Journal articles: 'Mathematical precursors'

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Cirino, Paul T. "The interrelationships of mathematical precursors in kindergarten." Journal of Experimental Child Psychology 108, no. 4 (April 2011): 713–33. http://dx.doi.org/10.1016/j.jecp.2010.11.004.

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Nogues, Camila Peres, and Beatriz Vargas Dorneles. "Systematic review on the precursors of initial mathematical performance." International Journal of Educational Research Open 2-2 (2021): 100035. http://dx.doi.org/10.1016/j.ijedro.2021.100035.

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Guzev, Mikhail, and Vladimir Makarov. "Investigation of Deformation of Rock Samples." Key Engineering Materials 744 (July 2017): 61–65. http://dx.doi.org/10.4028/www.scientific.net/kem.744.61.

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Deformation of rock samples compressed up to failure has been studied in laboratory. A system of trustworthy deformational precursors of the failure stage has been developed. The system includes long-term, middle-term and short-term precursors, which correspond to the threshold of dilatancy, change of the specific volume deformation, and jump of the specific volume deformation increments, respectively. Proposed methods of the complex research include deformation and mathematical methods. The mathematical model of deformation in samples of rocks at uniaxial compression is founded on hypothesis of self-equilibrium stresses. The model had been successfully used for description of oscillating deformation. Good coincidence between the experimental and theoretical results has been observed.

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Sajid, Muhammad, Apu Chowdhury, Ghulam Bary, Yin Guoliang, Riaz Ahmad, Ilyas Khan, Waqar Ahmed, Muhammad Farooq Saleem Khan, Aisha M. Alqahtani, and Md Nur Alam. "Conversion of Fructose to 5-Hydroxymethyl Furfural: Mathematical Solution with Experimental Validation." Journal of Mathematics 2022 (April 29, 2022): 1–8. http://dx.doi.org/10.1155/2022/6989612.

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Conversion of fructose to furan aldehydes is a rapidly developing concept considering the emergent scenario of the replacement of fossil-derived components to biomass-derived green precursors. 5-hydroxymethyl furfural (HMF) and levulinic acid (LA) are the two most important bio-precursors with expanded downstream utilization in modern industries. Their production from biomass-derived sugars is a complex reaction due to competitive side reactions with a variety of byproducts. Therefore, their simulated optimization is an important tool that can help for process optimization in an economical way. In this article, we have developed a mathematical solution for fructose conversion, HMF production, and levulinic acid (LA) formation in a reactive environment. The accuracy of the developed model is further verified through experiments and found satisfactory with high accuracy. Therefore, the developed model can be used to simulate the reaction environment and product optimization under a given set of conditions.

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Zolotov, O. V., A. A. Namgaladze, I. E. Zakharenkova, O. V. Martynenko, and I. I. Shagimuratov. "Physical interpretation and mathematical simulation of ionospheric precursors of earthquakes at midlatitudes." Geomagnetism and Aeronomy 52, no. 3 (May 2012): 390–97. http://dx.doi.org/10.1134/s0016793212030152.

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KHAN, K. M., W. AHMAD, and K. IQBAL. "A NONTHERMAL MODEL FOR CATALYTIC SURFACE REACTION OF THE TYPE A2+B2→2AB: A MONTE CARLO SIMULATION STUDY." International Journal of Modern Physics C 14, no. 10 (December 2003): 1413–26. http://dx.doi.org/10.1142/s0129183103005492.

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The kinetics of irreversible dimer–dimer reaction of the type A2+B2→2AB has already been studied through Monte Carlo simulation via a model based on Langmuir–Hinshelwood (thermal) mechanism. The results of this study are well known. There is single transition point (yC) at yB=0.5 (where yB is partial pressure of B2 dimer in gas phase), which separates the two poisoned states from each other. Here, we have studied this reaction on the basis of a nonthermal model, which involves the precursor motion of B2 molecule. The most interesting feature of this model is that it yields a steady reactive window. The phase diagram is similar to the ZGB model. The reactive window is separated by continuous and discontinuous irreversible phase transitions. The width of the reactive window depends upon the mobility of the precursors. The dependence of production rate on partial pressure of B2 is shown by simple mathematical equations in our model. Some interesting results are observed when reaction between precursors and chemisorbed B atoms is considered.

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Bazan, Carlos. "Effect of the University’s Environment and Support System on Subjective Social Norms as Precursor of the Entrepreneurial Intention of Students." SAGE Open 12, no. 4 (October 2022): 215824402211291. http://dx.doi.org/10.1177/21582440221129105.

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In this study, we aim to understand the influence of the university’s environment and support system (ESS) on subjective social norms (SSN) as one of the precursors of the entrepreneurial intention (EI) of university students. For this, we applied a customized mathematical model of EI based on the theory of planned behavior to probe whether the university’s ESS can affect SSN and analyze the paths that this influence may follow to form the EI of students. In other words, this study argues that the university plays a critical dual role in shaping the EI of students. First, it can provide support mechanisms to help students translate their ideas into viable business models that may further translate into successful ventures. Second, it can help students gain the support of their families and friends who influence their SSN, thus affecting their EI through the mediating effects of the other two precursors of intention. We collected the data from students in a public university in Atlantic Canada via a structured non-disguised questionnaire to test the hypotheses formulated in this study. We analyzed them through partial least square-structural equation modeling of a second-order mathematical model of EI. Analysis of the data indicates that the mathematical model is appropriate for evaluating the relations among the five constructs of the mathematical model of EI. Results of this study support the hypothesis that the university’s ESS may influence students’ perceptions of the opinions of important reference people regarding their prospects of becoming entrepreneurs. Furthermore, we determined that the university’s ESS influences the EI of students mediated by the more proximal precursors of intention. The effect of the university’s ESS is such that it may positively impact the EI of students, but its importance in the mathematical model of EI is still low. These findings can help universities assess their initiatives to promote innovation and entrepreneurship on campus.

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Torresi, Sandra. "Interaction between domain-specific and domain-general abilities in math´s competence." Journal of Applied Cognitive Neuroscience 1, no. 1 (December 7, 2020): 43–51. http://dx.doi.org/10.17981/jacn.1.1.2020.08.

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This article is an approach to some viewpoints about interactions between domain-specific and general cognitive tools involved in the development of mathematical competence. Many studies report positive correlations between the acuity of the numerical approximation system and formal mathematical performance, while another important group of investigations have found no evidence of a direct connection between non-symbolic and symbolic numerical representations. The challenge for future research will be to focus on correlations and possible causalities between non-symbolic and symbolic arithmetic skills and general domain cognitive skills in order to identify stable precursors of mathematical competence.

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Polonsky, Michal, Jacob Rimer, Amos Kern-Perets, Irina Zaretsky, Stav Miller, Chamutal Bornstein, Eyal David, et al. "Induction of CD4 T cell memory by local cellular collectivity." Science 360, no. 6394 (June 14, 2018): eaaj1853. http://dx.doi.org/10.1126/science.aaj1853.

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Cell differentiation is directed by signals driving progenitors into specialized cell types. This process can involve collective decision-making, when differentiating cells determine their lineage choice by interacting with each other. We used live-cell imaging in microwell arrays to study collective processes affecting differentiation of naïve CD4+ T cells into memory precursors. We found that differentiation of precursor memory T cells sharply increases above a threshold number of locally interacting cells. These homotypic interactions involve the cytokines interleukin-2 (IL-2) and IL-6, which affect memory differentiation orthogonal to their effect on proliferation and survival. Mathematical modeling suggests that the differentiation rate is continuously modulated by the instantaneous number of locally interacting cells. This cellular collectivity can prioritize allocation of immune memory to stronger responses.

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Namgaladze, A. A., M. V. Klimenko, V. V. Klimenko, and I. E. Zakharenkova. "Physical mechanism and mathematical modeling of earthquake ionospheric precursors registered in total electron content." Geomagnetism and Aeronomy 49, no. 2 (April 2009): 252–62. http://dx.doi.org/10.1134/s0016793209020169.

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Cederlöf, M., P. Östberg, E. Pettersson, H. Anckarsäter, C. Gumpert, S. Lundström, and P. Lichtenstein. "Language and mathematical problems as precursors of psychotic-like experiences and juvenile mania symptoms." Psychological Medicine 44, no. 6 (August 13, 2013): 1293–302. http://dx.doi.org/10.1017/s0033291713002018.

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BackgroundPsychotic-like experiences (PLEs) and juvenile mania in adolescence index risk for severe psychopathology in adulthood. The importance of childhood problems with communication, reading, speech and mathematics for the development of PLEs and juvenile mania is not well understood.MethodThrough the Child and Adolescent Twin Study in Sweden, we identified 5812 children. The parents were interviewed about their children's development at age 9 or 12 years. At age 15 or 18 years, children and parents completed questionnaires targeting current PLEs and juvenile mania symptoms. Logistic regressions were used to assess associations between problems with communication, reading, speech and mathematics and PLEs/juvenile mania symptoms. To evaluate the relative importance of genes and environment in these associations, we used bivariate twin analyses based on structural equation models.ResultsChildren with parent-endorsed childhood problems with communication, reading and mathematics had an increased risk of developing auditory hallucinations and parental-reported juvenile mania symptoms in adolescence. The most consistent finding was that children with childhood problems with communication, reading and mathematics had an increased risk of developing auditory hallucinations [for example, the risk for self-reported auditory hallucinations at age 15 was increased by 96% for children with communication problems: OR (odds ratio) 1.96, 95% confidence interval (CI) 1.33–2.88]. The twin analyses showed that genetic effects accounted for the increased risk of PLEs and juvenile mania symptoms among children with communication problems.ConclusionsChildhood problems with communication, reading and mathematics predict PLEs and juvenile mania symptoms in adolescence. Similar to the case for schizophrenia and bipolar disorder, PLEs and juvenile mania may share genetic aetiological factors.

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Aunio, Pirjo, Riikka Mononen, Anu Laine, Geerdina Van der Aalsvoort, Carla Compagnie, Annemie Desoete, Evelyn Kroesbergen, et al. "Mathematical learning difficulties – snapshots of current European research." Lumat: International Journal of Math, Science and Technology Education 3, no. 5 (September 30, 2015): 647–74. http://dx.doi.org/10.31129/lumat.v3i5.1011.

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In November 2014 we had a wonderful possibility to organize a seminar International Seminar on Mathematical Learning Difficulties with our international colleagues in the field of mathematical learning difficulties. One of the main aims was to provide open lectures for the staff members and students in University of Helsinki. The meeting was supported by the Teachers’ Academy in University of Helsinki. We have collected extensive summaries of the presentations to form this special issue. The summaries are found in both English and Finnish. To sum up the main ideas from the presentations. Firstly, although mathematical learning difficulties are common, we do need more research to be able to understand the possible cognitive precursors or environmental issues affecting learning and causing problems. Secondly, we need more studies about intervention programmes designed to support the mathematical skills development in children having problems in learning mathematics. Thirdly, we also need more studies validating the positive findings in individual studies, using the same assessment and intervention tools.

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Ávila, Raymond Rosa. "Technology for Location, Analysis and Interpretation of Magnetic Alterations as Precursors of Seismic Phenomena Update." Civil Engineering Beyond Limits 2, no. 4 (September 21, 2021): 17–21. http://dx.doi.org/10.36937/cebel.2021.004.004.

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To date, several studies have shown that the Earth's magnetic field suffers alterations at the local geographical location before an earthquake occur. Its study demonstrates that the Earth’s magnetic alterations at specific local geographical zone, is a local seismic precursor alerting a proximity of an earthquake with a margin of error of approximately 10%. The electromagnetic noise from background is very confusing, but that reason was necessary to identify these electromagnetic signal precursors by filtering a large amount of noise. To isolate the electromagnetic noise, was implemented a Magnetic North deflection detection in Smart Phones Magnetometers. Using it technology, was developed a mathematical algorithm that work in combination with the Smart Phones magnetometers. This research was based using in reference the study carried out by the Department of Physics of the Faculty of Physical Sciences and Mathematics (FCFM) of the University of Chile directed by Cordado, 2018[1], in the paper called “Latitudinal variation rate of geomagnetic cutoff rigidity in the active Chilean convergent margin”.

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HUBENY, VERONIKA E. "PRECURSORS SEE INSIDE BLACK HOLES." International Journal of Modern Physics D 12, no. 09 (October 2003): 1693–98. http://dx.doi.org/10.1142/s0218271803003992.

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We consider, within a string theoretic context, the accessibility of events inside a black hole horizon. We present a gedankenexperiment which uses the nonlocal nature of precursors in the AdS/CFT correspondence, as well as the global nature of event horizons, to argue that the dual field theory does contain information about physics inside black holes. This alleviates the causal obstacles to accessing behind-the-horizon physics, thereby rendering more tractable certain long-standing questions of quantum gravity, such as the information paradox and possibly even singularity resolution.

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Toll, Sylke W. M., Sanne H. G. Van der Ven, Evelyn H. Kroesbergen, and Johannes E. H. Van Luit. "Executive Functions as Predictors of Math Learning Disabilities." Journal of Learning Disabilities 44, no. 6 (December 22, 2010): 521–32. http://dx.doi.org/10.1177/0022219410387302.

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In the past years, an increasing number of studies have investigated executive functions as predictors of individual differences in mathematical abilities. The present longitudinal study was designed to investigate whether the executive functions shifting, inhibition, and working memory differ between low achieving and typically achieving children and whether these executive functions can be seen as precursors to math learning disabilities in children. Furthermore, the predictive value of working memory ability compared to preparatory mathematical abilities was examined. Two classifications were made based on (persistent) mathematical ability in first and second grade. Repeated measures analyses and discriminant analyses were used to investigate which functions predicted group membership best. Group differences in performance were found on one inhibition and three working memory tasks. The working memory tasks predicted math learning disabilities, even over and above the predictive value of preparatory mathematical abilities.

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Makarov, Vladimir. "Method of Reduction of Geodynamical Phenomena Catastrophical Effects on the Base of Multichannel Methods of the Precursors Finding." E3S Web of Conferences 129 (2019): 01024. http://dx.doi.org/10.1051/e3sconf/201912901024.

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Decrease in risk of catastrophic consequences of the geodynamic phenomena of phylum of rock bursts or earthquakes demands the development of prognosis base of these events. Research of laws of formation and development of mesocracking structures on rocks samples is the most effective path of dilating of representations about mechanisms of the geodynamic phenomena and working out of methods of reduction of risks of their catastrophic exhibitings. Mathematical modelling of mesocracking structures of various hierarchical level of geomedium demands, in turn, development of theoretical base of modelling, to transferring to calibrating models of mesomechanics. In this case, of the geomedium is represented as a thermodynamically open hierarchical-block system. Addition of such models with system of strength criteria reflecting mechanisms of shear-tension of destruction at strong compression, should become the forecasting base of preparation of the geodynamic phenomena. The methods of detection of the precursors including as precursors developed on the basis of these representations, falling into source, and to near the source areas, have multichannel character. It is defined by conditions, on the one hand, independence of such systems of precursors, and, with another one – a simultaneity and synchrony of the submitted signals serving by precursors.

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Hyrien, Ollivier, Jörg Dietrich, and Mark Noble. "Mathematical and Experimental Approaches to Identify and Predict the Effects of Chemotherapy on Neuroglial Precursors." Cancer Research 70, no. 24 (November 5, 2010): 10051–59. http://dx.doi.org/10.1158/0008-5472.can-10-1400.

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Träff, Ulf, Linda Olsson, Kenny Skagerlund, and Rickard Östergren. "Kindergarten domain-specific and domain-general cognitive precursors of hierarchical mathematical development: A longitudinal study." Journal of Educational Psychology 112, no. 1 (January 2020): 93–109. http://dx.doi.org/10.1037/edu0000369.

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Moreno-Zambrano, Mauricio, Sergio Grimbs, Matthias S. Ullrich, and Marc-Thorsten Hütt. "A mathematical model of cocoa bean fermentation." Royal Society Open Science 5, no. 10 (October 2018): 180964. http://dx.doi.org/10.1098/rsos.180964.

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Cocoa bean fermentation relies on the sequential activation of several microbial populations, triggering a temporal pattern of biochemical transformations. Understanding this complex process is of tremendous importance as it is known to form the precursors of the resulting chocolate’s flavour and taste. At the same time, cocoa bean fermentation is one of the least controlled processes in the food industry. Here, a quantitative model of cocoa bean fermentation is constructed based on available microbiological and biochemical knowledge. The model is formulated as a system of coupled ordinary differential equations with two distinct types of state variables: (i) metabolite concentrations of glucose, fructose, ethanol, lactic acid and acetic acid and (ii) population sizes of yeast, lactic acid bacteria and acetic acid bacteria. We demonstrate that the model can quantitatively describe existing fermentation time series and that the estimated parameters, obtained by a Bayesian framework, can be used to extract and interpret differences in environmental conditions. The proposed model is a valuable tool towards a mechanistic understanding of this complex biochemical process, and can serve as a starting point for hypothesis testing of new systemic adjustments. In addition to providing the first quantitative mathematical model of cocoa bean fermentation, the purpose of our investigation is to show how differences in estimated parameter values for two experiments allow us to deduce differences in experimental conditions.

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Kelleher, J. K., A. T. Kharroubi, T. A. Aldaghlas, I. B. Shambat, K. A. Kennedy, A. L. Holleran, and T. M. Masterson. "Isotopomer spectral analysis of cholesterol synthesis: applications in human hepatoma cells." American Journal of Physiology-Endocrinology and Metabolism 266, no. 3 (March 1, 1994): E384—E395. http://dx.doi.org/10.1152/ajpendo.1994.266.3.e384.

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Cholesterol synthesis from 13C-labeled precursors produces a discrete spectrum of mass isotopomers detectable using gas chromatography-mass spectrometry. The isotopomer spectral analysis (ISA) method matches the observed spectrum of cholesterol isotopomers with a mathematical model to obtain the best fit of model spectrum to data spectrum. The model was based on multinomial probability expressions that simulate cholesterol synthesis as a condensation of mevalonate fragments. As many as four unknown parameters, representing fluxes between compartments, were included in the model. Models were developed to assess cholesterol synthesis from 13C-enriched precursors including mevalonate, acetate, acetoacetate or octanoate. Models were tested in the human hepatoma cell line, Hep G2, which readily incorporated the 13C substrates into cholesterol. The ISA approach was used to estimate the fractional amount of the cholesterol precursors derived from the 13C substrate and the fraction of total cellular cholesterol synthesized in the presence of the 13C substrate. The study demonstrated the feasibility of the ISA approach for a condensation biosynthesis that is not a simple polymerization and for models with more than two unknown parameters.

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Chashechkin, Yuli D. "Singular perturbed components of flows – linear precursors of shock waves." Mathematical Modelling of Natural Phenomena 13, no. 2 (2018): 17. http://dx.doi.org/10.1051/mmnp/2018020.

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A comparative analysis of the infinitesimal symmetries of various well-known systems of governing equations used for mathematical descriptions of flows and waves in fluids has shown that only the basic system of equations, including the empirical equation of state and the partial differential equations of mass, momentum, energy and matter transport, is characterized by a ten-parameter Galilean transformation group. An analysis of the complete solutions of the linearized system of fundamental equations for weakly dissipating media reveals a wide class of previously unknown singularly perturbed solutions supplementing well investigated regular solutions describing propagating waves. Fine flow components, whose geometry is typical for internal boundary layers that supplement the wave fields exist both at the boundaries and inside the volume of the liquid, are classified as linear precursors of shock waves. The calculated pattern of periodic internal waves beams covered with high-gradient envelopes agrees with data from independently performed experiments on measurements and visualization of the fine structure of linear and nonlinear waves in continuously stratified media.

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Cant, John P., and Brian W. McBride. "Mathematical analysis of the relationship between blood flow and uptake of nutrients in the mammary glands of a lactating cow." Journal of Dairy Research 62, no. 3 (August 1995): 405–22. http://dx.doi.org/10.1017/s0022029900031113.

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SummaryA dynamic mathematical model of blood flow regulation in the mammary glands of a lactating cow was constructed from a principle of local vasodilator release in response to changes in intracellular adenylate charge. An equation was derived to predict uptake of the milk precursors acetate, glucose, amino acids and fatty acids, as affected by mammary blood flow rate. Metabolism of the precursors to milk components and CO2 was simulated with a set of empirically derived equations. Relative rates of ATP production and utilization regulated both the number of perfused capillaries and the conductance of arteriolar segments in the mammary glands. The model simulated local control phenomena of functional and reactive hyperaemia, and simulation of autoregulation under changing arterial pressure suggested a predominance of precapillary sphincter regulation. It was predicted that an increase in blood flow without the mammary capacity to utilize blood metabolites efficiently would be detrimental to milk synthesis. Conversely, increased blood flow through changes in mammary activity resulted in predictions of higher milk production. It was proposed that the equation for uptake,be used in analysis of mammary arteriovenous differences.

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Passolunghi, M. Chiara, Irene C. Mammarella, and Gianmarco Altoè. "Cognitive Abilities as Precursors of the Early Acquisition of Mathematical Skills During First Through Second Grades." Developmental Neuropsychology 33, no. 3 (April 24, 2008): 229–50. http://dx.doi.org/10.1080/87565640801982320.

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Assel, Mike A., Susan H. Landry, Paul Swank, Karen E. Smith, and Laura M. Steelman. "Precursors to Mathematical Skills: Examining the Roles of Visual-Spatial Skills, Executive Processes, and Parenting Factors." Applied Developmental Science 7, no. 1 (January 2003): 27–38. http://dx.doi.org/10.1207/s1532480xads0701_3.

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Finocchiaro, Claudio, Germana Barone, Paolo Mazzoleni, Caterina Sgarlata, Isabella Lancellotti, Cristina Leonelli, and Marcello Romagnoli. "Artificial neural networks test for the prediction of chemical stability of pyroclastic deposits-based AAMs and comparison with conventional mathematical approach (MLR)." Journal of Materials Science 56, no. 1 (September 16, 2020): 513–27. http://dx.doi.org/10.1007/s10853-020-05250-w.

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Abstract The investigation on the reticulation degree of volcanic alkali-activated materials, AAMs, were experimentally determined in terms of chemico-physical properties: weight loss after leaching test in water, ionic conductivity and pH of the leachate and compressive strength. Artificial neural network (ANN) was successfully applied to predict the chemical stability of volcanic alkali-activated materials. Nine input data per each chemico-physical parameter were used to train each ANN. The training series of specific volcanic precursors were tested also for the other one. Excellent correlations between experimental and calculated data of the same precursor type were found reaching values around one. The evidence of strong effect on chemical stability of the alkaline activator SiO2/Na2O molar ratio as well as the Si/Al ratio of precursor mixtures on the reticulation degree of ghiara-based formulation with respect to volcanic ash-based materials is presented. It must be noted that such effect was much less pronounced on the compressive strength values, appearing more insensitive the molar ratio of the alkaline activator. The comparison of the ANN results with more conventional multiple linear regression (MLR) testifies the higher prediction performance of the first method. MLRs results, less significant, are useful to confirm the powerful capacity of ANNs to identify the more suitable formulation using a set of experimental AAMs. This study, as few others, on the correlation between chemical stability and compressive strength of AAMs provide a great contribution in the direction of durability and in-life mechanical performance of these class of materials. Graphic abstract

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Passolunghi, Maria Chiara, and Silvia Lanfranchi. "Domain-specific and domain-general precursors of mathematical achievement: A longitudinal study from kindergarten to first grade." British Journal of Educational Psychology 82, no. 1 (June 22, 2011): 42–63. http://dx.doi.org/10.1111/j.2044-8279.2011.02039.x.

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Khalimonchuk, V. A. "Mid-Weighed Kinetic Parameters for Use in the Two-Group Diffusion Model of Reactor Dynamics with Fuel Based on a Mixture of Fission Isotopes." Nuclear and Radiation Safety, no. 1(81) (March 12, 2019): 58–61. http://dx.doi.org/10.32918/nrs.2019.1(81).10.

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In the model of reactor kinetics based on the description of neutron transport in the two-group diffusion approximation, the number of equations describing the change in the concentration of delayed neutron precursors depends not only on the number of groups of delayed neutrons, but also on the number of fissile isotopes present in nuclear fuel. Since each isotope is characterized by six groups of delayed neutrons, the total number of differential equations describing concentrations of delayed neutron precursors is equal to the product of the number of fissile isotopes (M) and the number of groups of delayed neutrons for each isotope (i = 6). This is true provided that the decay constant of the concentrations of delayed neutron precursors that were formed from the division by fast or thermal neutrons can be taken in the same way. In fact, there is a difference, though small, in these values for the two energy groups. Therefore, the number of the corresponding equations is twice as high. In this paper, a mathematical expression is obtained for the weighted average decay constant of delayed neutron predecessors from fission by fast and thermal neutrons in a multiplying medium with several fissile isotopes. This, together with the conventional procedure of weighing the fraction of delayed neutrons from fission by fast or thermal neutrons in a similar multiplying medium, allows the two-group diffusion model of the reactor kinetics to be limited to only six equations for the concentrations of delayed neutron precursors and thus the kinetic model of the reactor to be simplified.

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Razanov, S. F., O. P. Tkachuk, O. M. Bakhmat, and A. M. Razanova. "Reducing danger of heavy metals accumulation in winter wheat grain which is grown after leguminous perennial precursor." Ukrainian Journal of Ecology 10, no. 1 (March 10, 2020): 254–60. http://dx.doi.org/10.15421/2020_40.

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Goal. Assessment of the influence of growing leguminous perennial herbs on the intensity of heavy metals accumulation in winter wheat as in a subsequent crop rotation. Methods. Field, laboratory atomic absorption method, mathematical and statistical processing. Results. cultivation of winter wheat after precursors of Medicago sativa I., Trifolium pratense L., Onobrychis arenaria Kit., Melilotus albus L., Lotus corniculatus L. or Galéga orientalis Lam. leads to a decrease in the content of lead by 1.8-2.5 times, cadmium – by 1.7–2.6 times, copper - 2.2–4.6 times and zinc - 1.6–1.9 times compared to winter wheat after corn precursor on silage. To obtain winter wheat with a minimum lead and copper content, the optimal precursor is Onobrychis arenaria Kit., with a minimum cadmium content - Galéga orientalis Lam. precursor, with a minimum copper and zinc content - the Trifolium precursorpratense L. The lowest influence on the reduction of heavy metals accumulation in winter wheat grain is caused by the precursor Lotus corniculatus L. Thanks to the use of leguminous perennial herbs as a precursor to winter wheat, it is possible to reduce the accumulation coefficient of heavy metals by 1.1-2.9 times compared with the corn precursor on silage. The lowest accumulation coefficient of the studied heavy metals was observed after the precursor of Medicago sativa I. Conclusion. Leguminous perennial herbs - Medicago sativa I., Trifolium pratense L., Onobrychis arenaria Kit., Melilotus albus L., Lotus corniculatus L. and Galega orientalis Lam. promote optimization of soil condition by increasing the content of humus, minerals nutrients, optimization of soil acidity. As a result, they reduce the accumulation of heavy metals (lead, cadmium, copper, and zinc) in winter wheat as the next crop in crop rotation and contribute to the reduction of accumulation coefficient of heavy metals in winter wheat.

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Kelleher, J. K. "Gluconeogenesis from labeled carbon: estimating isotope dilution." American Journal of Physiology-Endocrinology and Metabolism 250, no. 3 (March 1, 1986): E296—E305. http://dx.doi.org/10.1152/ajpendo.1986.250.3.e296.

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To estimate the rate of gluconeogenesis from steady-state incorporation of labeled 3-carbon precursors into glucose, isotope dilution must be considered so that the rate of labeling of glucose can be quantitatively converted to the rate of gluconeogenesis. An expression for the value of this isotope dilution can be derived using mathematical techniques and a model of the tricarboxylic acid (TCA) cycle. The present investigation employs a more complex model than that used in previous studies. This model includes the following pathways that may affect the correction for isotope dilution: 1) flux of 3-carbon precursor to the oxaloacetate pool via acetyl-CoA and the TCA cycle; 2) flux of 4- or 5-carbon compounds into the TCA cycle; 3) reversible flux between oxaloacetate (OAA) and pyruvate and between OAA and fumarate; 4) incomplete equilibrium between OAA pools; and 5) isotope dilution of 3-carbon tracers between the experimentally measured pool and the precursor for the TCA-cycle OAA pool. Experimental tests are outlined which investigators can use to determine whether these pathways are significant in a specific steady-state system. The study indicated that flux through these five pathways can significantly affect the correction for isotope dilution. To correct for the effects of these pathways an alternative method for calculating isotope dilution is proposed using citrate to relate the specific activities of acetyl-CoA and OAA.

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Konstantaras, A., G. N. Fouskitakis, J. P. Makris, and F. Vallianatos. "Stochastic analysis of geo-electric field singularities as seismically correlated candidates." Natural Hazards and Earth System Sciences 8, no. 6 (December 18, 2008): 1451–62. http://dx.doi.org/10.5194/nhess-8-1451-2008.

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Abstract. The study of the Earth's electromagnetic field prior to the occurrence of strong seismic events has repeatedly revealed cases where transient electric potential anomalies, often deemed as possible earthquake precursors, were observed on electromagnetic field recordings. In an attempt to understand the nature of such signals, several models have been proposed based upon the exhibited characteristics of the observed anomalies, often supported by different mathematical models simulating possible generation mechanisms. This paper discusses a candidate Electric Earthquake Precursor (EEP) signal, accompanying the Kythira Mw=6.9 earthquake in Greece (occurred on 8 January 2006). Neuro-Fuzzy along with stochastic models are currently incorporated for the modelling and analysis of the recorded Earth's electric field. The results of the study indicate that the Neuro-Fuzzy model treats the observed possible EEP signal as an external additive component to the recorded Earth's electric field, while the stochastic TARMA models accurately represent the recorded electric signals in both the time and the frequency domains. The complementary findings of both methodologies might potentially contribute to the future development of a more accurate and generalized framework for the efficient recognition and characterization of possible EEP's.

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Taskesen, Teoman, Devendra Pareek, David Nowak, Willi Kogler, Thomas Schnabel, Erik Ahlswede, and Levent Gütay. "Potential of CZTSe Solar Cells Fabricated by an Alloy-Based Processing Strategy." Zeitschrift für Naturforschung A 74, no. 8 (August 27, 2019): 673–82. http://dx.doi.org/10.1515/zna-2019-0136.

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AbstractIn this manuscript, we give an overview of the main insights into our growth procedure for kesterite solar cells and show the possibilities that are provided by this approach. The importance of using Cu–Sn alloy instead of elemental Sn and Cu in the precursor is shown. We discuss how the alloy approach stabilises the composition and helps guide the process along a preferred reaction pathway. A summary of our previously reported findings in the context of our latest results on kesterite solar cells prepared from Cu–Sn alloyed precursors is drawn. The positive impact of an alloy precursor configuration on the formation pathway, process control, and process resilience is demonstrated. Furthermore, a new optimisation strategy for kesterite, based on the reported pathway, is discussed, including a smooth phase transition from Cu-rich to Cu-poor kesterite. Finally, we demonstrate results on buffer optimisation and the application of a promising hybrid buffer configuration of CdS/Zn(O,S), which can reduce the optical losses in the solar cell structure.

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Claire, M., J. L. Steimer, M. E. Oblin, H. P. Gaeggeler, A. Venot, P. Corvol, and B. C. Rossier. "Cytoplasmic and nuclear uptake of aldosterone in toad bladder: a mathematical modeling approach." American Journal of Physiology-Cell Physiology 248, no. 1 (January 1, 1985): C88—C101. http://dx.doi.org/10.1152/ajpcell.1985.248.1.c88.

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The mechanism of aldosterone uptake in the epithelial cells of toad bladder was studied using mathematical modeling. Two complementary approaches were used. The first involved analysis of cytosolic aldosterone binding at steady state according to models defined by the sum of independent noninteractive binding sites. The best model describing the experimental data corresponded to two specific binding sites with mean dissociation constant values of 0.20 and 60 nM for types 1 and 2, respectively. The second approach was based on the analysis of cytoplasmic and nuclear aldosterone uptake kinetics at 25 and 0 degrees C in intact bladder. Two models (A and B) were studied. They both implied the existence of two types of aldosterone binding sites as precursors of the corresponding chromatin bound complexes. In model A, nuclear translocation of the two types of receptors was assumed to obey first-order kinetics. In model B, the translocation process for type 1 sites involved a time lag leading to delayed binding to chromatin. Both models were found to fit the experimental data satisfactorily. The fit obtained for model B appeared to be better at low aldosterone concentrations.

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Ahmed, Hesham M., Abdel-Hady A. El-Geassy, Nurni Neelakantan Viswanathan, and Seshadri Seetharaman. "Kinetics and Mathematical Modeling of Hydrogen Reduction of NiO–WO₃ Precursors in Fluidized Bed Reactor." ISIJ International 51, no. 9 (2011): 1383–91. http://dx.doi.org/10.2355/isijinternational.51.1383.

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NAHORNYI, VOLODYMYR, ANTON PANDA, VALENTINO STRASER, and IVETA PANDOVA. "FORECASTING AN VIBRATION BY MONITORING THE DYNAMICS OF CHANGES ITS PRECURSORS OF VARIOUS PHYSICAL NATURE." MM Science Journal 2021, no. 2 (June 2, 2021): 4396–99. http://dx.doi.org/10.17973/mmsj.2021_6_2021019.

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Prediction crosses all fields of Science, being itself the evident manifestation of the Scientific Method. This study addresses the delicate aspect of vibration forecasting, which considers the association and interaction between the variables involved, such as radio anomalies, the proton density of the solar wind preceding strong vibration. The analysis is based on the collection of about 800 data of vibration of range equal to or greater than 6 occurred on a global scale between 2012 and 2014, related to solar wind and radio anomalies detected before the disastrous Tohoku vibration of March 11, 2011. To discuss the data has been applied the deductive logic, which allows to make predictions from the hypotheses, formulated in a mathematical way. In this context, the mechanisms of triggering vibration are hypothesized with an interaction of electrical nature, at subatomic scale. The outcome of the research has shown encouraging results on the application of the prediction formula, reinforced by the control of its parameters.

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Sofroniou, Anastasia, Bhairavi Premnath, and Kevin Jagadissen Munisami. "An Insight into the Dynamical Behaviour of the Swing Equation." WSEAS TRANSACTIONS ON MATHEMATICS 22 (January 25, 2023): 70–78. http://dx.doi.org/10.37394/23206.2023.22.9.

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Motivated by the nonlinear dynamics of mathematical models encountered in power systems, an investigation into the dynamical behaviour of the swing equation is carried out. This paper examines analytically and numerically the development of oscillatory periodic solutions, whereby increases of the control parameter, lead to a cascade of period doubling bifurcations, before eventually loss in stability is exhibited and effective forerunners to chaos revealed. Gaining an understanding on the dynamical behaviour of the system can help to produce a deeper insight of the bifurcations entailed, with the appearance of the triggered sequence of the first period doubling’s acting as precursors of imminent danger and difficult operations of a practical system.

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Bauer, G. E. W. "Precursors of the excitonic insulator in excited quantum wells." Physica Scripta T45 (January 1, 1992): 154–57. http://dx.doi.org/10.1088/0031-8949/1992/t45/032.

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ZHOU, WEI-XING, and DIDIER SORNETTE. "NONPARAMETRIC ANALYSES OF LOG-PERIODIC PRECURSORS TO FINANCIAL CRASHES." International Journal of Modern Physics C 14, no. 08 (October 2003): 1107–25. http://dx.doi.org/10.1142/s0129183103005212.

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We apply two nonparametric methods to further test the hypothesis that log-periodicity characterizes the detrended price trajectory of large financial indices prior to financial crashes or strong corrections. The term "parametric" refers here to the use of the log-periodic power law formula to fit the data; in contrast, "nonparametric" refers to the use of general tools such as Fourier transform, and in the present case the Hilbert transform and the so-called (H, q)-analysis. The analysis using the (H, q)-derivative is applied to seven time series ending with the October 1987 crash, the October 1997 correction and the April 2000 crash of the Dow Jones Industrial Average (DJIA), the Standard & Poor 500 and Nasdaq indices. The Hilbert transform is applied to two detrended price time series in terms of the ln (tc-t) variable, where tcis the time of the crash. Taking all results together, we find strong evidence for a universal fundamental log-frequency f=1.02±0.05 corresponding to the scaling ratio λ=2.67±0.12. These values are in very good agreement with those obtained in earlier works with different parametric techniques. This note is extracted from a long unpublished report with 58 figures available at , which extensively describes the evidence we have accumulated on these seven time series, in particular by presenting all relevant details so that the reader can judge for himself or herself the validity and robustness of the results.

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Huo, Xiaoxu, Jing Li, Yun-Feng Cao, Sai-Nan Li, Ping Shao, Junhong Leng, Weiqin Li, et al. "Trimethylamine N-Oxide Metabolites in Early Pregnancy and Risk of Gestational Diabetes: A Nested Case-Control Study." Journal of Clinical Endocrinology & Metabolism 104, no. 11 (August 2, 2019): 5529–39. http://dx.doi.org/10.1210/jc.2019-00710.

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Abstract Objectives This study aimed to investigate the associations between trimethylamine N-oxide (TMAO) and related metabolites in early pregnancy and the risk of gestational diabetes mellitus (GDM). Design A prospective cohort of 22,302 pregnant women from 2010 to 2012 in Tianjin, China, was used to perform a nested case-control study. A total of 243 women with GDM and 243 women without GDM matched by maternal age (±1 year) were used as cases and controls, respectively. Conditional logistic regression and restricted cubic spline were used to examine the full-range risk associations between individual TMAOs metabolites at the first antenatal care visit with GDM. Trimethylamine conversion ratio (TMAR) was defined as trimethylamine (TMA)/its precursors, and trimethylamine N-oxide conversion ratio (TMAOR) was defined as TMAO/TMA. An additive interaction between high TMAR and low TMAOR indicates a state of TMA accumulation, and a mathematical interaction between high TMAR and high TMAOR indicates accumulation of TMAO. Results TMA was linearly associated with GDM, whereas TMA precursors and TMAO were inversely associated with GDM with clear threshold effects, i.e., 16 nmol/mL for TMAO, 200 nmol/mL for betaine, 112 nmol/mL for l-carnitine, and 110 and 270 nmol/mL for cholinechloride (a U-shaped relationship). Copresence of TMAR >0.35 and TMAOR ≤0.15 was associated with a markedly higher OR (11.16; 95% CI, 5.45 to 22.8), compared with TMAR >0.35 only (OR = 1.71; 95% CI, 0.42 to 6.95) or TMAOR ≤0.15 only (OR = 2.06; 95% CI, 1.09 to 3.90), with a significant additive interaction. However, the mathematical interaction was nonsignificant. Conclusions TMAO metabolites in the early pregnancy were associated with the risk of GDM, whereas TMA was more likely to play a causal role in GDM.

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Tournus, Magali, Miguel Escobedo, Wei-Feng Xue, and Marie Doumic. "Insights into the dynamic trajectories of protein filament division revealed by numerical investigation into the mathematical model of pure fragmentation." PLOS Computational Biology 17, no. 9 (September 3, 2021): e1008964. http://dx.doi.org/10.1371/journal.pcbi.1008964.

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The dynamics by which polymeric protein filaments divide in the presence of negligible growth, for example due to the depletion of free monomeric precursors, can be described by the universal mathematical equations of ‘pure fragmentation’. The rates of fragmentation reactions reflect the stability of the protein filaments towards breakage, which is of importance in biology and biomedicine for instance in governing the creation of amyloid seeds and the propagation of prions. Here, we devised from mathematical theory inversion formulae to recover the division rates and division kernel information from time dependent experimental measurements of filament size distribution. The numerical approach to systematically analyze the behaviour of pure fragmentation trajectories was also developed. We illustrate how these formulae can be used, provide some insights on their robustness, and show how they inform the design of experiments to measure fibril fragmentation dynamics. These advances are made possible by our central theoretical result on how the length distribution profile of the solution to the pure fragmentation equation aligns with a steady distribution profile for large times.

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Gemming, Sibylle, Matthias Lehmann, and Gotthard Seifert. "Semi-flexible star-shaped molecules: conformational analysis of nano-segregated mesogens forming columnar liquid-crystal phases." International Journal of Materials Research 96, no. 9 (January 1, 2005): 988–97. http://dx.doi.org/10.1515/ijmr-2005-0172.

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Abstract The structural prerequisites are investigated, which make star-shaped molecules suitable precursors for the formation of columnar liquid-crystalline phases. Electronic structure calculations on smaller mesogens show that not all conformers exhibit the atomistic structure, the stability against distortion, and additional dipole moments, which favour columnar stacking. For the presently studied compounds with short terminating alkyl chains, the calculations indicate that the steric factor becomes dominant with increasing star size. Thus, the optimised geometric structures were employed to generate a simplified mathematical model of the structures, which accounts only for the steric interaction in the larger stars. With the help of these diagrams, the most common conformers of star-shaped molecules can be derived in a systematic fashion.

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Sorariutta, Anne, and Maarit Silvén. "Maternal cognitive guidance and early education and care as precursors of mathematical development at preschool age and in ninth grade." Infant and Child Development 27, no. 2 (November 12, 2017): e2069. http://dx.doi.org/10.1002/icd.2069.

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Van der Kloot, William. "Lord Justice of Appeal John Fletcher Moulton and explosives production in World War I: ‘the mathematical mind triumphant’." Notes and Records: the Royal Society Journal of the History of Science 68, no. 2 (December 18, 2013): 171–86. http://dx.doi.org/10.1098/rsnr.2013.0056.

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At the end of November 1914 Lord Moulton (1844–1921) became the director of explosives production in the War Office. A 70-year-old jurist may seem an extraordinary choice, but he was an extraordinary man. He was Senior Wrangler at Cambridge, was elected to the Royal Society for research on electricity, and learned about chemistry as a barrister for dye and explosives manufacturers. He assembled an able team of administrators and chemists who designed and managed mammoth new national explosives factories. They could not make enough TNT and picric acid from obtainable precursors, so Moulton persuaded the reluctant armed services to adopt mixtures of TNT and ammonium nitrate, which enabled them to make even more than was needed. In mid-1915 they moved to the new Ministry of Munitions, where they also became responsible for fertilizers and poison gases. In 1917 they produced explosives at a higher rate than was attained in World War II.

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SORNETTE, D., F. FERRÉ, and E. PAPIERNIK. "MATHEMATICAL MODEL OF HUMAN GESTATION AND PARTURITION: IMPLICATIONS FOR EARLY DIAGNOSIS OF PREMATURITY AND POSTMATURITY." International Journal of Bifurcation and Chaos 04, no. 03 (June 1994): 693–99. http://dx.doi.org/10.1142/s0218127494000484.

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Knowledge of precursors and predictors of human parturition would be important both for our understanding of the controlling mechanisms and for practical use in the detection and diagnosis of various abnormalities of the birth process. They involve a multitude of genetic, metabolic, nutritional, hormonal and environmental factors. Present research is however hindered by the lack of a clear recognized correlation between the time evolution of these various variables and the initiation of parturition. Here, we propose a coherent logical framework which allows us to rationalize the various laboratory and clinical observations on maturation, the triggering mechanisms of parturition, the existence of various abnormal patterns as well as the effect of external stimuli of various kinds. Within the proposed mathematical model, parturition is seen as a ”critical” instability or phase transition from a state of quietness, characterized by a weak incoherent activity of the uterus in its various parts as a function of time (state of activity of many small incoherent intermittent oscillators), to a state of globally coherent contractions where the uterus functions as a single macroscopic oscillator. Our approach gives a number of new predictions and suggests a strategy for future research and clinical studies, which present interesting potentials for improvements in predicting methods and in describing various abnormal prenatal situations.

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Liu, Xinxing, Ruiting Hao, Qichen Zhao, Faran Chang, Yong Li, Kang Gu, Lu Wang, Bin Liu, and Jie Guo. "Studies on Sputtered Cu–Zn–Sn–O Precursor to Fabricate Cu2ZnSnS4 Thin Films." Zeitschrift für Naturforschung A 73, no. 10 (October 25, 2018): 957–64. http://dx.doi.org/10.1515/zna-2018-0177.

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AbstractThe Cu2ZnSnS4 (CZTS) thin films were fabricated by sulfurization of radiofrequency magnetron sputtered Cu–Zn–Sn–O (CZTO) precursors. Here, we extend recent works in the field of fabricating CZTO precursors by a new approach sputtering ZnO/Sn/Cu targets. The effects of one-step and two-step annealing processes applied for CZTO precursors on the structure, morphology, optical, and electrical properties were investigated systematically. The preannealing step of fundamental phase formation in the sulfurization process was also discussed. The two-step annealing process was found to affect the composition of element Sn slightly but significantly improved crystallinity, CZTS/Mo interfacial conditions, surface roughness, and electrical properties. The two-step annealed CZTS thin films had excellent optical and electrical properties with an optical band gap of 1.51 eV, a hole concentration of 2.4 × 1017 cm−3, and a hole mobility of 1.97 cm2/(V⋅s). In addition, the CZTS/Mo interface with small grains and voids were significantly improved. CZTS-based solar cell devices were successfully fabricated. The characteristics of current–voltage (J–V) curves indicated that short-circuit currents had a tendency to increase with the improvement of CZTS/Mo interface and surface morphology. As a result, the device based on two-step annealed CZTS thin films exhibited better performance with an open-circuit voltage of 553 mV, short-circuit current of 7.2 mA⋅cm−2, a fill factor of 37.8%, and a conversion efficiency of 1.51%.

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Jin, Tiantian, Lei Wang, Yuguang Zhao, and Luming Shen. "Variation Characteristics Mathematical Calculation of O₃ and Its Relationship with Meteorological Factors by Big Data Technology." Journal of Physics: Conference Series 2083, no. 3 (November 1, 2021): 032001. http://dx.doi.org/10.1088/1742-6596/2083/3/032001.

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Abstract Based on the data of environmental monitoring stations and meteorological stations in Qinhuangdao from May 2017 to May 2020, the variation characteristics of O3 and precursors (NO2 and CO) as well as their relationship with meteorological elements were analyzed. The results showed that the daily average concentration of O3-8 h in Qinhuangdao increased year by year. The monthly average concentration of O3-8 h was high in summer and low in winter, and the peak appeared in June. The diurnal variation of O3 concentration was unimodal structure, and the concentration increased in the afternoon, but it decreased at night. The concentration of NO2 and CO was inversely correlated with O3, and the peak value of NO2 in March could be related to frequent cold air activity and increased burning of loose coal. The meteorological elements favorable for the occurrence of ozone pollution weather in Chengde were total solar radiation irradiance greater than 1000W/m2, the daily maximum temperature greater than 33 °C, and the daily minimum relative humidity less than 40% and 65%∽80%, southerly wind or southwest wind.

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Wodarz, Dominik, and Martin A. Nowak. "Correlates of cytotoxic T–lymphocyte–mediated virus control: implications for immuno–suppressive infections and their treatment." Philosophical Transactions of the Royal Society of London. Series B: Biological Sciences 355, no. 1400 (August 29, 2000): 1059–70. http://dx.doi.org/10.1098/rstb.2000.0643.

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A very important question in immunology is to determine which factors decide whether an immune response can efficiently clear or control a viral infection, and under what circumstances we observe persistent viral replication and pathology. This paper summarizes how mathematical models help us gain new insights into these questions, and explores the relationship between antiviral therapy and long–term immunological control in human immunodeficiency virus (HIV) infection. We find that cytotoxic Tlymphocyte (CTL) memory, defined as antigen–independent persistence of CTL precursors, is necessary for the CTL response to clear an infection. The presence of such a memory response is associated with the coexistence of many CTL clones directed against multiple epitopes. If CTL memory is inefficient, then persistent replication can be established. This outcome is associated with a narrow CTL response directed against only one or a few viral epitopes. If the virus replicates persistently, occurrence of pathology depends on the level of virus load at equilibrium, and this can be determined by the overall efficacy of the CTL response. Mathematical models suggest that controlled replication is reflected by a positive correlation between CTLs and virus load. On the other hand, uncontrolled viral replication results in higher loads and the absence of a correlation between CTLs and virus load. A negative correlation between CTLs and virus load indicates that the virus actively impairs immunity, as observed with HIV. Mathematical models and experimental data suggest that HIV persistence and pathology are caused by the absence of sufficient CTL memory. We show how mathematical models can help us devise therapy regimens that can restore CTL memory in HIV patients and result in long–term immunological control of the virus in the absence of life–long treatment.

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McBean, Edward, Zoe Zhu, and Wen Zeng. "Modeling formation and control of disinfection byproducts in chlorinated drinking waters." Water Supply 10, no. 5 (December 1, 2010): 730–39. http://dx.doi.org/10.2166/ws.2010.269.

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While disinfection of drinking water reduces the risks of pathogenic infection, threats to human health due to the formation of disinfection byproducts (DBPs) may arise due to natural organic precursors. Regression-based models characterizing the formation of DBPs are derived from data for 28 conventional water treatment plants in Ontario. DBPs are shown to be correlated statistically with dissolved organic carbon, pre-and post-chlorination dosages, pH and temperature. Using backward elimination nonlinear regression, a set of mathematical functions are obtained (R2=0.62 to 0.79) for an array of DBPs. The models are used to guide decision-markers in the selection and operation of drinking water treatment processes to decrease DBP formation, indicating that a shift from emphasis on pre-chlorination to post-chlorination has the most effect on DBP formation.

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IFANTIS, A., and S. PAPADIMITRIOU. "SUPPORT VECTOR IDENTIFICATION OF SEISMIC ELECTRIC SIGNALS." International Journal of Pattern Recognition and Artificial Intelligence 17, no. 04 (June 2003): 545–65. http://dx.doi.org/10.1142/s0218001403002484.

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Traditional pattern recognition approaches usually generalize poorly on difficult tasks as the problem of identification of the Seismic Electric Signals (SES) electrotelluric precursors for earthquake prediction. This work demonstrates that the Support Vector Machine (SVM) can perform well on this application. The a priori knowledge consists of a set of VAN rules for SES signal detection. The SVM extracts implicitly these rules from properly preprocessed features and obtains generalization performance founded upon a robust mathematical basis. The potentiality of obtaining generalization potential even in feature spaces of high dimensionality bypasses the problems due to overtraining of the conventional machine learning architectures. The paper considers the optimization of the generalization performance of the SVM. The results indicate that the SVM outperforms many alternative computational intelligence models for the task of SES pattern recognition.

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Papa, Tiffany. "Effects of Higher Order Questioning in Prekindergarten for School Readiness." Journal of Educational and Developmental Psychology 10, no. 2 (June 10, 2020): 25. http://dx.doi.org/10.5539/jedp.v10n2p25.

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This study investigated whether the strategy of higher order questioning during interest area time would have a positive effect on kindergarten school readiness (specifically focusing on mathematical and language concepts) for students in a low-socioeconomic area school. Evidence from the Developmental Indicators for the Assessment of Learning/ Third Edition (DIAL-3) scores (completed upon entering kindergarten) establishes that the students in this low-socioeconomic area school were not kindergarten ready. Statistical analyses concurred that increasing the frequency of higher order questioning during interest area time significantly improves the test performance of students within the mathematical and language concepts area of the DIAL-3 assessment. The student achievement results of providing teacher training in higher-order questioning techniques during interest area time (the most vital learning time of the prekindergarten day) has provided evidence of increased cognitive development, ultimately increasing student achievement in mathematical and language skills. High-quality prekindergarten services involving best practices are the precursors for kindergarten; therefore, improving teacher-child verbal interactions in prekindergarten ultimately addresses the issue of kindergarten school readiness. Additional findings included a correlation indicating that the students who did well in Language skills also did well in Mathematics and a statistically significant correlation existed between better scores and positive behavior. It is anticipated that the contributions of the present study will encourage future research that will continue to elaborate upon the effects of higher order questioning at the prekindergarten level on kindergarten school readiness.

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Eftaxias, K. A., P. G. Kapiris, G. T. Balasis, A. Peratzakis, K. Karamanos, J. Kopanas, G. Antonopoulos, and K. D. Nomicos. "Unified approach to catastrophic events: from the normal state to geological or biological shock in terms of spectral fractal and nonlinear analysis." Natural Hazards and Earth System Sciences 6, no. 2 (April 3, 2006): 205–28. http://dx.doi.org/10.5194/nhess-6-205-2006.

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Abstract. An important question in geophysics is whether earthquakes (EQs) can be anticipated prior to their occurrence. Pre-seismic electromagnetic (EM) emissions provide a promising window through which the dynamics of EQ preparation can be investigated. However, the existence of precursory features in pre-seismic EM emissions is still debatable: in principle, it is difficult to prove associations between events separated in time, such as EQs and their EM precursors. The scope of this paper is the investigation of the pre-seismic EM activity in terms of complexity. A basic reason for our interest in complexity is the striking similarity in behavior close to irreversible phase transitions among systems that are otherwise quite different in nature. Interestingly, theoretical studies (Hopfield, 1994; Herz and Hopfield 1995; Rundle et al., 1995; Corral et al., 1997) suggest that the EQ dynamics at the final stage and neural seizure dynamics should have many similar features and can be analyzed within similar mathematical frameworks. Motivated by this hypothesis, we evaluate the capability of linear and non-linear techniques to extract common features from brain electrical activities and pre-seismic EM emissions predictive of epileptic seizures and EQs respectively. The results suggest that a unified theory may exist for the ways in which firing neurons and opening cracks organize themselves to produce a large crisis, while the preparation of an epileptic shock or a large EQ can be studied in terms of ''Intermittent Criticality''.

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Journal articles on the topic 'Mathematical precursors'

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