool to assess pregnancy risk. As yet, this concept has hardly been explored. Full article
(This article belongs to the Special Issue Clinical Risks and Perinatal Outcomes in Pregnancy and Childbirth)
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<p>The potential contribution of factors that contribute to the resultant spectrum of adverse pregnancy outcomes. AUB: abnormal uterine bleeding; RIF: recurrent implantation failure; RPL: recurrent pregnancy loss; FGR: foetal growth restriction.</p>
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16 pages, 313 KiB  
Article
Stability of Queueing Systems with Impatience, Balking and Non-Persistence of Customers
by Alexander N. Dudin, Sergey A. Dudin, Valentina I. Klimenok and Olga S. Dudina
Mathematics 2024, 12(14), 2214; https://doi.org/10.3390/math12142214 - 15 Jul 2024
Cited by 2 | Viewed by 1068
Abstract
The operation of many queueing systems is adequately described by the structured multidimensional continuous-time Markov chains. The most well-studied classes of such chains are level-independent Quasi-Birth-and-Death processes, GI/M/1 type and M/G/1 type Markov chains, [...] Read more.
The operation of many queueing systems is adequately described by the structured multidimensional continuous-time Markov chains. The most well-studied classes of such chains are level-independent Quasi-Birth-and-Death processes, GI/M/1 type and M/G/1 type Markov chains, generators of which have the block tri-diagonal, lower- and upper-Hessenberg structure, respectively. All these classes assume that the matrices of transition rates are quasi-Toeplitz. This property greatly simplifies their analysis but makes them inappropriate for the study of many important systems, e.g., retrial queues with a retrial rate depending on the number of customers in orbit, queues with impatient customers, etc. The importance of such systems attracts significant interest to their analysis. However, in the literature, there is a methodological gap relating to the ergodicity condition of the corresponding Markov chains. To fulfill this gap and facilitate the analysis of a wide range of such systems, we show that under non-restrictive assumptions, the following hold true: (i) if the customers can balk or are impatient or non-persistent, then the Markov chain describing the behavior of the system belongs to the class of asymptotically quasi-Toeplitz Markov chains; (ii) this chain is ergodic; (iii) known algorithms can be applied for the calculation of the stationary distribution of the corresponding queueing system. Full article
(This article belongs to the Special Issue Advances in Queueing Theory and Applications)
60 pages, 6976 KiB  
Review
Reactive Oxygen Species (ROS)-Mediated Antibacterial Oxidative Therapies: Available Methods to Generate ROS and a Novel Option Proposal
by Silvana Alfei, Gian Carlo Schito, Anna Maria Schito and Guendalina Zuccari
Int. J. Mol. Sci. 2024, 25(13), 7182; https://doi.org/10.3390/ijms25137182 - 29 Jun 2024
Cited by 22 | Viewed by 3010
Abstract
The increasing emergence of multidrug-resistant (MDR) pathogens causes difficult-to-treat infections with long-term hospitalizations and a high incidence of death, thus representing a global public health problem. To manage MDR bacteria bugs, new antimicrobial strategies are necessary, and their introduction in practice is a [...] Read more.
The increasing emergence of multidrug-resistant (MDR) pathogens causes difficult-to-treat infections with long-term hospitalizations and a high incidence of death, thus representing a global public health problem. To manage MDR bacteria bugs, new antimicrobial strategies are necessary, and their introduction in practice is a daily challenge for scientists in the field. An extensively studied approach to treating MDR infections consists of inducing high levels of reactive oxygen species (ROS) by several methods. Although further clinical investigations are mandatory on the possible toxic effects of ROS on mammalian cells, clinical evaluations are extremely promising, and their topical use to treat infected wounds and ulcers, also in presence of biofilm, is already clinically approved. Biochar (BC) is a carbonaceous material obtained by pyrolysis of different vegetable and animal biomass feedstocks at 200–1000 °C in the limited presence of O2. Recently, it has been demonstrated that BC’s capability of removing organic and inorganic xenobiotics is mainly due to the presence of persistent free radicals (PFRs), which can activate oxygen, H2O2, or persulfate in the presence or absence of transition metals by electron transfer, thus generating ROS, which in turn degrade pollutants by advanced oxidation processes (AOPs). In this context, the antibacterial effects of BC-containing PFRs have been demonstrated by some authors against Escherichia coli and Staphylococcus aureus, thus giving birth to our idea of the possible use of BC-derived PFRs as a novel method capable of inducing ROS generation for antimicrobial oxidative therapy. Here, the general aspects concerning ROS physiological and pathological production and regulation and the mechanism by which they could exert antimicrobial effects have been reviewed. The methods currently adopted to induce ROS production for antimicrobial oxidative therapy have been discussed. Finally, for the first time, BC-related PFRs have been proposed as a new source of ROS for antimicrobial therapy via AOPs. Full article
(This article belongs to the Special Issue New Types of Antimicrobial Biocides)
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Graphical abstract

Graphical abstract
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<p>Schematic pathways of reactive oxygen species (ROS) production and their main effects on biological systems. Nrf2 = erythroid nuclear transcription factor-2; NF-kB = transcription factor involved in cellular responses to stimuli such as stress, cytokines, free radicals, heavy metals, ultraviolet irradiation, oxidized low-density lipoproteins (LDL), etc. Reproduced from our article [<a href="#B11-ijms-25-07182" class="html-bibr">11</a>].</p>
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<p>ROS induction by antibiotics as a secondary mechanism of their antibacterial effects.</p>
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<p>Jablonski diagram showing the photochemical and photophysical mechanisms of antimicrobial photodynamic therapy (PDT). S<sub>0</sub>: ground singlet state of the PS molecule; Sn: excited singlet state of the PS molecule; T<sub>1</sub>: triplet excited state of the PS molecule; A: absorption of light; F: fluorescence emission; H: heat generation (internal conversion); ISC: inter-system crossing; P: phosphorescence emission; <sup>3</sup>O<sub>2</sub>: ground state oxygen; <sup>1</sup>O<sub>2</sub>: singlet oxygen; O<sup>2−•</sup>: superoxide anion; HO•: hydroxyl radical; H<sub>2</sub>O<sub>2</sub>: hydrogen peroxide. The image is an adaptation from an Open Access article distributed under the terms of the Creative Commons Attribution License (<a href="http://creativecommons.org/Licenses/by/4.0/" target="_blank">http://creativecommons.org/Licenses/by/4.0/</a> accessed on 22 May 2024), which permits unrestricted use, distribution, and reproduction in any medium [<a href="#B86-ijms-25-07182" class="html-bibr">86</a>].</p>
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<p>Characteristics and criteria that a medical-grade honey (MGH) should fulfill, according to Hermann et al. [<a href="#B198-ijms-25-07182" class="html-bibr">198</a>].</p>
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<p>HBOT enhances the immune system’s antimicrobial effects: Increased O<sub>2</sub> levels during HBOT have a variety of biological effects, including suppression of proinflammatory mediators, transitory reduction in the CD4:CD8 T cell ratio, and stimulation of lymphocyte and neutrophil death through caspase-3-, caspase-7-, and caspase-9-dependent mechanisms. In general, these effects can boost the antibacterial processes of the immune system and infection recovery. Abbreviations: ROS, reactive oxygen species; IL, interleukin; INF, interferon; TNF, tumor necrosis factor; CAS, caspase; NO, nitric oxide. Licensee: MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (<a href="https://creativecommons.org/licenses/by/4.0/" target="_blank">https://creativecommons.org/licenses/by/4.0/</a> accessed on 22 May 2024) [<a href="#B240-ijms-25-07182" class="html-bibr">240</a>].</p>
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<p>Events caused by hyperbaric oxygen therapy and the mechanisms by which its antibacterial effects derive.</p>
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<p>Number of publications on BCs-derived PFRs from 2014 according to the Scopus dataset (reviews and chapters in books included). The survey used the following keywords: persistent AND free AND radicals AND biochar [<a href="#B24-ijms-25-07182" class="html-bibr">24</a>].</p>
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<p>Possible mechanisms leading to the formation of BC-bounded PFRs from lignin. The orange sphere represents biomass, while the black sphere represents BC, whose hypothetic structures depending on the pyrolysis condition have been shown at the bottom of the scheme [<a href="#B24-ijms-25-07182" class="html-bibr">24</a>].</p>
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<p>Possible mechanisms leading to the formation of BC-bounded graphitic PFRs from cellulose (left side) and emicellulose (right side). The orange sphere represents biomass, while the black sphere represents BC, whose hypothetic structures depending on the pyrolysis condition have been shown at the bottom of the scheme [<a href="#B24-ijms-25-07182" class="html-bibr">24</a>].</p>
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16 pages, 3379 KiB  
Article
Feasibility Analysis of ECG-Based pH Estimation for Asphyxia Detection in Neonates
by Nadia Muhammad Hussain, Bilal Amin, Barry James McDermott, Eoghan Dunne, Martin O’Halloran and Adnan Elahi
Sensors 2024, 24(11), 3357; https://doi.org/10.3390/s24113357 - 24 May 2024
Cited by 1 | Viewed by 1100
Abstract
Birth asphyxia is a potential cause of death that is also associated with acute and chronic morbidities. The traditional and immediate approach for monitoring birth asphyxia (i.e., arterial blood gas analysis) is highly invasive and intermittent. Additionally, alternative noninvasive approaches such as pulse [...] Read more.
Birth asphyxia is a potential cause of death that is also associated with acute and chronic morbidities. The traditional and immediate approach for monitoring birth asphyxia (i.e., arterial blood gas analysis) is highly invasive and intermittent. Additionally, alternative noninvasive approaches such as pulse oximeters can be problematic, due to the possibility of false and erroneous measurements. Therefore, further research is needed to explore alternative noninvasive and accurate monitoring methods for asphyxiated neonates. This study aims to investigate the prominent ECG features based on pH estimation that could potentially be used to explore the noninvasive, accurate, and continuous monitoring of asphyxiated neonates. The dataset used contained 274 segments of ECG and pH values recorded simultaneously. After preprocessing the data, principal component analysis and the Pan–Tompkins algorithm were used for each segment to determine the most significant ECG cycle and to compute the ECG features. Descriptive statistics were performed to describe the main properties of the processed dataset. A Kruskal–Wallis nonparametric test was then used to analyze differences between the asphyxiated and non-asphyxiated groups. Finally, a Dunn–Šidák post hoc test was used for individual comparison among the mean ranks of all groups. The findings of this study showed that ECG features (T/QRS, T Amplitude, Tslope, Tslope/T, Tslope/|T|, HR, QT, and QTc) based on pH estimation differed significantly (p < 0.05) in asphyxiated neonates. All these key ECG features were also found to be significantly different between the two groups. Full article
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<p>Preprocessing steps performed in this work: (<b>a</b>) Raw ECG signal; (<b>b</b>) BL-Removed: ECG signal after baseline (BL) noise removal; (<b>c</b>) HF-Removed: ECG signal after high-frequency (HF) noise removal; (<b>d</b>) ECG PLI-Removed: ECG signal after power-line interference (PLI) removal; (<b>e</b>) Normalized or preprocessed ECG signal.</p>
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<p>QRS-peak detection. On the ECG segment displayed in blue color, the red asterisk (<span style="color:red">⁕</span>) represents the detected Q-wave peak position, the green asterisk (<span style="color:#67ef03">⁕</span>) denotes the R-wave peak position, and the black asterisk (⁕) indicates the S-wave peak position.</p>
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<p>Flow chart of the ECG feature extraction used in this work. The process resulted in the features to be used for ECG statistical analysis.</p>
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<p>ECG segments vs. pH value.</p>
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<p>Descriptive analysis using box plots for the neonate’s group (acidosis, normal, alkalosis) represents the mean values (green diamond-shaped markers) and the median values (red dots) of the ECG features. These box plots and whisker plots illustrate that the data are not symmetrical, and the mean values are not equal to the median values around the median, suggesting that the data are not normalized.</p>
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<p>Interactive graphs illustrate the pairwise comparison of the estimates and comparison intervals to display the significant difference among all three groups (acidosis, normal, and alkalosis). The group means are along the x-axis, and the groups are categorized along the y-axis. The red intervals and estimates depict that the selected group is significantly different from others (blue intervals). Groups that do not have significantly different means to the normal group are displayed in black color.</p>
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