Clarifying tetrapod embryogenesis, a physicist's point of view

In this paper, we will introduce a generalized soldering p-forms geometry, which can be the right framework to describe many new approaches and concepts in modern physics. Here we will treat some aspects of the theory of local cohomology in fields theory or more precisely the theory of soldering-form conservation laws in physics. We provide some illustrative applications, primarily taken from the Einstein equations of general theory of relativity and Yang–Mills theory. This theory can be considered to be a generalization of Noether's theory of conserved current to differential forms of any degree. An essential result of this, is that the conservation of the energy–momentum in general relativity, is linked to the fact that the vacuum field equations are equivalent to the integrability conditions of a first-order system of differential equations. We also apply the idea of the soldered space and the integrability conditions to the case of Yang–Mills theory. The mathematical framework, where these intuitive considerations would fit naturally, can be used to describe also the dynamics of changing manifolds.

Invariance properties and conservation laws of the nonlinear damped wave equation with power law nonlinearities

This work proposes an approach for latent dynamics learning that exactly enforces physical conservation laws. The method comprises two steps. First, we compute a low-dimensional embedding of the high-dimensional dynamical-system state using deep convolutional autoencoders. This defines a low-dimensional nonlinear manifold on which the state is subsequently enforced to evolve. Second, we define a latent dynamics model that associates with a constrained optimization problem. Specifically, the objective function is defined as the sum of squares of conservation-law violations over control volumes in a finite-volume discretization of the problem; nonlinear equality constraints explicitly enforce conservation over prescribed subdomains of the problem. The resulting dynamics model—which can be considered as a projection-based reduced-order model—ensures that the time-evolution of the latent state exactly satisfies conservation laws over the prescribed subdomains. In contrast to existing methods for latent dynamics learning, this is the only method that both employs a nonlinear embedding and computes dynamics for the latent state that guarantee the satisfaction of prescribed physical properties. Numerical experiments on a benchmark advection problem illustrate the method's ability to significantly reduce the dimensionality while enforcing physical conservation.

Learning a latent-dynamics model for complex real-world physical processes is indispensable. Most previous latent-dynamics modeling approaches suffer from the violation of important physical properties such as conservation.

On the adoption of velocity variable and grid system for fluid flow computation in curvilinear coordinates

This paper uses a new decomposition of the fluid velocity in terms of a large-scale continuous component with respect to time and a small-scale non continuous random component. Within this general framework, a stochas-tic representation of the Reynolds transport theorem and Navier-Stokes equations can be derived, based on physical conservation laws. This physically relevant stochas-tic model is applied in the context of the POD-Galerkin method. In both the stochastic Navier-Stokes equation and its reduced model, a possibly time-dependent, inhomoge-neous and anisotropic diffusive subgrid tensor appears naturally and generalizes classical subgrid models. We proposed two ways of estimating its parametrization in the context of POD-Galerkin. This method has shown to be able to successfully reconstruct energetic Chronos for a wake flow at Reynolds 3900, whereas standard POD-Galerkin diverged systematically.

Integrated breakup modeling solutions from debrisat analysis

A simple coolant blowdown model for the evaluation of safety problems in water-cooled reactors with pressure vessels

An overview of the theory of photoelectron angular distributions for atoms is presented. Its features, which are embodied in a single asymmetry parameter $\ensuremath{\beta}$ in the electric dipole approximation, are examined within the framework of the angular momentum transfer formulation. The $\ensuremath{\beta}$ parameter is in principle always energy dependent. Within the $\mathrm{LS}$ coupling approximation, however, there are instances, each representing a multitude of particular photoionization processes, in which $\ensuremath{\beta}$ is an analytically determined constant. The energy dependence of the $\ensuremath{\beta}$ parameters in such instances is due entirely to spin-orbit and other relativistic interactions. The study of the energy dependence of the $\ensuremath{\beta}$ parameter in these cases is thus of interest because it spotlights weak-interaction effects which are usually overwhelmed by stronger interactions. We illustrate the general predictions by a detailed consideration of the energy dependence of the $\ensuremath{\beta}$ parameter for $s$-subshell photoionization processes. It is shown that the asymmetry parameters for atomic $s$ subshells are particularly suitable for distinguishing between purely geometrical effects on the photoelectron angular distribution, resulting from physical conservation laws, and dynamical effects arising from relativistic interactions and electron exchange and correlation. In general, the $\ensuremath{\beta}$ parameters for $s$ subshells vary with energy; such variation is largest near minima in the cross sections for the corresponding photoelectron channels and in the vicinity of resonances. However, a number of atomic photoionization transitions are identified for which $\ensuremath{\beta}$ would be a constant (equal to one of the three values 2, $\frac{1}{5}$, or - 1) were it not for relativistic interactions and (in some cases) final-state interchannel coupling and/or initial-state electron correlations. Measurement or calculation of the $\ensuremath{\beta}$ parameters for such transitions thus provides a sensitive measure of the strength of relativistic interactions as well as of electron correlations.

In a flow including a free surface, an interaction relationship between objects and the free surface is seen in many cases. In recent years, research on environmental change and protection has become active, so analyzing a flow field including the free surface is one of the major issues in river engineering and marine engineering. However, in most of the previous researches, the flow field was limited to the reproduction of the simple flow field. In this study, we dealt with the flow field including the free surface around a moving object with a complicated shape. So, in order to show the change of the shape of the free surface caused by the moving object, the Interface Tracking method was adopted. In this method, in order to express how the interface moves, it is necessary to move and deform the computational grid. Therefore, the calculation method was constructed based on the Unstructured Moving-Grid Finite-Volume method, which strictly satisfies the geometric conservation law and the physical conservation law. The NACA0012 blade was placed under the free surface, and the relationship between the blade's movement and the free surface was investigated. As a result, it was confirmed that the detail change of the free surface caused by the movement of the blade. Thus, it could be shown the promising feature of the computation.

Gene imprinting is a widely observed epigenetic phenomenon in maize endosperm; however, whether it also occurs in the maize embryo remains controversial. Here, we used high-throughput RNA sequencing on laser capture microdissected and manually dissected maize embryos from reciprocal crosses between inbred lines B73 and Mo17 at six time points (3-13days after pollination, DAP) to analyze allelic gene expression patterns. Co-expression analysis revealed sequential gene activation during maize embryo development. Gene imprinting was observed in maize embryos, and a greater number of imprinted genes were identified at early embryo stages. Sixty-four strongly imprinted genes were identified (at the threshold of 9:1) on manually dissected embryos 5-13 DAP (more imprinted genes at 5 DAP). Forty-one strongly imprinted genes were identified from laser capture microdissected embryos at 3 and 5 DAP (more imprinted genes at 3 DAP). Furthermore, of the 56 genes that were completely imprinted (at the threshold of 99:1), 36 were not previously identified as imprinted genes in endosperm or embryos. In situ hybridization demonstrated that most of the imprinted genes were expressed abundantly in maize embryonic tissue. Our results shed lights on early maize embryo development and provide evidence to support that gene imprinting occurs in maize embryos.

A Physics-Informed Neural Network (PINN) was developed to solve the complex Navier-Stokes (N-S) equations for multiphase flow measurement including flowrates of individual phases in the multiphase mixture, and phase ratios. The results were compared against a mathematical based multiphase flow measurement approach and validated through a controlled loop test using oil, water, and gas. The PINN embeds fundamental fluid dynamics principles into its learning process, ensuring that the neural network adheres to the governing physical laws of motion, continuity, and conservation. Unlike traditional neural networks that rely solely on data-driven learning, PINNs incorporate fluid dynamics driven differential equations, to enhance model accuracy and reliability. This study evaluates the accuracy, efficiency, and repeatability of PINNs by comparing their results against traditional mathematical-based multiphase flow measurement (MPFM) technology and controlled test cases. The developed PINN successfully solved the Navier- Stokes (N-S) equations in their closest approximation to the original form, with minimal assumptions and simplifications, to estimate multiphase flow rates, integrating fundamental fluid dynamics principles into its learning process. The results demonstrated that the PINN-based approach achieved accuracy comparable to traditional mathematical multiphase flow measurement (MPFM) technologies, while significantly improving computational efficiency. During controlled loop tests with oil, water, and gas, the PINN model consistently captured flow dynamics with high precision, validating its effectiveness under real-world conditions. Moreover, the PINN method exhibited strong generalization capabilities, adapting to various flow regimes without the need for extensive empirical calibration. Compared to conventional MPFM technologies, PINN reduced reliance on predefined correlations and offered greater adaptability to changing fluid properties. The repeatability of results confirmed the model's reliability, positioning PINNs as a promising alternative for complex multiphase flow measurement applications. These findings highlight the potential of PINNs as an innovative, physics-guided, and data-efficient solution, effectively bridging the gap between traditional physics-based methods and modern machine learning techniques. This paper presents an innovative application of Physics-Informed Neural Networks (PINNs) for multiphase flow measurement, offering a data-driven yet physics-guided alternative to traditional mathematical MPFM technologies. By embedding fundamental physical laws into the neural network training process, the proposed approach enhances accuracy, computational efficiency, and adaptability, while minimizing reliance on extensive empirical calibration. This advancement significantly improves real-time flow monitoring, equipping practicing engineers with a more reliable, data-efficient, and scalable solution for complex multiphase flow measurement in industrial applications.

The current problem related to science education is that students seem to lack the interest and motivation towards science studies. Teaching modules that are based on socio-scientific issues (SSI) in science education have been found to be interesting and motivating for students. One way to begin with SSI modules is to use scenarios that combine science content with SSI by including, for example, everyday examples related to students’ life or societal issues. An ideal scenario is connected to SSI, supports students’ involvement and reflection, and stimulates students’ scientific questions. However, earlier studies have shown that teachers have concerns about creating motivating SSI scenarios. The data for this case study was gathered from Finnish teachers who designed 24 scenarios in total for their science classes. We applied deductive content analysis and typification in order to find what kind of scenarios the teachers planned and implemented. There were eight high-quality scenarios, which took the motivational socio-scientific context into account in a diverse manner, involved students in collective thinking and reflection on their prior knowledge, and stimulated open-ended scientific questions with multiple solutions. The majority of the scenarios were so-called mediocre scenarios (14), which included weakly motivational aspects related to the socio-scientific context, and the low-quality scenarios (2) which paid only little attention to them. Our findings indicate that it seems to be challenging but possible for science teachers to develop an SSI scenario that is interesting and motivational from students’ point of view.

THE paper read at Monday's meeting of the Royal Geographical Society was on Hudson's Bay and Hudson's Strait as anavigable channel, by Commander Markham. It was really a brief sketch of a much larger memoir on Hudson's Bay which Commander Markham has prepared, and which will ultimately be published by the Society. For some years investigations have been carried on with a view to discover whether the navigation of Hudson's Bay could be so depended on as to justify its acceptance as a regular trade route, in conjunction with a railway, to the more northerly parts of Canada. Commander Markham briefly sketches the history of navigation in Hudson's Bay, and concludes with the results of his own visit in the summer of 1886 on board the Alert. The result, he states, of all the experience gathered from voyages during two centuries, and from observations at the stations, is that Hudson's Strait is perfectly navigable and free from ice in August and later in the season. It must be remembered that this passage has been successfully accomplished nearly every year for the last two centuries, while the vessels that have been employed on the service have been ordinary sailing-ships, dependent entirely on wind and weather. It is very rare indeed that they have failed to get through, and still more rare that any of them have been destroyed by the ice. It appears from the official records of the Hudson's Bay Company that Moose Factory, on the southern shore of the bay, has been visited annually by a ship since 1735, with but one exception, namely in 1779, when the vessel for once failed to achieve the passage of the strait. The percentage of losses by shipwreck among these vessels employed in Hudson's Bay is far less than would have to be recorded in a like number of ships engaged in general ocean traffic. Commander Markham pointed out that until quite recently only sailing-vessels attempted to navigate Hudson's Bay, and maintained that with a properly constructed steam-vessel, there need be neither difficulty nor danger. The establishment of new routes for commerce, Commander Mark-ham concluded, is always a gain to the science of geography. In come cases new regions have to be discovered and explored. In others the physical aspects of an already known region must be more carefully studied, and many points of interest relating to the action of climates, or of winds and currents, may be ascertained. The proposed Winnipeg and Hudson's Bay Railroad is a striking instance. The objections of opponents to the route have had to be carefully examined. All former experience had to be collected, maturely considered, and passed in review. Observatories had to be established at several points, to make certain whether the historical records actually coincided with physical facts as they now exist. The route itself had to be sailed over and explored. All these various researches have been as great again to geography as to commerce. They have enriched our science with a fresh stock of information, have revised previous conceptions, and confirmed or rejected, as the case may be, the theories and views which may have been put forward. From this point of view, and from this point of view alone, can commercial or political questions receive consideration here. The study of the Hudson's Bay route involves a problem for which physical geography alone can furnish a solution.

A comprehensive anharmonic vibrational analysis of isotopic ketenes has been performed on the basis of a complete ab initio quartic force field constructed by means of second-order Mo/ller–Plesset perturbation theory (MP2) and the coupled-cluster singles and doubles (CCSD) approach, augmented for structural optimizations by a contribution for connected triple excitations [CCSD(T)]. The atomic-orbital basis sets of the study entailed C,O(10s6p/5s4p) and H(6s/4s) spaces multiply polarized in the valence region to give QZ(2d,2p) and QZ(2d1f,2p1d) sets. An iterative anharmonic vibrational refinement of a limited set of quadratic scaling parameters on 27 fundamentals of H2CCO, HDCCO, D2CCO, and H2C13CO generates a final quartic force field which reproduces the empirical νi data with an average absolute error of only 1.1 cm−1. This force field yields a complete and self-consistent set of Coriolis (ζij), vibrational anharmonic (χij), vibration–rotation interaction (αi), and quartic and sextic centrifugal distortion constants, providing a critical assessment of the assorted spectroscopic constants determined over many years and also facilitating future computations of vibrational state densities for detailed tests of unimolecular dissociation theories. The harmonic frequencies ascertained for H2CCO (in cm−1), with associated anharmonicities in parentheses, are ω1(a1)=3202.2(−129.2), ω2(a1)=2197.2(−44.4), ω3(a1)=1415.2(−25.9), ω4(a1)=1146.0(−29.7), ω5(b1)=581.9(+7.1), ω6(b1)=502.6(+26.3), ω7(b2)=3308.2(−141.3), ω8(b2)=996.0(−17.9), and ω9(b2)=433.6(+5.0). The large positive anharmonicity for the ν6(b1) C=C=O bending mode, which is principally a Coriolis effect, warrants continued investigation. Explicit first-order treatments of the strong Fermi interactions within the (ν4,2ν5,ν5+ν6,2ν6) manifold reveal resonance shifts for ν4(H2CCO, HDCCO, D2CCO) of (−12.1, −10.0, +12.2) cm−1, in order. The experimental assignments for this Fermi tetrad are confirmed to be problematic. From high-precision empirical rotational constants of six isotopomers and the theoretical anharmonic force field, the equilibrium structure of ketene is derived: re(C=O)=1.160 30(29) Å, re(C=C)=1.312 12(30) Å, re(C–H)=1.075 76(7) Å, and θe(H–C–H)=121.781(12)°. A natural bond orbital (NBO) analysis shows that the unusually large methylene angle is attributable to extensive in-plane π delocalization.