Articles de revues : « Twin basins »

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Wu, Xiaotao, Guihua Lu et Zhiyong Wu. « Remote Sensing Technology in the Construction of Digital Twin Basins : Applications and Prospects ». Water 15, n^o 11 (27 mai 2023) : 2040. http://dx.doi.org/10.3390/w15112040.

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A digital twin basin serves as a virtual representation of a physical basin, enabling synchronous simulation, virtual–real interaction, and iterative optimization. The construction of a digital twin basin requires a basin database characterized by large-scale coverage, high-precision, high-resolution, and low-latency attributes. The advancements in remote sensing technology present a new technical means for acquiring essential variables of the basin. The purpose of this paper was to provide a comprehensive overview and discussion of the retrieval principle, data status, evaluation and inter-comparison, advantages and challenges, applications, and prospects of remote sensing technology in capturing seven essential variables, i.e., precipitation, surface temperature, evapotranspiration, water level, river discharge, soil moisture, and vegetation. It is indicated that remote sensing can be applied in some digital twin basin functions, such as drought monitoring, precipitation forecasting, and water resources management. However, more effort should be paid to improve the data accuracy, spatiotemporal resolution, and latency through data merging, data assimilation, bias correction, machine learning algorithms, and multi-sensor joint retrieval. This paper will assist in advancing the application of remote sensing technology in constructing a digital twin basin.

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Yang, Fangyan, Yongming Cao, Lijuan Chen et Qingdu Li. « Sequence of Routes to Chaos in a Lorenz-Type System ». Discrete Dynamics in Nature and Society 2020 (23 janvier 2020) : 1–10. http://dx.doi.org/10.1155/2020/3162170.

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This paper reports a new bifurcation pattern observed in a Lorenz-type system. The pattern is composed of a main bifurcation route to chaos (n=1) and a sequence of sub-bifurcation routes with n=3,4,5,…,14 isolated sub-branches to chaos. When n is odd, the n isolated sub-branches are from a period-n limit cycle, followed by twin period-n limit cycles via a pitchfork bifurcation, twin chaotic attractors via period-doubling bifurcations, and a symmetric chaotic attractor via boundary crisis. When n is even, the n isolated sub-branches are from twin period-n/2 limit cycles, which become twin chaotic attractors via period-doubling bifurcations. The paper also shows that the main route and the sub-routes can coexist peacefully by studying basins of attraction.

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Henriksen, Hans Jørgen, Raphael Schneider, Julian Koch, Maria Ondracek, Lars Troldborg, Ida K. Seidenfaden, Søren Julsgaard Kragh, Eva Bøgh et Simon Stisen. « A New Digital Twin for Climate Change Adaptation, Water Management, and Disaster Risk Reduction (HIP Digital Twin) ». Water 15, n^o 1 (21 décembre 2022) : 25. http://dx.doi.org/10.3390/w15010025.

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The paper analyzes the national DK-model hydrological information and prediction (HIP) system and HIP portal viewed as a ‘digital twin’ and how the introduction of real-time dynamic updating of the DK-model HIP simulations can make room for plug-in submodels with real-time boundary conditions made available from an HIP portal. The possible feedback to a national real-time risk knowledge base during extreme events (flooding and drought) is also discussed. Under climate change conditions, Denmark is likely to experience more rain in winter, more evapotranspiration in summer, intensified cloudbursts, drought, and sea level rise. These challenges were addressed as part of the Joint Governmental Digitalization Strategy 2016–2020 for better use and sharing of public data about the terrain, water, and climate to support climate adaptation, water management, and disaster risk reduction. This initiative included the development of a new web-based data portal (HIP portal) developed by the Danish Agency for Data Supply and Infrastructure (SDFI). GEUS delivered 5 terabytes of hydrological model data to the portal, with robust calibration methods and hybrid machine learning (ML) being key parts of the deliverables. This paper discusses the challenges and potentials of further developing the HIP digital twin with ‘plug-in digital twins’ for local river basins, including feedback to the national level.

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KATZ, ANDREW L., et EARL H. DOWELL. « FROM SINGLE WELL CHAOS TO CROSS WELL CHAOS : A DETAILED EXPLANATION IN TERMS OF MANIFOLD INTERSECTIONS ». International Journal of Bifurcation and Chaos 04, n^o 04 (août 1994) : 933–41. http://dx.doi.org/10.1142/s0218127494000666.

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The study of stable and unstable manifolds, and their intersections with each other, is a powerful technique for interpreting complex bifurcations of nonlinear systems. The escape phenomenon in the twin-well Duffing oscillator is one such bifurcation that is elucidated through the analysis of manifold intersections. In this paper, two escape scenarios in the twin-well Duffing oscillator are presented. In each scenario, the relevant manifold structures are examined for parameter values on either side of the escape bifurcation. Included is a description of the role of the hilltop saddle stable manifolds, which are known to separate the single well basins (should single well attractors exist). In each of the two bifurcation scenarios, it is shown through a detailed analysis of Poincaré maps that a homoclinic intersection of the manifolds of a specific period-3 saddle implies the destruction of the single well chaotic attractor. Although the Duffing oscillator is used to illustrate the ideas advanced here, it is thought that the approach will be useful for a variety of dynamical systems.

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Todd, M. D., et L. N. Virgin. « An Experimental Verification of Basin Metamorphoses in A Nonlinear Mechanical System ». International Journal of Bifurcation and Chaos 07, n^o 06 (juin 1997) : 1337–57. http://dx.doi.org/10.1142/s0218127497001060.

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This paper describes bifurcations and the basin boundary metamorphoses that give rise to post-fold outcome indeterminacy from a primarily experimental perspective. A gravity-loaded cart-and-track system is constrained to mimic the twin-well, single-degree-of-freedom Duffing oscillator. Of primary interest is the study of how motion, initially contained within a single well, "spills over" into the adjacent well. Although this system is globally bounded, it retains the same generic features of the single-well canonical escape equation. Using time-embedded coordinates, the technique of stochastic interrogation is used to generate the initial condition maps at three different forcing levels corresponding to three different regimes of post-fold outcomes. These three regions are characterized, respectively, by smooth basin boundaries with safe jumps to resonance, fractal basin boundaries with jumps that may or may not restabilize on to the resonant attractor, and eroded basins with unsafe jumps leading to escape from the local well. This experiment successfully replicates much of the subtle global behavior observed in numerical simulations.

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Mottier, V., F. Brissaud, P. Nieto et Z. Alamy. « Wastewater treatment by infiltration percolation : a case study ». Water Science and Technology 41, n^o 1 (1 janvier 2000) : 77–84. http://dx.doi.org/10.2166/wst.2000.0014.

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A 1700 p.e. pilot infiltration percolation plant treating the sewage of Mazagon, a seaside resort in the South of Spain, is investigated. Primary effluents, intermittently applied over twin 200 m2 infiltration basins, percolate down to the aquifer through unsaturated dune sands. Each application sequence delivers a volume of 0.25 m3 per m2 of infiltration basin. Analyses of the water sampled at five depths ranging from 0.3 to 2.0 m below the infiltration surface show that the oxidation performance of the plant is highly dependent on the applied load. Monitoring the oxygen content in the air phase of the vadose zone allows to determine the kinetics of the oxygen stock recovery and the oxidation capacity of the plant. Disappointing removal of faecal coliforms and streptococci is attributed to high pore water velocities due to infiltration heterogeneity and the high water height applied during each feeding sequence.

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Szemplińska-Stupnicka, W., et E. Tyrkiel. « Sequences of Global Bifurcations and the Related Outcomes after Crisis of the Resonant Attractor in a Nonlinear Oscillator ». International Journal of Bifurcation and Chaos 07, n^o 11 (novembre 1997) : 2437–57. http://dx.doi.org/10.1142/s0218127497001631.

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The problem of the system behavior after annihilation of the resonant attractor in the region of the nonlinear resonance hysteresis is considered. The sequences of global bifurcations, in connection with the associated metamorphoses of basins of attraction of coexisting attractors, are examined. The study allows one to reveal the mechanism that governs the phenomenon of the post crisis ensuing transient trajectory to settle onto one or another remote attractor. The problem is studied in detail for the twin-well potential Duffing oscillator. The boundary which splits the considered region of system parameters into two subdomains, where the outcome is unique or the two outcomes are possible, is defined.

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Szemplińska-Stupnicka, Wanda, et Krzysztof L. Janicki. « Basin Boundary Bifurcations and Boundary Crisis in the Twin-Well Duffing Oscillator : Scenarios Related to the Saddle of the Large Resonant Orbit ». International Journal of Bifurcation and Chaos 07, n^o 01 (janvier 1997) : 129–46. http://dx.doi.org/10.1142/s0218127497000091.

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Bifurcation phenomena in the twin-well Duffing system are considered for such regions of the system parameters, where the saddle DL associated with the two-well T-periodic attractor (large orbit) undergoes homoclinic bifurcation. In particular, a co-dimension-two bifurcation, the bifurcation defined by the intersection of the homoclinic bifurcation of the large orbit with the saddle-node bifurcation of the nonresonant single-well orbit in the system parameter plane is the main point of interest. In the four subdomains around the co-dimension-two point, the manifold structure of the saddle DL and the basins of attractions are studied numerically. The analysis reveals new phenomena and new features of the system behavior. A complex bifurcational structure is observed that includes boundary crisis of the cross-well chaotic attractor, intermittency (subduction) phenomena, and explosion of the basin of attraction of the large orbit. The analysis also explains why, in one of the subdomains, the two-well T-periodic attractor (large orbit) becomes the unique attractor of the system.

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Nath, Rupak, et S. Kharbuli. « Cyprinid Fishes : An Overview on the Present Status in Meghalaya, India ». Spectrum : Science and Technology 7, n^o 1 (15 décembre 2020) : 13–22. http://dx.doi.org/10.54290/spect/2020.v7.1.0002.

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Cyprinid fishes of Meghalaya were investigated from twin drainage basins Brahmaputra and Barak-Surma-Meghna. 27 cyprinid fishes under 14 genus and 7 sub families were recorded from rivers and reservoirs of four different gradient zones. The diversity of Cyprinid fishes was highest with 49% representation of Cyprinids at lower elevation Zone IV below 500 m above MSL and bio diversity indices estimated as H: 3.05, 1-D: 0.10. In contrary lowest diversity with 7% representation of fishes was observed at elevation 1501 to 2000 m above MSL in Zone I with bio diversity indices H: 0.25, 1-D: 0.57. Distribution of commercially important cyprinids under genus Labeo, Systomus and Cirrhinus were found to be restricted to rivers of Barak-Surma-Meghna drainage basin. Catch percentage of cyprinids indicates that 70% of fishes exhibit occasional occurrence and 30% as common occurrence. High percentage of occasional occurrence, low catch composition percentage and with restricted distribution of commercially important fishes to only certain rivers of Barak-Surma-Meghna drainage is an indication of depletion of cyprinid resources in the state and requires taking multi prong conservation measures to protect cyprinid fishes in Meghalaya.

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Rao, Xiaokang, Rui Ma, Li Zhang et Jia Liu. « Research and design of a digital twin-driven smart river basin platform ». Metaverse 3, n^o 2 (26 juillet 2022) : 11. http://dx.doi.org/10.54517/m.v3i2.1815.

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River basin management involves many issues including water resources, water ecology, water environment, and water disasters. Digital twins integrated with GIS, BIM and IoT are applied to river basin management, to establish digital twin data and model integration and visual expression methods, study the digital twin operation mechanism, build smart river basin twin, and design a digital twin-driven smart river basin platform. Taking the joint flood dispatching management and control of the reservoir group in the Duhe River Basin as an example. The application has proven that: compared with the problems of incomplete information, insufficient accuracy, lagging feedback and single expression in traditional basin database management or two-dimensional plane management, the digital twin-driven smart basin platform, on the basis of the integration and interaction of GIS data, BIM data and IoT data, and on the basis of data and model two-way drive, can realize simulation, decision making, optimization and visualization in external environment, and the control effect is better than traditional means. The research and practice of the platform can realize real-time monitoring, diagnosis, analysis, decision making and prediction for river basin management, providing a new solution for its intelligent operation, precise control and safe operation and maintenance.

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Rao, Xiaokang, Rui Ma, Li Zhang et Jia Liu. « Research and design of a digital twin-driven smart river basin platform ». Metaverse 3, n^o 2 (26 juillet 2022) : 11. http://dx.doi.org/10.54517/met.v3i2.1815.

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River basin management involves many issues including water resources, water ecology, water environment, and water disasters. Digital twins integrated with GIS, BIM and IoT are applied to river basin management, to establish digital twin data and model integration and visual expression methods, study the digital twin operation mechanism, build smart river basin twin, and design a digital twin-driven smart river basin platform. Taking the joint flood dispatching management and control of the reservoir group in the Duhe River Basin as an example. The application has proven that: compared with the problems of incomplete information, insufficient accuracy, lagging feedback and single expression in traditional basin database management or two-dimensional plane management, the digital twin-driven smart basin platform, on the basis of the integration and interaction of GIS data, BIM data and IoT data, and on the basis of data and model two-way drive, can realize simulation, decision making, optimization and visualization in external environment, and the control effect is better than traditional means. The research and practice of the platform can realize real-time monitoring, diagnosis, analysis, decision making and prediction for river basin management, providing a new solution for its intelligent operation, precise control and safe operation and maintenance.

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Imaizumi, Yoko, et Kazuo Hayakawa. « Infant Mortality Among Singletons and Twins in Japan During 1999–2008 on the Basis of Risk Factors ». Twin Research and Human Genetics 16, n^o 2 (29 janvier 2013) : 639–44. http://dx.doi.org/10.1017/thg.2012.156.

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The infant mortality rate (IMR) among single and twin births from 1999 to 2008 was analyzed using Japanese Vital Statistics. The IMR was 5.3-fold higher in twins than in singletons in 1999 and decreased to 3.9-fold in 2008. The reduced risk of infant mortality in twins relative to singletons may be related, partially, to survival rates, which improved after fetoscopic laser photocoagulation for twin — twin transfusion syndrome. The proportion of neonatal deaths among total infant deaths was 54% for singletons and 74% for twins. Thus, intensive care of single and twin births may be very important during the first month of life to reduce the IMR. The IMR decreased as gestational age (GA) rose in singletons, whereas the IMR in twins decreased as GA rose until 37 weeks and increased thereafter. The IMR was significantly higher in twins than in singletons from the shortest GA (<24 weeks) to 28 weeks as well as ≥38 weeks, whereas the IMR was significantly higher in singletons than in twins from 30 to 36 weeks. As for maternal age, the early neonatal and neonatal mortality rates as well as the IMR in singletons were significantly higher in the youngest maternal age group than in the oldest one, whereas the opposite result was obtained in twins. The lowest IMR in singletons was 1.1 per 1,000 live births for ≥38 weeks of gestation and heaviest birth weight (≥2,000 g), while the lowest IMR in twins was 1.8 at 37 weeks and ≥2,000 g.

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Demir, Ayse Banu, et Namik Demir. « Epigenetic Basis of Twin Discordance in Diseases : Future Benefits ». Gynecology Obstetrics & ; Reproductive Medicine 24, n^o 2 (10 août 2018) : 108. http://dx.doi.org/10.21613/gorm.2017.741.

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Monozygotic twins share the same genotype since they are derived from the same zygote. However, monozygotic (MZ) twin siblings frequently present many phenotypic differences, such as their susceptibilities to diseases. These isogenic individuals are not entirely identical. They exhibit phenotypic incompatibility for many features, from birth weight to complex diseases. Recently, several studies have been published showing that phenotypic differences, especially in MZ twins, are being induced from prenatal period to life-long epigenetic differences. Epigenetic studies on twins have a great potential to contribute to our understanding of complex diseases, such as cancer, autoimmune disorders, psychiatric disorders and neurological diseases. Since MZ twins are genetic clones (genetically identical), they are considered as perfect models for studying the role of environmental factors as determinants of complex diseases and phenotypes. In this review, a number of intrauterine effects and genetic mechanisms that may affect phenotypic, genotypic, and epigenetic differences between MZ twins were described and effects of epigenetic mechanisms on complex diseases were mentioned. Further work on epigenetic changes in diseases using incompatible MZ twin models, would lead to new developments in medical therapies.

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Spacca, Barbara, et Neil Buxton. « Spina bifida occulta and monozygotic twins ». Journal of Neurosurgery : Pediatrics 2, n^o 4 (octobre 2008) : 258–60. http://dx.doi.org/10.3171/ped.2008.2.10.258.

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Central nervous system maldevelopment can have different presentations in twins. We report on a case of different presentations of spina bifida occulta in monozygotic twins. The first twin presented at birth with a lipomyelomeningocele; a tethered cord was diagnosed in the second twin at 2 years of age. Neural tube defects (NTDs) are a group of common congenital malformations of the brain and spine generated during neurulation. The genetic basis of this process is still not well known. Whenever an NTD is diagnosed in one of a pair of twins, the other twin should also be evaluated for NTDs.

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Semin, Alexander, Denis Mironov, Mikhail Kislitskiy, Alexander Zasypkin et Valery Ivanov. « Improving the Theoretical and Methodological Framework for Implementing Digital Twin Technology in Various Sectors of Agriculture ». Emerging Science Journal 7, n^o 4 (12 juillet 2023) : 1100–1115. http://dx.doi.org/10.28991/esj-2023-07-04-05.

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The aim of this study is to systematize and improve the theoretical and methodological framework for implementing digital twin technology. The study focuses on digital twins in agriculture. This paper is designed to solve the scientific problem associated with the development of a methodological framework for the implementation of digital twins in the work of agricultural organizations. Using methods of analysis of socio-economic phenomena and processes on the basis of a set of scientific approaches, economic-statistical analysis, and others, the study considers the importance of digital twins of agricultural machinery and equipment, identifies trends in agriculture determined by digitalization, and suggests promising areas for digital twins of agricultural machinery and equipment. This paper also examines the theoretical basis for the implementation of digital twin technology in the agricultural sector of production. New research results complement the theoretical provisions on the essence of digital twin technology; develop the methodological provisions of digital twin technology, represented by the study of their significance, principles, and features of operation. The study may be seen as academically novel as it reveals the prerequisites for implementing digital technology in agriculture as well as clarifies and improves the theoretical and methodological provisions of the application of digital twin technology in various sectors of agriculture.

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Webbink, Dinand, Jaap Roeleveld et Peter M. Visscher. « Identification of Twin Pairs From Large Population-Based Samples ». Twin Research and Human Genetics 9, n^o 4 (1 août 2006) : 496–500. http://dx.doi.org/10.1375/twin.9.4.496.

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AbstractThe basis of most twin studies is the ascertainment of twins, often through twin registries, and determination of zygosity. The current rate of twin births in many industrialized countries implies that in the near future around 3% or more of individuals will be a twin. Hence, there are and will be a lot of twins around and many of those will not participate in twin studies. However, if large population-based samples are available that include appropriate identifiers, then twins can be detected and twin studies performed, even in the absence of zygosity information. We quantified the number of twin pairs that could be detected from a longitudinal survey in the Netherlands, which aims to answer questions about educational strategies and performance in primary education in the Netherlands. We detected 2865 twin pairs if we used a coded name identifier, date of birth, school, grade and year of survey, which is 2.01% of 284,945 pupils in five cohorts. Relaxing our selection criteria increased the number of apparent twin pairs identified, most of which are false positives due to chance matching of identification criteria. We show that the intraclass correlation on measured phenotypes can be used as a quality control measure for twin identification, and quantify the proportion of false negatives (true twin pairs not identified) due to missing data and data coding errors. We compared our estimated rate of twins in the sample to census data and estimate that with our most stringent selection criteria we detect more than 80% of all twin pairs in the sample. We conclude that the identification of twin pairs from large population-based samples is feasible, rapid and accurate if the appropriate identifiers are available, and that twin pairs from such sources are a valuable resource for studies to answer scientific question about twins versus nontwins and about genetic and environmental factors of twin resemblance.

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Barham, Henry P., Justin M. Wudel, Robert W. Enzenauer et Kenny H. Chan. « Congenital Nasolacrimal Duct Cyst/Dacryocystocele : An Argument for a Genetic Basis ». Allergy & ; Rhinology 3, n^o 1 (janvier 2012) : ar.2012.3.0024. http://dx.doi.org/10.2500/ar.2012.3.0024.

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Embryogenesis of a congenital nasolacrimal duct (NLD) cyst is attributed to the failure of the Hasner membrane of the NLD system to cannulate. Prenatal diagnosis of congenital NLD cysts supports the argument for a developmental error, with a postnatal prevalence of 6%. The role of a genetic basis for this malformation has never been ascribed. We present a set of monozygotic twins with bilateral congenital NLD cysts as an argument for a genetic basis of this entity. A case report and literature review were performed. We present two cases of bilateral congenital NLD cysts occurring in a set of monozygotic twins. Patients were delivered at 37 weeks via cesarean section. The pregnancy was complicated by preterm labor at 33 weeks requiring administration of terbutaline and betamethasone. At presentation, twin A had bilateral eye discharge, erythema, and swelling medial to the medial canthi as well as nasal obstruction. Computed tomography (CT) showed classic bilateral cystic masses in the inferior meatus. The diagnosis of bilateral infected congenital dacryocystoceles was made. Twin B initially presented with only bilateral eye discharge and CT showed a dilated NLD system. Twin B subsequently developed early signs of bilateral dacryocystoceles the following day. Both patients underwent lacrimal probing and endoscopic marsupialization of the dacryocystoceles. Biopsies were consistent with dacryocystocele. Dacryocystocele is a common presentation of unresolved neonatal NLD obstruction. This case report in a set of identical twins is an argument for a genetic basis for the formation of this lesion.

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Meric, Engin, Niyazi Avsar, Mehmet Baki Yokes et Feyza Dincer. « Atlas of Recent Benthic foraminifera from Turkey ». Micropaleontology 60, n^o 3-4 (2014) : 211–398. http://dx.doi.org/10.47894/mpal.60.3.01.

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Benthic foraminifera are single-celled organisms abundantly found in all kind of marine environments from brackish estuaries to the deep ocean basins at all latitudes. Foraminifera are covered with an organic test which accumulate in the sediment and make up a significant amount of sedimentary rock. Many species have well defined salinity and temperature preferences making them particularly useful for reconstructing ecological changes occured in the past. The fossil tests not only used for paleoenvironmental interpretition, but also for biostratigraphy and age-dating. Anthropogenic pollution or environmental factors may cuase abnormal development of the test, such as aberrant chamber shape and size, twisted or distorted chamber arrangement, multiple apertures, twin, triplet and even quadruplet forms. These abnormalities are commonly used as indicators of pollution. Many researchers have studied the recent benthic and planktic foraminifera of the Mediterranean fauna. The studies have investigated the distribution and abundance of the species, composition of the foraminiferal assemblages, ecological factors and interractions of tests with the substrate. Recent studies, mainly focused on the alien species and their ecological impact. Despite the numerous researches, there is a lack of a comprehensive illustrated guide to the Mediterranean foraminifeal fauna, except the “Mediterranean Foraminifera” (Cimerman and Langer 1991), which included samples from Adriatic and Tyrrhenian Seas, representing mostly the western Mediterranean fauna. With the presented SEM photos of 299 species in 84 plates, the aim of the present Atlas is to fill the gap and provide an updated checklist of foraminiferal fauna of the Turkish coastline, representing the majority of the Levantine Basin.

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Machin, G. A. « Definitive Methods of Zygosity Determination in Twins : Relevance to Problems in the Biology of Twinning ». Acta geneticae medicae et gemellologiae : twin research 39, n^o 4 (janvier 1990) : 459–71. http://dx.doi.org/10.1017/s0001566000003688.

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AbstractMany studies of embryogenesis and fate of twin pregnancies are invalidated because zygosity is not determined definitively, or is assumed on the basis of inadequate criteria. This paper briefly reviews methods of zygosity determination. It reports published results and a new series of twins in which zygosity was determined by DNA fingerprinting. Implications for methods of prenatal diagnosis of zygosity are discussed in the context of the occasional need for intervention in twin transfusion syndrome or in twins discordant for major malformations. Definitive zygosity and placental anatomy (number of chorions and amnions) is discussed as the firm substrate for studies of normal and abnormal twin development.

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Kunin, V. A., et I. E. Ryskov. « The concept of increasing the efficiency of financial risk management based on the application of new digital technologies ». Economics and Management 30, n^o 1 (12 février 2024) : 80–96. http://dx.doi.org/10.35854/1998-1627-2024-1-80-96.

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Aim. Development of the author’s concept of increasing the efficiency of financial risk management on the basis of application of the technology of creating and using the digital twin of the enterprise.Objectives. To formalize the problems of existing approaches to solving the problems of financial risk management of enterprises of the real sector of economy; to identify trends in the development of digital twins, to formulate the advantages of their practical application and to give the author’s interpretation of the concept of “digital twin of the enterprise”; to build and substantiate a multilayer system of indicators of the digital twin of the enterprise in the context of improving the efficiency of financial risk management; to develop the principles of building a digital twin of the enterprise, focused on solving the problems of financial risk management.Methods. The research was carried out on the basis of system approach, in the process of realization of which the methods of synthesis, logical comparative, factor and graphical analysis, basic provisions of financial risk management and the results obtained in domestic and foreign scientific literature on the problems of realization of approaches and methods of financial risk management were used.Results. The author’s concept of increasing the efficiency of financial risk management based on the application of new technologies for creating digital twins is proposed. In particular, by means of formalizing the problems of existing approaches to solving the problems of financial management, identifying trends in the development of methodology and technologies for creating digital twins, the idea of increasing the efficiency of financial risk management on the basis of creating a digital twin of the enterprise is outlined. The multilayer system of indicators defining the structure of this digital twin is proposed and substantiated, the tasks are defined and the principles of its construction oriented to solving the tasks of financial risk management are developed. The financial kernel of the digital twin of the enterprise is constructed, containing the contours of formation of financial indicators common for different enterprises, determining the achievement of the objectives of financial risk management and its efficiency. The qualitative substantiation of increasing the efficiency of financial risk management with the application of the methodological basis for the creation and use of digital twins proposed in the article is given.Conclusions. Conceptual provisions of creation and use of digital twins for the purposes of financial risk-management, given in the article, create a theoretical and methodological basis for increasing the efficiency of financial risk-management taking into account the use of new digital technologies and can serve as a basis for practical construction of effective systems of financial risk-management at enterprises of the real sector of economy.

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Loos, Ruth, Catherine Derom, Robert Vlietinck et Robert Derom. « The East Flanders Prospective Twin Survey (Belgium) : a population-based registe ». Twin Research 1, n^o 4 (1 août 1998) : 167–75. http://dx.doi.org/10.1375/twin.1.4.167.

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AbstractThe East Flanders Prospective Twin Survey (EFPTS), started in 1964, is unique among the 17 major European twin registers because it is population based, the twins (and higher order births) are ascertained at birth, basic perinatal data are collected, chorion type is established and, when appropriate, genetic markers including DNA fingerprints, are determined. The total number of sets is 5089 twin, 158 triplet and 14 of higher order. Zygosity has been diagnosed on the basis of sex, placental structure and genetic markers in more than 95% of pairs. The EFPTS is the only large register that includes placental data and allows differentiation of three subtypes of monozygotic twins based on the time of the initial zygotic division: the dichorionic—diamnionic pairs (early), the monochorionic—diamnionic pairs (intermediate), and the monochorionic—monoamnionic pairs (late). Methodology and basic results in twins are considered in this article; detailed studies will be reported later. The sex proportion in dizygotic (DZ) twins is the same as in singletons, whereas monozygotic (MZ) twins number more girls than boys. The difference in perinatal mortality between DZ and MZ twins is limited to the monochorionic MZ subgroup. Birth weight is highest in DZ twins and diminishes stepwise in MZ dichorionic and MZ monochorionic twins. Duration of pregnancy follows the same trend but is limited to a few days. Iatrogenic pregnancies are increasing to the point of representing almost 50% of the twin births in 1997.

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Ashwal, Eran, Liran Hiersch, Howard Berger, Amir Aviram, Arthur Zaltz, John Kingdom, Jon Barrett et Nir Melamed. « Pathologic Basis for the Definition of Discordant Growth in Dichorionic Twins ». Fetal Diagnosis and Therapy 48, n^o 4 (2021) : 279–87. http://dx.doi.org/10.1159/000514328.

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Objective: The aim of the current study was to identify the optimal cutoff that should define discordance in dichorionic twin gestations through correlation with abnormal placental pathology as a specific measure of fetal growth restriction of the smaller twin. Methods: We performed a retrospective cohort study of all women with dichorionic twin pregnancies who gave birth in a single center between 2002 and 2015. We investigated the association between the level of growth discordance and maternal vascular malperfusion (MVM) pathology in the placenta of the smaller twin, with and without adjustment for whether the smaller twin is small for gestational age (SGA). Results: A total of 1,198 women with dichorionic twin gestation met the study criteria. The rate of MVM pathology in the placenta of the smaller twin increased with the level of discordance and was most obvious for discordance ≥25% (rate of MVM 12.0% compared with 2.8% in cases with discordance <10%, adjusted relative risk [aRR] 3.71, 95% confidence interval [CI] 1.97–6.99). When the analysis was adjusted for SGA of the smaller twin, discordance was independently associated with MVM pathology only when growth discordance was ≥25% (aRR 2.18, 95%-CI 1.01–4.93), while SGA was strongly associated with MVM pathology irrespective of the level of discordance. Conclusion: Our findings suggest that discordant growth in dichorionic twins should raise the concern of fetal growth restriction of the smaller twin, irrespective of whether the smaller twin is SGA, only when the discordance s ≥25%. The association of lower levels of discordance with abnormal placental pathology is mainly driven by the confounding effect of SGA of the smaller twin.

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Hay, D. A., C. Clifford, P. Derrick, J. Hopper, B. Renard et T. M. Theobald. « Twin Children in Volunteer Registries : Biases in Parental Participation and Reporting ». Acta geneticae medicae et gemellologiae : twin research 39, n^o 1 (janvier 1990) : 71–84. http://dx.doi.org/10.1017/s0001566000005584.

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AbstractThe biases in volutary participation by adult twins are well known but less attention has been paid to twin children where parents decide on participation and provide much of the information. Several aspects of reporting including the assessment of zygosity are compared in four large Australian data bases: 1) a nationwide compulsory (and hence representative) survey of literacy and numeracy; 2) a nationwide “Twins in School” survey of parents and teachers of twins run through Education Departments and AMBA, the parents organisation in conjunction with LaTrobe; 3) the LaTrobe Twin Study which is a longitudinal program involving frequent interactions between families and researchers, and 4) the Australian NHMRC Twin Registry which has surveyed a large sample of their families with twin children by mail. One potential bias comes when recruitment is on a continuing basis as in the LaTrobe Twin Study and the Australian Twin Registry when differences between “early” and “late” enrolling families arise. One difference between the four samples arose from parents being much more likely to contrast their twins and to report problems in one but not the other, whereas teachers' and psychologists' assessments of these same children generally reported much smaller intrapair differences. Future studies should have some common questions to provide comparative data on such biases. Key questions are proposed for this area, mainly on the perceived need for different forms of remediation, together with other recommendations about the minimal essential baseline data set for a registry.

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Sandhyasri, Panda, et S. K. Reshma Begum. « Maternal fetal outcome in multiple versus singleton pregnancies delivered in a teaching hospital ». Indian Journal of Obstetrics and Gynecology Research 9, n^o 1 (15 février 2022) : 54–58. http://dx.doi.org/10.18231/j.ijogr.2022.011.

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To compare the maternal and fetal outcome in multiple versus singleton pregnancies in a private teaching hospital in India. Prospectively collected data on 50 twin deliveries from July 2018 to November 2021 were studied to determine its incidence; the maternal and foetal outcome, and compared with 50 singleton deliveries conducted on same day following the twin delivery who served as controls, the twins were also analysed on the basis of chorionicity. A total of 3415 deliveries were conducted during the study period, of which 50 were twin deliveries, giving an incidence of 14 per 1000 births or 1.4:100 deliveries. Six among 50 twins resulted following ovulation induction. Women with twin gestation had a mean maternal age of 24.7±3.71, same for the singleton mothers was 24.26±3.7years; mean gestational age at delivery for twins and singletons were 35.38±2.6 and 38.63±1.19 weeks; mean birth weight for twins and singletons were 2.193kgs and 2.85±0.46kgs, mean parity were 2.04± 1.0 and 1.72±0.7 respectively. Parity, gestational age, NICU stay characteristics showed p value < 0.05. Compared with singletons, women with twin gestations had a positive risk association with odds >1 for anaemia, preeclampsia, preterm labour, malpresentation and caesarean delivery. Twin Neonates suffered prematurity, low birth weight, congenital anomaly, prolonged NICU care and increased perinatal death. Neonatal risk was more among monochorionic twins than dichorionic twins. There were 3 cases with single fetal demise, and both fetuses IUD in another case, (total IUDs-5), one twin was still born, two had early neonatal death and there were two late neonatal (>7 Days) deaths. One twin mother threw fits on the 6th postpartum day. Another mother received 20 units of blood and component replacement and subtotal hysterectomy for PPH. Despite improvement in antenatal and neonatal care, twins pose a higher threat to MCH outcome. Hence, thorough counselling, patient awareness, more vigilance at interpretation of antenatal tests, intrapartum monitoring and bridging the gap between demand and supply at NICU facility can improve maternal and neonatal outcome; as well as can help parents cope with the psychological stress.

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Spiegler, Juliane, Christoph Härtel, Lena Schulz, Nicole von Wurmb-Schwark, Thomas Hoehn, Angela Kribs, Helmut Küster et al. « Causes of Delivery and Outcomes of Very Preterm Twins Stratified to Zygosity ». Twin Research and Human Genetics 15, n^o 4 (5 juillet 2012) : 532–36. http://dx.doi.org/10.1017/thg.2012.33.

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The increasing rates of preterm birth among twins implicate that solid data on associated risks and outcomes are required. Assessment of zygosity is often based on clinical criteria (evaluation of placenta; same gender, birth weight discordance as surrogate criteria for monochorionic/monozygotic twins). The aim of this study was to compare clinical versus genetic assessment of zygosity and to compare causes of preterm delivery as well as outcome data of very-low-birth-weight (VLBW; birth weight <1,500 g) twins stratified to zygosity. In a multicenter study, we selected n = 176 sets of same gender twins and determined zygosity genetically. In a subgroup of 123 sets of twins, the attending physicians at the study centers were asked to document the parameter ‘zygosity’ (monozygotic/dizygotic) on the basis of their clinical judgment. Concordance between genetic and clinical assessment was 62.7% for monozygotic twins and 88.9% for dizygotic twins, respectively. Outcome parameters (death, BPD, ROP, NEC, IVH) were comparable in both groups. Genetically dizygotic twins were significantly more often born due to intrauterine infection (33% vs. 20% in monozygotic twins, p < .01) and antenatal antibiotics were more frequently given to mothers of dizygotic twins (62% vs. 47% in monozygotic twins, p < .01). Obstetric complications such as twin-twin-transfusion-syndrome were only seen in monozygotic twins as expected. The unexpected increase of antenatal antibiotic treatment and birth due to intrauterine infection in dizygotic twins should be confirmed in additional VLBW twin-cohorts.

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Page, William F., et Linda Corey. « Similarity of social security numbers among twins : data from the Virginia Twin Registry ». Twin Research 1, n^o 3 (1 juin 1998) : 150–53. http://dx.doi.org/10.1375/twin.1.3.150.

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AbstractAt least two twin registries in the United States have been or are being assembled using the similarity of Social Security Numbers in computerized records to help identify possible twin pairs. While the success of such enterprises depends directly on a high probability of twinness given Social Security Numbers, there are theoretical and practical reasons to study the probability of Social Security Number similarity given twinness. For example, the number of twin pairs with similar Social Security Numbers obviously determines the maximum number of twin pairs that can be discovered by similarity algorithms. To study this issue, we examined the similarity of known Social Security Numbers in twin pairs from the Virginia Twin Registry by age, sex, race, and zygosity of the pair. We found that similarity between the Social Security Numbers of twin pairs varies markedly by age, and MZ twin pairs have significantly more similar Social Security Numbers than DZ pairs at all ages. Among older twins, there are also significant differences by sex and race. For younger twins, algorithms that identify putative twin pairs on the basis of the similarity of their Social Security Numbers hold the promise of being able to identify a large proportion of all true twin pairs. Such algorithms will be substantially less successful, however, in identifying a large proportion of older twin pairs.

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Hayakawa, Kazuo, Kenji Kato, Miyuki Onoi, Cai Yang-Ping, Masao Kanamori, Syuichi Doi, Chisato Hayashi, Hiroyuki Kikuchi, Reiko Nishihara et Kensuke Kadota. « The Osaka University Aged Twin Registry : Epigenetics and Identical Twins Discordant for Aging-Dependent Diseases ». Twin Research and Human Genetics 9, n^o 6 (1 décembre 2006) : 808–10. http://dx.doi.org/10.1375/twin.9.6.808.

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AbstractThe Osaka University Aged Twin Registry (OUATR) is the largest adult twin registry in Japan. Since its establishment in 1974, the OUATR has conducted a number of studies with particular focus on the environmental contribution to physical–cognitive–mental aging, longevity and aging-dependent diseases in later adulthood. The registry consists of 12,000 pairs of Japanese twins born between 1900 and 1935. Two hundred and fifty pairs of twins have undergone comprehensive medical examination to date. Follow-up questionnaires have been mailed out on a regular basis, for the purpose of checking current vital statuses, health conditions, and so forth. The main objective of this longitudinal twin study is to contribute to the prevention of lifestyle-related diseases and the promotion of successful aging.

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Cavalieri, Salvatore, et Salvatore Gambadoro. « Proposal of Mapping Digital Twins Definition Language to Open Platform Communications Unified Architecture ». Sensors 23, n^o 4 (20 février 2023) : 2349. http://dx.doi.org/10.3390/s23042349.

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The concept of Digital Twin is of fundamental importance to meet the main requirements of Industry 4.0. Among the standards currently available to realize Digital Twins there is the Digital Twins Definition Language. Digital Twin requires exchange of data with the real system it models and with other applications that use the digital replica of the system. In the context of Industry 4.0, a reference standard for an interoperable exchange of information between applications, is Open Platform Communications Unified Architecture. The authors believe that interoperability between Digital Twins and Open Platform Communications Unified Architectures communication standard should be enabled. For this reason, the main goal of this paper is to allow a Digital Twin based on the Digital Twins Definition Language to exchange data with any applications compliant to the Open Platform Communications Unified Architecture. A proposal about the mapping from Digital Twins Definition Language to the Open Platform Communications Unified Architecture will be presented. In order to verify the feasibility of the proposal, an implementation has been made by the authors, and its description will be introduced in the paper. Furthermore, the main results of the validation process accomplished on the basis of this implementation will be given.

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Laffey-Ardley, Sioban, et Karen Thorpe. « Being Opposite : Is There Advantage for Social Competence and Friendships in Being an Opposite-Sex Twin ? » Twin Research and Human Genetics 9, n^o 1 (1 février 2006) : 131–40. http://dx.doi.org/10.1375/twin.9.1.131.

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AbstractArecent large-scale study of Finnish adolescent twins (Pulkkinen et al., 2003) reported that individuals from opposite-sex twin pairs were more socially adaptive than individuals from same-sex pairs or singletons. This finding raised questions about the social learning effects of being an opposite-sex twin. The current article predicted on the basis of this finding, and evidence from singleton populations, that having an opposite-sex twin would yield social advantage. It sought to examine the social competencies of opposite-sex twins and compare them with same-sex twins and singletons. The study focused on the preschool years (age 3 to 6), a period in which the majority of children encounter their first large group, nonfamilial social experiences. The study obtained reports from parents and teachers of children aged 3 to 6 years: 72 children (36 pairs) who were dizygotic opposite-sex twins (DZOS), 50 children (25 pairs) who were dizygotic same-sex twins (DZSS), and 85 singletons of the same age and sex as the twins, who had at least one sibling. Reports were made using standardized measures of social competencies, behavior problems, language development and friendships. The main effects found were of differences in social competency between twins and singletons. Twins had lower social competency scores. No differences between same-sex and opposite-sex twins were found. The findings did not support the hypothesis of social advantage for opposite-sex twins in early childhood.

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Shultziner, Doron. « Genes and Politics : A New Explanation and Evaluation of Twin Study Results and Association Studies in Political Science ». Political Analysis 21, n^o 3 (2013) : 350–67. http://dx.doi.org/10.1093/pan/mps035.

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This article offers a new explanation for the results of twin studies in political science that supposedly disclose a genetic basis for political traits. I argue that identical twins tend to be more alike than nonidentical twins because the former are more similarly affected by the same environmental conditions, but the content of those greater trait similarities is nevertheless completely malleable and determined by particular environments. The twin studies method thus can neither prove nor refute the argument for a genetic basis of political traits such as liberal and conservative preferences or voting turnout. The meaning of heritability estimates results in twin studies are discussed, as well as the definition and function of the environment in the political science twin studies. The premature attempts to associate political traits with specific genes despite countertrends in genetics are also examined. I conclude by proposing that the alternative explanation of this article may explain certain puzzles in behavioral genetics, particularly why social and political traits have higher heritability estimates than common physical and medical traits. I map the main point of disagreements with the methodology and the interpretation of its results, and delineate the main operative implications for future research.

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Rintala, Mirva, Arja Lyytikäinen, Tuija Leskinen, Markku Alen, Kirsi H. Pietiläinen, Jaakko Kaprio et Urho M. Kujala. « Leisure-time physical activity and nutrition : a twin study ». Public Health Nutrition 14, n^o 5 (4 mai 2010) : 846–52. http://dx.doi.org/10.1017/s136898001000090x.

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AbstractObjectiveTo determine the association between long-term leisure-time physical activity/inactivity and eating behaviours in twin pairs discordant for physical activity for 30 years.DesignCo-twin control design with cross-sectional data collection using questionnaire on eating habits and 5 d food diary. Differences in eating behaviours between physically active and inactive co-twins were analysed with pairwise tests.SettingFinland.SubjectsSixteen same-sex twin pairs (seven monozygotic and nine dizygotic, mean age 60 years) discordant for physical activity, selected from the Finnish Twin Cohort on the basis of physical activity discordance for 30 years, blinded to their possible differences in eating behaviours.ResultsThe eating habits questionnaire revealed that physically active co-twins more frequently reported that it is easy to eat according to need, whereas overeating and/or restrictive eating was more common among the inactive co-twins (P = 0·035). Avoiding calories was more common among the active than inactive co-twins (P = 0·034). Based on food diaries the physically active co-twins had daily energy intake on average 15·5 kJ/kg higher than their inactive co-twins (P = 0·030). The active co-twins also had a higher intake of vitamin C (P = 0·004), total water (P = 0·044), legumes and nuts (P = 0·015) and sweets (P = 0·036), as well as a lower energy-adjusted intake of meat (P = 0·013).ConclusionsThe physically active persons seem to eat more but not necessarily healthier food. However, habitual physical activity may help in eating according to need and in reaching and maintaining a healthy body composition. Therefore, it is necessary to incorporate both dietary and physical activity advice into health counselling.

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Tekinerdogan, Bedir. « On the Notion of Digital Twins : A Modeling Perspective ». Systems 11, n^o 1 (30 décembre 2022) : 15. http://dx.doi.org/10.3390/systems11010015.

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A digital twin is a digital replica of a physical entity that can be remotely controlled, which allows for sophisticated control for a variety of reasons. Digital twins are made possible using various technologies such as Internet of Things, sensor technology, artificial intelligence, data science, and machine learning. With this, it represents a new stage in smart systems engineering. Developing digital twin-based systems necessitates a holistic system engineering approach in which modeling is critical. Various studies have been published on the notion of digital twins and its applications in various domains, but a modeling perspective has not been explicitly considered. Hence, this article provides a novel insight on the notion of digital twins from a modeling perspective, describing the evolution of modeling in engineering and likewise providing a rational basis for digital twins as a next logical step in modeling. A metamodel is provided that integrates the key concepts of systems engineering, digital twins, and modeling. While elaborating on the existing evolution of modeling in engineering, it is stated that the next step of digital twins will be artificial twins.

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Pronost, Guillaume, Frédérique Mayer, Mauricio Camargo et Laurent Dupont. « Digital Twins along the product lifecycle : A systematic literature review of applications in manufacturing ». Digital Twin 3 (8 mars 2024) : 3. http://dx.doi.org/10.12688/digitaltwin.17807.2.

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Background The evolution of product expectations in the era of mass personalization implies an improvement and a better control of individualized creation and production processes throughout the product lifecycle. The application of the digital twin seems to be a favoured solution in this context, but its study during the lifecycle of a product has only been partially evoked in the literature. Methods The purpose of this research is to identify the leverages and barriers to support the digital twin diffusion in the manufacturing industry from a technological, operational, and social standpoint. To determine these elements, this paper will identify current digital twins applications in the literature under two main dimensions: the type of digital twin, and its applications along the product lifecycle. To achieve this analysis a systematic literature review was carried out. The publications selection was based on the presence in these of a case of application of a digital twin with a focus in the Manufacturing sector. Within this review, 188 scientific papers were comprehensively compiled and analyzed. Results Results showed that although the term digital twin is widely used, the deployment of digital twin technologies in manufacturing is still at an early stage as most of the reported digital twin applications were in fact prototypes focused on the real-time observability of the physical system, either for optimization or predictive maintenance. Moreover, regarding the product lifecycle, most of the applications have been focused on the production and operational phases whereas those at the design and disposal phases are still limited. Conclusions This paper presents an original approach to the study of digital twins, focusing simultaneously on the type of digital twin, the application area and the lifecycle phase. Under the basis of the obtained results, future perspectives on the use of digital twins along the lifecycle are proposed.

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Miao, Bing, Shirong Ge, Yinan Guo, Jiaxin Zhou et Ersong Jiang. « Construction of digital twin system for intelligent mining in coal mines ». Metaverse 3, n^o 2 (15 septembre 2022) : 16. http://dx.doi.org/10.54517/m.v3i2.2130.

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In order to fulfill the functions of comprehensive perception, real time interconnection, analysis and decision making, autonomous learning, dynamic prediction and cooperative control, an overall framework of Digital Twin Smart Mining Workface was established. Firstly, the digital twin smart mining face system was divided into 3 levels, and the functions and characteristics of each level were given. Secondly, based on the physical domain entities contained in the intelligent mining face, the data perception models of coal shearer, scraper conveyor, stage loader, crusher, hydraulic support, belt conveyor support, emulsion pump station and environment in the digital twin working face system were expounded in detail, and the collaborative constraint relationship among shearer, hydraulic support, coal flow transportation system, workface environment and equipment was analyzed in depth. Finally, the application scheme of the digital twin intelligent mining face system was designed. Based on the digital twin intelligent mining face system, the virtual real mapping and real time interaction between physical mine entities and digital mine twins could be realized, and the intelligent perception and cooperative control of digital twins could be performed, which provides a basis for improving the intelligent level of coal mining face.

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Miao, Bing, Shirong Ge, Yinan Guo, Jiaxin Zhou et Ersong Jiang. « Construction of digital twin system for intelligent mining in coal mines ». Metaverse 3, n^o 2 (15 septembre 2022) : 16. http://dx.doi.org/10.54517/met.v3i2.2130.

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In order to fulfill the functions of comprehensive perception, real time interconnection, analysis and decision making, autonomous learning, dynamic prediction and cooperative control, an overall framework of Digital Twin Smart Mining Workface was established. Firstly, the digital twin smart mining face system was divided into 3 levels, and the functions and characteristics of each level were given. Secondly, based on the physical domain entities contained in the intelligent mining face, the data perception models of coal shearer, scraper conveyor, stage loader, crusher, hydraulic support, belt conveyor support, emulsion pump station and environment in the digital twin working face system were expounded in detail, and the collaborative constraint relationship among shearer, hydraulic support, coal flow transportation system, workface environment and equipment was analyzed in depth. Finally, the application scheme of the digital twin intelligent mining face system was designed. Based on the digital twin intelligent mining face system, the virtual real mapping and real time interaction between physical mine entities and digital mine twins could be realized, and the intelligent perception and cooperative control of digital twins could be performed, which provides a basis for improving the intelligent level of coal mining face.

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Mack, Thomas M., Dennis Deapen et Ann S. Hamilton. « Representativeness of a roster of volunteer North American twins with chronic disease ». Twin Research 3, n^o 1 (1 février 2000) : 33–42. http://dx.doi.org/10.1375/twin.3.1.33.

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AbstractTo identify large numbers of twins affected by chronic disease as potential subjects for studies of environmental and genetic chronic disease determinants, we advertised for affected twins over the period 1980–91 in newspapers across North America. Responses were received from 17 245 twin pairs in which cases of cancer or other chronic disease had occurred. To assess the representativeness of affected twins identified by advertising, we evaluated the pattern of reporting, compared the cases identified to the number of cases estimated to be prevalent among all North American twins, compared the cases to population-based singleton case series, compared the healthy co-twins to population-based samples of healthy persons, assessed the impact on ascertainment of opinions about disease causation, compared the pattern of prospective to retrospective ascertainment of disease in the originally unaffected co-twins of cases, and compared the results of the prospective ascertainment of disease in co-twins to comparable published estimates. Youth, gender, zygosity, education, and disease concordance were found to be overall determinants of ascertainment. Disease-discordant DZ twins appeared to be modestly underascertained. While somewhat better educated, both concordant and discordant pairs were judged to be reasonably representative of affected non-Hispanic white North American twin pairs of comparable status, ie of comparable age, sex, race, and zygosity. If interpreted with caution, the concordance patterns of such twins can be used to generate genetic hypotheses, but should not be the basis of definitive heritability analyses. We conclude that advertising offers a method of identifying pairs of twins that can serve as subjects for studies designed to identify disease determinants. Twin Research (2000) 3, 33–42.

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Romani, Rossana, Mika Niemelä, Miikka Korja et Juha A. Hernesniemi. « DIZYGOTIC TWINS WITH A COLLOID CYST OF THE THIRD VENTRICLE ». Neurosurgery 63, n^o 5 (1 novembre 2008) : E1003. http://dx.doi.org/10.1227/01.neu.0000330388.91098.89.

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Abstract OBJECTIVE AND IMPORTANCE Colloid cysts of the third ventricle are rare benign tumors of endodermal origin accounting for 1% of all intracranial tumors. Interestingly, a few familial cases have been reported previously. We present the first case of dizygotic twins with a symptomatic colloid cyst of the third ventricle. CLINICAL PRESENTATION A 10-year-old boy was admitted to a local hospital in 1993 because of severe progressive headache. Computed tomographic and magnetic resonance imaging scans revealed acute obstructive hydrocephalus attributable to a third ventricular colloid cyst, which was removed after emergent ventricular drainage. Fourteen years later, a nonidentical twin brother complained of continuous headache with nausea and vomiting. A magnetic resonance imaging scan showed obstructive hydrocephalus and a third ventricle colloid cyst, which was removed by use of the transcallosal approach. INTERVENTION Both twins underwent complete removal of the cyst by the interhemispheric transcallosal approach without postoperative complications. CONCLUSION On the basis of a literature review, 2 cases of colloid cysts of the third ventricle in monozygotic twins and a few familial cases have been reported. Our case is the first in dizygotic twin brothers. These findings suggest that the prevalence of colloid cyst may be higher in twins than in the general population. We believe that the presence of this lesion in a twin necessitates magnetic resonance imaging of the other twin, and a clinical follow-up would be recommended in all other first-degree relatives.

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Da Cunha, Artur Henrique Galvao Bruno, Pedro Guerra, Renata Raizza Monterazzo Cysneiros et Inaê Carolline Silveira Da Silva. « Concordance factors in craniosynostosis twins : a meta-analysis and case report ». Archives of Pediatric Neurosurgery 6, n^o 2 (1 mai 2024) : e2452024. http://dx.doi.org/10.46900/apn.v6i2.245.

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Introductions: Craniosynostosis is a condition where the cranial sutures close prematurely. It is influenced by both genetics and environment. This paper focuses on craniosynostosis in twins, which is an understudied area. It presents a case report of male identical twins and conducts a meta-analysis based on 34 articles to understand the factors affecting concordance in twins who have craniosynostosis. The study considers factors such as zygosity, gender, genetic syndromes, and the type of synostosis. Material and methods: A meta-analysis was conducted on 105 twin pairs (210 patients) identified from studies carried out between 1963 to 2023. The eligible studies, based on PICO criteria, included case reports and case series focusing on twins with craniosynostosis. A systematic literature search was conducted on PUBMED and Mendeley platforms to gather data on gestational age, zygosity, genetic syndromes, affected sutures, and concordance. Results: The report is about two identical twin brothers who had sagittal and metopic suture synostosis. They were treated successfully with cranial remodeling surgery. In a meta-analysis of 105 twin pairs (210 patients) , a total of 25.9% showed concordance. The study found a significant difference in concordance between monozygotic (45.3%) and dizygotic (7.3%) twins. The analysis also revealed that twins with scaphocephaly had a higher degree of concordance than those with trigonocephaly (46.7% vs. 18.9%, respectively). The study did not find any significant correlation between gender, the presence of genetic syndromes, and concordance. Conclusion: This investigation highlights the complex interplay of genetic and environmental factors in craniosynostosis in twins. The higher concordance in monozygotic twins emphasizes the genetic basis. These findings validate existing literature and provide new insights.

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Locke, John L., et Patricia L. Mather. « Genetic factors in the ontogeny of spoken language : evidence from monozygotic and dizygotic twins ». Journal of Child Language 16, n^o 3 (octobre 1989) : 553–59. http://dx.doi.org/10.1017/s0305000900010710.

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ABSTRACTRecent controversy about the innateness of language has awakened interest in the genetic basis of linguistic development. In this study, we analysed more extensively data from Mather & Black (1984).in order to test the hypothesis that the speech articulation of monozygotic (MZ) twins would be qualitatively more similar than that of age- and sex-matched dizygotic (DZ) twins. Analyses revealed that 4–year-old MZ twin pairs were significantly more likely to misproduce the same sounds on an articulation test than were DZ twin pairs, and that DZ twins were no more likely to share errors than were children who were both genetically and environmentally unrelated. There was no evidence that MZ twins made more similar errors than DZ twins, and indeed it was difficult to make this determination since only broad categories of error (substitution, distortion, omission) were available for analysis. The greater amount of genetic material shared by MZ twins, and the presumably more similar morphology of their speech mechanisms, may have caused certain sound patterns to be of more nearly equal difficulty for both members of a MZ pair. However, these findings need to be confirmed with phonetically more detailed analyses.

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Resman, Matevz, Jernej Protner, Marko Simic et Niko Herakovic. « A Five-Step Approach to Planning Data-Driven Digital Twins for Discrete Manufacturing Systems ». Applied Sciences 11, n^o 8 (18 avril 2021) : 3639. http://dx.doi.org/10.3390/app11083639.

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A digital twin of a manufacturing system is a digital copy of the physical manufacturing system that consists of various digital models at multiple scales and levels. Digital twins that communicate with their physical counterparts throughout their lifecycle are the basis for data-driven factories. The problem with developing digital models that form the digital twin is that they operate with large amounts of heterogeneous data. Since the models represent simplifications of the physical world, managing the heterogeneous data and linking the data with the digital twin represent a challenge. The paper proposes a five-step approach to planning data-driven digital twins of manufacturing systems and their processes. The approach guides the user from breaking down the system and the underlying building blocks of the processes into four groups. The development of a digital model includes predefined necessary parameters that allow a digital model connecting with a real manufacturing system. The connection enables the control of the real manufacturing system and allows the creation of the digital twin. Presentation and visualization of a system functioning based on the digital twin for different participants is presented in the last step. The suitability of the approach for the industrial environment is illustrated using the case study of planning the digital twin for material logistics of the manufacturing system.

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Bahig, Houda, Tina Petrogiannis-Haliotis, Kevin L. Pehr et David Roberge. « Primary Cutaneous B-Cell Lymphoma in Young Monozygotic Twins ». Journal of Cutaneous Medicine and Surgery 20, n^o 6 (7 juillet 2016) : 582–85. http://dx.doi.org/10.1177/1203475416658000.

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Although familial aggregation of lymphoproliferative disorders has been described, heredity has not been implicated in the etiology of primary cutaneous B-cell lymphomas (PCBCL). We report herein the first case of 2 young monozygotic twins with PCBCL. The first twin was an 18-year-old woman when she presented with multiple skin nodules on the thorax and head. Histology showed an atypical small B-cell proliferation, consistent with primary cutaneous marginal zone lymphoma (PCMZL). Molecular genetics studies demonstrated B-cell clonality. Seven years later, the second twin developed her first lesion that was histologically similar to that of her twin. She subsequently developed other clinically similar lesions. Histology was consistent with PCMZL and showed B-cell clonality. Occurrence of PCBCL in these monozygotic twins raises the possibility of a genetic risk factor. Further study of such rare cases may offer valuable insights into the molecular basis of the etiology and pathogenesis of this unusual disorder.

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Moravek, Alexander, Jennifer G. Murphy, Amy Hrdina, John C. Lin, Christopher Pennell, Alessandro Franchin, Ann M. Middlebrook et al. « Wintertime spatial distribution of ammonia and its emission sources in the Great Salt Lake region ». Atmospheric Chemistry and Physics 19, n^o 24 (20 décembre 2019) : 15691–709. http://dx.doi.org/10.5194/acp-19-15691-2019.

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Abstract. Ammonium-containing aerosols are a major component of wintertime air pollution in many densely populated regions around the world. Especially in mountain basins, the formation of persistent cold-air pools (PCAPs) can enhance particulate matter with diameters less than 2.5 µm (PM2.5) to levels above air quality standards. Under these conditions, PM2.5 in the Great Salt Lake region of northern Utah has been shown to be primarily composed of ammonium nitrate; however, its formation processes and sources of its precursors are not fully understood. Hence, it is key to understanding the emission sources of its gas phase precursor, ammonia (NH3). To investigate the formation of ammonium nitrate, a suite of trace gases and aerosol composition were sampled from the NOAA Twin Otter aircraft during the Utah Winter Fine Particulate Study (UWFPS) in January and February 2017. NH3 was measured using a quantum cascade tunable infrared laser differential absorption spectrometer (QC-TILDAS), while aerosol composition, including particulate ammonium (pNH4), was measured with an aerosol mass spectrometer (AMS). The origin of the sampled air masses was investigated using the Stochastic Time-Inverted Lagrangian Transport (STILT) model and combined with an NH3 emission inventory to obtain model-predicted NHx (=NH3+pNH4) enhancements. Enhancements represent the increase in NH3 mixing ratios within the last 24 h due to emissions within the model footprint. Comparison of these NHx enhancements with measured NHx from the Twin Otter shows that modelled values are a factor of 1.6 to 4.4 lower for the three major valleys in the region. Among these, the underestimation is largest for Cache Valley, an area with intensive agricultural activities. We find that one explanation for the underestimation of wintertime emissions may be the seasonality factors applied to NH3 emissions from livestock. An investigation of inter-valley exchange revealed that transport of NH3 between major valleys was limited and PM2.5 in Salt Lake Valley (the most densely populated area in Utah) was not significantly impacted by NH3 from the agricultural areas in Cache Valley. We found that in Salt Lake Valley around two thirds of NHx originated within the valley, while about 30 % originated from mobile sources and 60 % from area source emissions in the region. For Cache Valley, a large fraction of NOx potentially leading to PM2.5 formation may not be locally emitted but mixed in from other counties.

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CHUA, LEON O., VALERY I. SBITNEV et SOOK YOON. « A NONLINEAR DYNAMICS PERSPECTIVE OF WOLFRAM'S NEW KIND OF SCIENCE PART VI : FROM TIME-REVERSIBLE ATTRACTORS TO THE ARROW OF TIME ». International Journal of Bifurcation and Chaos 16, n^o 05 (mai 2006) : 1097–373. http://dx.doi.org/10.1142/s0218127406015544.

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This paper proves, via an analytical approach, that 170 (out of 256) Boolean CA rules in a one-dimensional cellular automata (CA) are time-reversible in a generalized sense. The dynamics on each attractor of a time-reversible rule N is exactly mirrored, in both space and time, by its bilateral twin ruleN†. In particular, all 69 period-1 rules, 17 (out of 25) period-2 rules, and 84 (out of 112) Bernoulli rules are time-reversible. The remaining 86 CA rules are time-irreversible in the sense that N and N† mirror their dynamics only in space, but not in time. In this case, each attractor of N defines a unique arrow of time. A simple "time-reversal test" is given for testing whether an attractor of a CA rule is time-reversible or time-irreversible. For a time-reversible attractor of a CA rule N the past can be uniquely recovered from the future of N†, and vice versa. This remarkable property provides 170 concrete examples of CA time machines where time travel can be routinely achieved by merely hopping from one attractor to its bilateral twin attractor, and vice versa. Moreover, the time-reversal property of some local rules can be programmed to mimic the matter–antimatter "annihilation" or "pair-production" phenomenon from high-energy physics, as well as to mimic the "contraction" or "expansion" scenarios associated with the Big Bang from cosmology. Unlike the conventional laws of physics, which are based on a unique universe, most CA rules have multiple universes (i.e. attractors), each blessed with its own laws. Moreover, some CA rules are endowed with both time-reversible attractors and time-irreversible attractors. Using an analytical approach, the time-τ return map of each Bernoulli στ-shift attractor of all 112 Bernoulli rules are shown to obey an ultra-compact formula in closed form, namely,. [Formula: see text] or its inverse map. These maps completely characterize the time-asymptotic (steady state) behavior of the nonlinear dynamics on the attractors. In-depth analysis of all but 18 global equivalence classes of CA rules have been derived, along with their basins of attraction, which characterize their transient regimes. Above all, this paper provides a rigorous nonlinear dynamics foundation for a paradigm shift from an empirical-based approach à la Wolfram to an attractor-based analytical theory of cellular automata.

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Balla, Michal, Oto Haffner, Erik Kučera et Ján Cigánek. « Educational Case Studies : Creating a Digital Twin of the Production Line in TIA Portal, Unity, and Game4Automation Framework ». Sensors 23, n^o 10 (22 mai 2023) : 4977. http://dx.doi.org/10.3390/s23104977.

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In today’s industry, the fourth industrial revolution is underway, characterized by the integration of advanced technologies such as artificial intelligence, the Internet of Things, and big data. One of the key pillars of this revolution is the technology of digital twin, which is rapidly gaining importance in various industries. However, the concept of digital twins is often misunderstood or misused as a buzzword, leading to confusion in its definition and applications. This observation inspired the authors of this paper to create their own demonstration applications that allow the control of both the real and virtual systems through automatic two-way communication and mutual influence in context of digital twins. The paper aims to demonstrate the use of digital twin technology aimed at discrete manufacturing events in two case studies. In order to create the digital twins for these case studies, the authors used technologies as Unity, Game4Automation, Siemens TIA portal, and Fishertechnik models. The first case study involves the creation of a digital twin for a production line model, while the second case study involves the virtual extension of a warehouse stacker using a digital twin. These case studies will form the basis for the creation of pilot courses for Industry 4.0 education and can be further modified for the development of Industry 4.0 educational materials and technical practice. In conclusion, selected technologies are affordable, which makes the presented methodologies and educational studies accessible to a wide range of researchers and solution developers tackling the issue of digital twins, with a focus on discrete manufacturing events.

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Kovalyov, S. P. « Development of a Platform for Distributed Energy Resources Management on the Basis of a Digital Twin ». Mekhatronika, Avtomatizatsiya, Upravlenie 24, n^o 3 (28 mars 2023) : 131–41. http://dx.doi.org/10.17587/mau.24.131-141.

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The paper discusses the development of a platform for distributed energy resources management based on digital twins. The platform use cases include demand response, electric vehicle charging, peer-to-peer energy trading, storage scheduling, virtual power plant, and so on. Thanks to the digital twin, the platform can perform the use cases controlling either real operation-stage equipment or virtual design-stage simulation models. The platform offers mass distributed energy resources owners and operators to improve the power supply quality (including stability), reduce costs (including transaction overhead), and gain emerging market opportunities (including participation in various aggregators' programs). Software and equipment vendors are interested in the platform's capability to quickly assemble distributed energy management systems almost without programming. The digital twin and the platform are designed with the viewpoint-based approach established by the international systems engineering standard ISO/IEC/IEEE 42010. The typical power system digital twin architecture is described. The major kinds of mathematical models as part of digital twins are presented: physical models based on numerical solutions of differential equations and optimization problems, machine learning models, knowledge-based models. The interoperability of such heterogeneous models is ensured on the basis of the ontological model of distributed energy. The platform architecture is represented from three key viewpoints: functional, information, and software. To formalize and ultimately automate the integration of heterogeneous models, we propose novel mathematical methods of model-based system engineering based on category theory, including universal constructions and the multicomma. The multicomma category is shown to be constructed using standard product, exponent, and pushout constructions, which makes it possible to establish a number of its practically significant properties.

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Tsohla, Svetlana Yuryevna, et Natalia Alexandrovna Simchenko. « Accumulation of intellectual and technological potential of the industrial company on the basis of digital twins ». KANT 40, n^o 3 (mars 2021) : 110–14. http://dx.doi.org/10.24923/2222-243x.2021-40.21.

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The purpose of the study is to reveal the prerequisites for the accumulation of intellectual and technological potential of an industrial company based on digital twins. The article discusses the application of digital twin technology in industry. The scientific novelty lies in the substantiation of the definition of intellectual potential in terms of creative and professional components in the context of digital provision of jobs in the course of the use of digital twin technology, which will allow accumulating the positive experience and technological potential of the company. As a result, the components of intellectual and technological potential in ensuring productivity growth and competitive advantages of industrial companies have been identified. The level of innovative development and the dynamics of developed advanced production technologies in Russia have been investigated.

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Almarzouki, Hashem S., Alaa A. Tayyib, Hassan A. Khayat, Raed E. Alsulami, Saeed M. Alzahrani, Abdulaziz S. Alkahtani et Loai S. Alghifees. « Peters Anomaly in Twins : A Case Report of a Rare Incident with Novel Comorbidities ». Case Reports in Ophthalmology 7, n^o 3 (10 octobre 2016) : 464–70. http://dx.doi.org/10.1159/000450571.

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Introduction: Peters anomaly is a rare developmental malformation involving the anterior segment of the eye, which culminates in amblyopia or congenital blindness. Multiple ocular and/or systemic malformations have been observed with this anomaly, and novel comorbidities continue to be reported. Case Presentation: The probands were monozygotic twin boys (twin I and twin II) born to consanguineous parents at 36 weeks of gestation. Coarse facial features and deep-seated eyes were noted at birth. At 6 months, ophthalmic examination revealed that both twins were unable to blink in response to light, or to fixate and follow a moving object. Both twins had prominent horizontal nystagmus. Slit-lamp examination demonstrated varying degrees of central leukoma (corneal opacity) associated with iridocorneal adhesion, which is characteristic of type I Peters anomaly. No cataractous changes were observed. Normal intraocular pressure and disorganized retina were observed. Pupillary abnormalities included bilaterally underdeveloped pupils and bilateral absence of pupils was noted. Ocular MRI showed bilateral microphthalmia and optic nerve hypoplasia, with a small optic chiasm in both twins. At this age, the diagnosis of Peters anomaly was made. At 16 months of age, both twins developed deep venous thrombosis and purpuric skin lesions. Investigations revealed a hereditary thrombophilia secondary to a homozygous mutation causing protein C deficiency, which is a rare thrombotic condition. Ocular ultrasonography revealed bilateral vitreous hemorrhaging linked to altered coagulation. One twin developed bilateral inguinal hernia and cryptorchidism. Conclusion: The novel concordance of Peters anomaly in these monozygotic twins sharing a mutation in PROC gene provides further evidence that this anomaly has a genetic basis. Hypoplasia of the optic nerves and optic chiasm, along with severe protein C deficiency and bilateral absence of the pupils, are associated comorbidities that have not previously been reported with this anomaly.

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Taneva, Emiliya, Carla Evans et Grace Viana. « 3D Evaluation of Palatal Rugae in Identical Twins ». Case Reports in Dentistry 2017 (2017) : 1–6. http://dx.doi.org/10.1155/2017/2648312.

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The study of identical twins can point out potential limitations in biometrics and forensic odontology. This case report presents three-dimensional (3D) palatal rugae analysis in monozygotic twins utilizing digital models obtained directly by scanning the maxillary dental arch with the iTero® intraoral digital scanner. The results show that the rugae patterns contain related but not identical features between the pair of identical twins. Dental study models taken on a regular basis for diagnosis and treatment planning in dentistry include the palatal rugae, which could be valuable to forensics in identical twin identification cases.

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Han, Xue, Zihuai Lin, Cameron Clark, Branka Vucetic et Sabrina Lomax. « AI Based Digital Twin Model for Cattle Caring ». Sensors 22, n^o 19 (20 septembre 2022) : 7118. http://dx.doi.org/10.3390/s22197118.

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In this paper, we develop innovative digital twins of cattle status that are powered by artificial intelligence (AI). The work is built on a farm IoT system that remotely monitors and tracks the state of cattle. A digital twin model of cattle based on Deep Learning (DL) is generated using the sensor data acquired from the farm IoT system. The physiological cycle of cattle can be monitored in real time, and the state of the next physiological cycle of cattle can be anticipated using this model. The basis of this work is the vast amount of data that is required to validate the legitimacy of the digital twins model. In terms of behavioural state, this digital twin model has high accuracy, and the loss error of training reach about 0.580 and the loss error of predicting the next behaviour state of cattle is about 5.197 after optimization. The digital twins model developed in this work can be used to forecast the cattle’s future time budget.

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Ojstersek, R., A. Javernik et B. Buchmeister. « Optimizing smart manufacturing systems using digital twin ». Advances in Production Engineering & ; Management 18, n^o 4 (28 décembre 2023) : 475–85. http://dx.doi.org/10.14743/apem2023.4.486.

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Presented paper investigates the application of digital twins for the optimisation of intelligent manufacturing systems and focuses on the comparison between simulation modelling results and real-world production conditions. A digital twin was created in the Simio software environment using a data-driven simulation model derived from a real-world production system. Running the digital twin in real time, which was displayed graphically, facilitated the analysis of key parameters, including the number of finished products, average flow time, workstation utilization and product quality. The discrepancies were attributed to the use of random distributions of input data in the dynamic digital twin, as opposed to the long-term measurements and averages in the real-world system. Despite the limitations in the case study, the results underline the financial justification and predictive capabilities of digital twins for optimising production systems. Real-time operation enables continuous evaluation and tracking of parameters and offers high benefits for intelligent production systems. The study emphasises the importance of accurate selection of input data and warns that even small deviations can lead to inaccurate results. Finally, the paper high-lights the role of digital twins in optimising production systems and argues for careful consideration of input data. It highlights the importance of analysing real-world production systems and creating efficient simulation models as a basis for digital twin solutions. The results encourage extending the research to different types of production, from job shop to mass production, in order to obtain a comprehensive optimisation perspective.

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