Superimposed polygonal approximation analysis comparing 2D photography and 3D scanned images of bite marks on human skin

Background Preservation of bite marks evidence has always been a major problem in forensic odontology due to progressive loss of details as time passes. The use of 2D photographs has been widely used to document forensic evidence and preserving bite marks; however, there are limitations to this method. This study aims to measure the accuracy of the 3D scanned image in comparison to 2D photograph registration of experimental bite marks. Thirty volunteers performed self-exertions of a bite mark on the respective forearm of subjects. A 2D photograph and 3D scanned image was immediately registered following bite mark exercise using a conventional camera and Afinia EinScan-Pro 2X PLUS Handheld 3D Scanner, respectively. The outlines of the bite mark were transformed into a polygonal shape. Next, the polygonal approximation analysis was performed by an arbitrary superimposition method. The difference between surface areas of both images was calculated (2D photographs ̶ 3D scanned images). Results A paired t test was used to measure significance with α = 0.05. The mean surface area of 2D photographs and 3D scanned images is 31.535 cm2 and 31.822 cm2, respectively. No statistical difference was found between both mean surface areas (p > 0.05). The mean error (ME) is 0.287 ± 3.424 cm2 and the mean absolute error (MAE) is 1.733 ± 1.149 cm2. Conclusion Bite marks registered with the 3D scanned image are comparable to the standard 2D photograph for bite mark evaluations. The use of a 3D scan may be adopted as a standard operating procedure in the forensic application, especially for evidence preservation.

(Re) pensar la competencia motriz ((Re) think motor competence)

Este artículo pretende caracterizar la competencia motriz como un constructo teórico, teniendo en cuenta el conocimiento científico desde una perspectiva praxiológica. Para ello, trataremos de determinar cuáles serían las dimensiones que la configuran y sus características. Considerando que nuestro estudio se pretende vincular a la Educación Física Escolar, se ha tomado la conducta motriz como su referente, entendida como la organización significativa del comportamiento motor. Se ha utilizado una estrategia de investigación cualitativa, que combinó las técnicas del análisis documental con grupo de expertos. Para ello, se hizo un análisis de aproximación semántica del término y de sus antecedentes, empleando una metodología de búsqueda documental y análisis de contenido. Se concluye que las dimensiones que nos permiten caracterizar la competencia motriz como una competencia específica son: la biológica, la cognitiva, la afectiva, la interactiva y la de ejecución motriz o práxica. Desde esta perspectiva, la competencia motriz se manifiesta por medio de la conducta motriz en las situaciones motrices de la Educación Física Escolar. Abstract. This work tries to characterize the motor competence as a theoretical construct, taking into account the scientific knowledge from a praxiological perspective. For this, we will try to determine what would be the dimensions that configure it and its characteristics. Considering that our study is linked to School Physical Education, motor behavior has been taken as its referent, understood as the significant organization of motor behavior. A qualitative research strategy was used, which combined the techniques of documentary analysis with a group of experts. For this, a semantic approximation analysis of the term and its background was made, using a documentary search methodology and content analysis. It is concluded that the dimensions that allow us to characterize motor competence as a specific competence are: biological, cognitive, affective, interactive, and motor or praxic execution. From this perspective, motor competence is manifested through motor behavior in motor situations of School Physical Education.

Electromagnetic Steklov eigenvalues: approximation analysis

We continue the work of [Camano, Lackner, Monk, SIAM J.\ Math.\ Anal., Vol.\ 49, No.\ 6, pp.\ 4376-4401 (2017)] on electromagnetic Steklov eigenvalues. The authors recognized that in general the eigenvalues due not correspond to the spectrum of a compact operator and hence proposed a modified eigenvalue problem with the desired properties. The present article considers the original and the modified electromagnetic Steklov eigenvalue problem. We cast the problems as eigenvalue problem for a holomorphic operator function $A(\cdot)$. We construct a ``test function operator function'' $T(\cdot)$ so that $A(\lambda)$ is weakly $T(\lambda)$-coercive for all suitable $\lambda$, i.e.\ $T(\lambda)^*A(\lambda)$ is a compact perturbation of a coercive operator. The construction of $T(\cdot)$ relies on a suitable decomposition of the function space into subspaces and an apt sign change on each subspace. For the approximation analysis, we apply the framework of T-compatible Galerkin approximations. For the modified problem, we prove that convenient commuting projection operators imply T-compatibility and hence convergence. For the original problem, we require the projection operators to satisfy an additional commutator property involving the tangential trace. The existence and construction of such projection operators remain open questions.

Tropical Precipitation Evolution in a Buoyancy-Budget Framework

Observations have shown that tropical convection is influenced by fluctuations in temperature and moisture in the lower free-troposphere (LFT, 600–850 hPa), as well as moist enthalpy (ME) fluctuations beneath the 850 hPa level, referred to as the deep boundary layer (DBL, 850–1000 hPa). A framework is developed that consolidates these three quantities within the context of the buoyancy of an entraining plume. A “plume buoyancy equation” is derived based on a relaxed version of the weak-temperature gradient (WTG) approximation. Analysis of this equation using quantities derived from the Dynamics of the Madden-Julian Oscillation (DYNAMO) sounding array data reveals that processes occurring within the DBL and the LFT contribute nearly equally to the evolution of plume buoyancy, indicating that processes that occur in both layers are critical to the evolution of tropical convection. Adiabatic motions play an important role in the evolution of buoyancy both at the daily and longer timescales and are comparable in magnitude to horizontal moisture advection and vertical moist static energy advection by convection. The plume buoyancy equation may explain convective coupling at short timescales in both temperature and moisture fluctuations and can be used to complement the commonly-used moist static energy budget, which emphasizes the slower evolution of the convective envelope in tropical motion systems.

Perturbation Theory Near Degenerate Exceptional Points

In an overall framework of quantum mechanics of unitary systems a rather sophisticated new version of perturbation theory is developed and described. The motivation of such an extension of the list of the currently available perturbation-approximation recipes was four-fold: (1) its need results from the quick growth of interest in quantum systems exhibiting parity-time symmetry (PT-symmetry) and its generalizations; (2) in the context of physics, the necessity of a thorough update of perturbation theory became clear immediately after the identification of a class of quantum phase transitions with the non-Hermitian spectral degeneracies at the Kato’s exceptional points (EP); (3) in the dedicated literature, the EPs are only being studied in the special scenarios characterized by the spectral geometric multiplicity L equal to one; (4) apparently, one of the decisive reasons may be seen in the complicated nature of mathematics behind the L≥2 constructions. In our present paper we show how to overcome the latter, purely technical obstacle. The temporarily forgotten class of the L>1 models is shown accessible to a feasible perturbation-approximation analysis. In particular, an emergence of a counterintuitive connection between the value of L, the structure of the matrix elements of perturbations, and the possible loss of the stability and unitarity of the processes of the unfolding of the singularities is given a detailed explanation.