Canonical Shapes Research Articles

Atmospheric Energy Spectra in Global Kilometre-Scale Models

Eleven 40-day long integrations of five different global models with horizontal resolutions of less than 9 km are compared in terms of their global energy spectra. The method of normal-mode function decomposition is used to distinguish between balanced (Rossby wave; RW) and unbalanced (inertia-gravity wave; IGW) circulation. The simulations produce the expected canonical shape of the spectra, but their spectral slopes at mesoscales, and the zonal scale at which RW and IGW spectra intersect differ significantly. The partitioning of total wave energies into RWs an IGWs is most sensitive to the turbulence closure scheme and this partitioning is what determines the spectral crossing scale in the simulations, which differs by a factor of up to two. It implies that care must be taken when using simple spatial filtering to compare gravity wave phenomena in storm-resolving simulations, even when the model horizontal resolutions are similar. In contrast to the energy partitioning between the RWs and IGWs, changes in turbulence closure schemes do not seem to strongly affect spectral slopes, which only exhibit major differences at mesoscales. Despite their minor contribution to the global (horizontal kinetic plus potential available) energy, small scales are important for driving the global mean circulation. Our results support the conclusions of previous studies that the strength of convection is a relevant factor for explaining discrepancies in the energies at small scales. The models studied here produce the major large-scale features of tropical precipitation patterns. However, particularly at large horizontal wavenumbers, the spectra of upper tropospheric vertical velocity, which is a good indicator for the strength of deep convection, differ by factors of three or more in energy. High vertical kinetic energies at small scales are mostly found in those models that do not use any convective parameterisation.

The root-zone soil moisture spectrum in a mediterranean ecosystem

Storage of water within soil pores of the root zone introduce memory effects in the dynamics of soil moisture that are considerably longer than the integral timescale of many atmospheric processes. Thus, hydro-climatic states can be “sustained” through land-surface heat and water vapor fluxes primarily because they can “feed off” on this long-term soil moisture memory. Root-zone soil moisture memory is only but one feature characterizing the spectrum of soil moisture dynamics, which is analyzed here using a combination of long-term measurements and models. In particular, the spectrum of root-zone soil moisture content in a Mediterranean ecosystem is examined using 14-years of half-hourly measurements. A distinguishing hydro-climatic feature in such ecosystems is that sources (mainly rainfall) and sinks (mainly evapotranspiration) of soil moisture are roughly out of phase with each other. For over 4 decades of time scales and 7 decades of energy, the canonical shape of the measured soil moisture spectrum is shown to be approximately Lorentzian determined by the soil moisture variance and its memory but with two exceptions: the occurrences of a peak at diurnal-to-daily time scales and a weaker peak at near annual time scales. Model calculations and spectral analysis demonstrate that diurnal and seasonal variations in hydroclimate forcing responsible for variability in evapotranspiration had minor impact on the normalized shape of the soil moisture spectrum. However, their impact was captured by adjustments in the temporal variance. These findings indicate that precipitation and not evapotranspiration variability dominates the multi-scaling properties of soil moisture variability consistent with prior climate model simulations. Furthermore, the soil moisture memory inferred by the annual peak of soil moisture (340 d) is consistent with climate model simulations, while the memory evaluated from the loss function of a linearized mass balance approach leads to a smaller value (50 d), highlighting the effect of weak non-stationarity on soil moisture variability.

Methodology for predicting the washability of apatite ores (Kirovsky mine, Kola Peninsula)

A statistical approach has been proposed that allows strictly defining the structure of a rock (ore), isolating fields of various structures in barycentric diagrams, and comparing them with the processing results. An original method is proposed for predicting the washability defined as the separation of apatite grains from polymineral aggregations at the crushing and flotation stages. It develops and formalizes the current approach that combines the mineral composition of ores, their structures and textures into a multifactor semiquantitative model. The method is based on the calculation of the probabilities (frequencies) of all types of intergranular contacts recorded in a symmetric matrix under a microscope in petrographic thin sections. Its canonical diagonal shape allows identifying the rock (ore) structure type. The algebraic theory of quadratic forms is used to demonstrate that the structure identified using this method corresponds to one of the types of n-dimensional nondegenerate quadratic surfaces, where n is the number of minerals in the rock (ore). The structure is invariant for a certain fluctuation in the probabilities of intergranular contacts. The calculated probabilities uniquely identify the imaging point in the corresponding barycentric diagram. The Hardy–Weinberg boundary is important as it corresponds to the ideal uniform mixing of minerals and the balance of various intergranular contacts for any modal composition of rocks (ores). It allows distinguishing fields of different structures in barycentric diagrams. The method proposed offers a means to identify ores with different washability characteristics at early exploration stages.

Explicit short-wave representations and Ray Tracing method for reflections from curved surfaces in room acoustics

A short-wave asymptotic method is proposed to solve the problem of multiple reflections of sound rays from curved surfaces, as well as from a system of curved surfaces. At the beginning, we give a brief survey of the proposed method for single reflection. Then this general approach is demonstrated in the case of spherical and cylindrical canonical surfaces. To provide a more physical impression of a rather mathematical development, we give a comparison of the analytical asymptotic formulas with the results obtained by the Ray Tracing method (RTM), in the case of canonical geometries. Further, there is given a brief survey of analogous method in the case of double reflection, for surfaces of a general geometry, which is clarified again for double reflection from the surfaces of canonical shapes. At last, we give some general conclusions which may be important in practical aspect.

Kinesin-5 and kinesin-14 are partially antagonistic in spindle assembly in the holocentric silkworm B. mori cells.

We previously showed that the silkworm holocentric spindles are square-shaped, compared to the canonical oval shape of human monocentric spindles (Vanpoperinghe et al. 2021). Further, while kinesin-5 depletion resulted in monopolar spindles in both cells, kinesin-14 depletion affected only the silkworm cells, resulting in mal-shaped spindles (Vanpoperinghe et al. 2021). We now extend our study to quantify the effect of kinesin-5 and kinesin-14 on spindle assembly dynamics and chromosome segregation in holocentric silkworm BmN4 cells. We find that mal-shaped spindle and prolonged mitosis duration are highly correlated with chromosome segregation error, leading to aneuploidy and cell death in BmN4 cells. Further, double RNAi-mediated depletion of kinesin-5 and kinesin-14 partially rescue the monopolar spindle and mal-shaped spindle phenotypes in kinesin-5 and kinesin 14-depleted cells, respectively.

A Representation Separation Perspective to Correspondence-Free Unsupervised 3-D Point Cloud Registration

3D point cloud registration in remote sensing field has been greatly advanced by deep learning based methods, where the rigid transformation is either directly regressed from the two point clouds (correspondences-free approaches) or computed from the learned correspondences (correspondences-based approaches). Existing correspondences-free methods generally learn the holistic representation of the entire point cloud, which is fragile for partial and noisy point clouds. In this paper, we propose a correspondences-free unsupervised point cloud registration (UPCR) method from the representation separation perspective. First, we model the input point cloud as a combination of pose-invariant representation and pose-related representation. Second, the pose-related representation is used to learn the relative pose wrt a "latent canonical shape" for the source and target point clouds respectively. Third, the rigid transformation is obtained from the above two learned relative poses. Our method not only filters out the disturbance in pose-invariant representation but also is robust to partial-to-partial point clouds or noise. Experiments on benchmark datasets demonstrate that our unsupervised method achieves comparable if not better performance than state-of-the-art supervised registration methods.

A viral RNA hijacks host machinery using dynamic conformational changes of a tRNA-like structure

A tricky mimicry RNA viruses use dynamic, multifunctional folded elements to hijack host cellular machinery. Bonilla et al . used cryo–electron microscopy (cryo-EM) to explore an RNA element from Brome mosaic virus that tricks host cell tyrosine transfer RNA synthetase (TyrRS) into adding a tyrosine to the viral genome’s 3′ end. Visualizing this RNA both in isolation and bound to a cellular TyrRS revealed a bound structure unlike the canonical transfer RNA L-like shape and conformational rearrangements in the RNA upon binding to the TyrRS, which suggests a multistep process of enzyme recognition. This study highlights the power of cryo-EM to illustrate dynamic processes involving small structured RNAs and RNA-protein complexes. —DJ

As-rigid-as-possible volume tracking for time-varying surfaces

Surfaces evolving through time are hard to analyze without prior knowledge of the represented deforming shape. Topological noise introduced by inaccuracies during surface capture and reconstruction renders the estimation of time-consistent correspondence an ill-posed problem. It has previously been shown that this problem may be mitigated by tracking the volume within the surface rather than the surface itself. Assuming that the captured phenomenon does not involve sudden appearance or disappearance of volume, it is possible to establish a bijective correspondence of volume elements, which in turn may be used for various purposes, such as extracting a canonical shape and guiding the computation of surface correspondence.In this paper, we discuss an improved volume tracking methodology that provides better results by modifying the energy formulation and by incorporating a notion of volume element affinity, combined with an improved optimization strategy. We also discuss two metrics that, when combined, quantify the quality of the tracking results.

Design of Broadband Compact Canonical Triple-Sleeve Antenna Operating in UHF Band

In this paper, a novel compact broadband antenna at UHF frequencies is presented with canonical shapes. Hemispherical, conical and cylindrical shapes have all been considered for antenna configuration. The designed antenna provides an instantaneous frequency range from 370 to 5,000 MHz with omnidirectional characteristics. The antenna was simulated in CST Microwave Studio, fabricated and evaluated; the results are presented. The simulated and measurement results are in good agreement. The antenna has voltage standing wave ratio (VSWR) ≤ 1.9:1 in 400–570 MHz, 2,530–3,740 MHz and 4,180–4,620 MHz; it has VSWR ≤ 3:1 over the operating frequency range 370–5,000 MHz and the measured gain varies from -0.6 to 4.5 dBi over the frequency band. The concept of canonical-shaped antenna elements and the incorporation of triple sleeves resulted in a reduction of the length of the antenna by 62% compared to the length of a half-wave dipole antenna designed at the lowest frequency. The antenna can be used for trans-receiving applications in wireless communication.

Interaction of punches of canonical shapes with an elastic base with two bedding coefficients

Interaction of punches of canonical shapes with an elastic base with two bedding coefficients

Fast method for solving integral equations of electromagnetic wave scattering from perfect conductor three-dimensional objects using Fourier series

ABSTRACT In this paper, an easy method is proposed to reduce the computational complexity of matrix-vector multiplication that is required in solving integral equations using method of moments. This method approximates the Green’s function using a Fourier series. It has the advantage that its formulation separates the observation point from the source point effortlessly and regardless of the Green’s function. Since the fast multipole method uses this idea, the two methods are discussed and compared theoretically and numerically by solving the electromagnetic wave scattering from perfect conductor of three-dimensional basic canonical shape (sphere). The results showed that the proposed method is accurate, and for large number of unknowns in the problem, it has a computational complexity less than the method of moments and over the conventional fast multipole method. Hence, the generality and simplicity of this method compare with the conventional fast multipole method and the efficiency compare with the method of moments, which will be achieved.

Modeling of Thermal Conductivity in a Medium with Phase Transition with a Moving Boundary of Phase Change

This work is devoted to the theoretical study of the effect of the phase interface motion on thermal conductivity in a liquid-solid nonlinear medium with a phase transition. The problem under consideration deals with the Stefan problems. Its most significant feature is the jump in the phase properties at separation of their moving boundaries. The objective was achieved by solving the following tasks: the construction of the process mathematical model based on its cell representation and with the use of the Markov chain theory mathematical apparatus, performing numerical experiments with the developed model, demonstrating its operability and the possibility to achieve the set goal. The most significant scientific results were as follows. First was an algorithm for the construction of a cell mathematical model of nonlinear thermal conductivity in a phase transitions medium with a moving phase interface for domains of a canonical shape (plane wall, cylinder, ball). Second, the results of the numerical experiments, showing that the jump of properties affected greatly the kinetics of the process. The significance of the results obtained consisted in the development of a simple but informative mathematical model of the media heat treatment kinetics with phase transformations, available for a direct use in the engineering practice. The proposed algorithm for constructing the model can be effectively used in prediction the open water pipes freezing in cold regions, in modeling the heat treatment of metals, in choosing the freezing modes of food products for a long-term storage, and other thermo-physical processes.

Effect of Non-canonical Spatial Symmetry on Subitizing.

Subitizing refers to ability of people to accurately and effortlessly enumerate a small number of items, with a capacity around four elements. Previous research showed that “canonical” organizations, such as familiar layouts on a dice, can readily improve subitizing performance of people. However, almost all canonical shapes found in the world are also highly symmetrical; therefore, it is unclear whether previously reported facilitative effect of canonical organization is really due to canonicality, or simply driven by spatial symmetry. Here, we investigated the possible effect of symmetry on subitizing by using symmetrical, yet non-canonical, shape structures. These symmetrical layouts were compared with highly controlled random patterns (Experiment 1), as well as fully random and canonical patterns (Experiment 2). Our results showed that symmetry facilitates subitizing performance, but only at set size of 6, suggesting that the effect is insufficient to improve performance of people in the lower or upper range. This was also true, although weaker, in reaction time (RT), error distance measures, and Weber Fractions. On the other hand, canonical layouts produced faster and more accurate subitizing performances across multiple set sizes. We conclude that, although previous findings mixed symmetry in their canonical shapes, their findings on shape canonicality cannot be explained by symmetry alone. We also propose that our symmetrical and canonical results are best explained by the “groupitizing” and pattern recognition accounts, respectively.

Simplified Evaluation of Ground Motion Amplification in the Vicinity of a Topographic Feature

ABSTRACT A two-parameter expression for the quantification of topographic effects in ground response analysis at sites located in the vicinity of a topographic feature is presented. The expression is derived from parametric analysis of convex and concave canonical shapes after identifying that the diffracted field in these geometries remains relatively stable in the low dimensionless frequency regime. The proposed expression is used in the estimation of topographic effects at two sites located in realistic topographic scenarios over a given period range. To show the quality of the approximate formula results are compared with numerical simulation values.

Voluntary attention improves performance similarly around the visual field.

Performance as a function of polar angle at isoeccentric locations across the visual field is known as a performance field (PF) and is characterized by two asymmetries: the HVA (horizontal-vertical anisotropy) and VMA (vertical meridian asymmetry). Exogenous (involuntary) spatial attention does not affect the shape of the PF, improving performance similarly across polar angle. Here we investigated whether endogenous (voluntary) spatial attention, a flexible mechanism, can attenuate these perceptual asymmetries. Twenty participants performed an orientation discrimination task while their endogenous attention was either directed to the target location or distributed across all possible locations. The effects of attention were assessed either using the same stimulus contrast across locations or equating difficulty across locations using individually titrated contrast thresholds. In both experiments, endogenous attention similarly improved performance at all locations, maintaining the canonical PF shape. Thus, despite its voluntary nature, like exogenous attention, endogenous attention cannot alleviate perceptual asymmetries at isoeccentric locations.

Depth Privileged Object Detection in Indoor Scenes via Deformation Hallucination

RGB-D object detection has achieved significant advance, because depth provides complementary geometric information to RGB images. Considering depth images are unavailable in some scenarios, we focus on depth privileged object detection in indoor scenes, where the depth images are only available in the training phase. Under this setting, one prevalent research line is modality hallucination, in which depth image and depth feature are the common choices for hallucinating. In contrast, we choose to hallucinate depth deformation, which is explicit geometric information and efficient to hallucinate. Specifically, we employ the deformable convolution layer with augmented offsets as our deformation module and regard the offsets as geometric deformation, because the offsets enable flexibly sampling over the object and transforming to a canonical shape for ease of detection. In addition, we design a quality-based mechanism to avoid negative transfer of depth deformation. Experimental results and analyses on NYUDv2 and SUN RGB-D demonstrate the effectiveness of our method against the state-of-the-art methods for depth privileged object detection.

23154 Electrical stimulation of hippocampus and amygdala produces multiple distinct responses in human ventral temporal cortex

ABSTRACT IMPACT: This study characterizes interactions between human limbic circuitry and ventral temporal cortex using single pulse electrical stimulation, which may inform emerging stimulation therapies for epilepsy. OBJECTIVES/GOALS: The goal of electrical brain stimulation treatment is to modulate brain network function. However, stimulation inputs to different brain sites alter the network in a variety of ways. This study examines that variability by characterizing responses in a target region while stimulating multiple other brain sites. METHODS/STUDY POPULATION: We measured voltages in intracranial EEG in 6 patients who had electrodes implanted for epilepsy monitoring. We stimulated pairs of electrodes at multiple sites in the brain with a single pulse every 5 to 7 s and measured the resulting corticocortical evoked potential (CCEP) responses in the ventral temporal cortex (VTC). Using a novel clustering method, we uncovered sets of distinct canonical response shapes from the 20 to 500 ms post-stimulation period. This allowed us to group stimulation sites that evoked similar responses. We then related each group to high frequency, broadband, changes in spectral power as a reflection of local neuronal activity. RESULTS/ANTICIPATED RESULTS: We found that the VTC receives strong inputs specifically from the amygdala and hippocampus, both in terms of amplitude and broadband spectral power change. However, inputs from the hippocampus produced a different canonical shape than those from the amygdala. We also observed that VTC responses to inputs from the insula clustered in shape with those from the amygdala. These clustering patterns were consistent across subjects, although the actual shapes of the clusters showed variability. We further observed that some shapes were more associated with increases in overall neuronal activity than others, as reflected by broadband spectral power change. DISCUSSION/SIGNIFICANCE OF FINDINGS: Stimulation of connected sites may drive excitability at the target region in ways that are described by sets of full-time-course responses. By capturing their shapes, we can begin to decipher canonical input types at the circuit level. This approach might identify how stimulation inputs can be tailored to therapy while mitigating adverse effects.

Cross-linguistic comparison of utterance shapes in Korean- and English-learning children: An ambient language effect

This study compared vocal development in Korean- and English-learning infants and examined ambient-language effects focusing on predominant utterance shapes. Vocalization samples were obtained from 14 Korean-learning children and 14 English-learning children, who ranged in age from 9 to 21 months, in monolingual environments using day-long audio recordings. The analyzers, who were blind to participants’ demographic information, identified utterance shapes to determine functional vocal repertoires through naturalistic listening simulating the caregiver’s natural mode of listening. The results showed no cross-linguistic differences in the amount of vocal output or the proportion of canonical syllables. However, the infants from the two language backgrounds showed differences regarding the predominant canonical utterance shapes. The percentage of VCV utterances in Korean-learning children was higher than in English-learning children while CV syllables predominated in the English-learning children. We speculate that the difference between the predominant utterance shapes of Korean- and English-learning children could be associated with differences in early lexical items typically acquired in the two language groups.

METHOD OF «MICROPROCESSES» IN MODELING THE PROCESSES OF THERMAL CONDUCTIVITY AND DIFFUSION IN BODIES OF CANONICAL SHAPE. GENERALIZED BOUNDARY CONDITIONS OF THE THIRD KIND

Most of the materials undergoing processing in the production processes of chemical technology, from the point of view of the principles of geometry, can be reduced to traditional bodies of canonical shape: a plate, a cylinder, a ball. In the processes of heat treatment of solid materials (heat-moisture treatment, drying, firing), the transfer potentials (temperature, mass content) change significantly over the time of the process. To solve boundary value problems of heat and mass (moisture) conductivity in such cases, the zonal method and the microprocess method were previously proposed. The possibilities of the microprocesses method applied to modeling boundary value problems of heat and mass transfer for bodies of canonical shape under boundary conditions of the first kind (Dirichlet conditions) were shown in the previous works of the authors. This paper presents an illustration of the application of the microprocess method for solving boundary value problems of heat and moisture conductivity under more general boundary conditions, conditions of the third kind (Rie-mann-Newton). The great universality of these conditions lies in the fact that, depending on the values of the Biot number (Bi), they transform into a condition of the first kind (Bi tends to zero) or the second (Bi tends to infinity). It is shown that the search for solutions in the region of small values of Fourier numbers (Fo <0.1) is promising for modeling the processes of heat and mass transfer in systems with a solid phase based on the method of micro-processes. Solutions of the corresponding boundary value problems are given and examples of the results of their numerical implementation are shown.

Dielectric Resonator Antenna Geometry-Dependent Performance Tradeoffs

A flexible shape generation technique (Surface Contour Shape Generation) is combined with multiobjective evolutionary optimization algorithms in order to synthesize geometrically-diverse dielectric resonator antennas and explore the impact geometry has on relevant performance metrics. It is shown that noncanonical shapes can improve gain and bandwidth when compared to conventional dielectric resonator antenna geometries. Previously described free-form techniques (such as the superformula) have demonstrated improved performance over canonical shapes, but are difficult to integrate with inverse-design. In contrast, the proposed shape generation technique is coupled with multiobjective optimization in order to illustrate the solution space tradeoffs between the various design goals. This technical approach is compatible with various feed designs, antenna performance parameters, and 3D printing techniques.