OBJECTIVE: The current method of preimplantation genetic testing for aneuploidy (PGT-A) involves invasive trophectoderm (TE) biopsy. Although PGT-A has improved the success rate per embryo transfer, it has notable limitations. These include the cost of sequencing, mosaicism, the skill required to biopsy TE cells, and the fact that only a select number of blastocysts (BLs) can be tested. Embryologists rely on morphological assessment and clinical information to select BLs for PGT-A. The development of noninvasive methods of embryo screening, as an alternative to PGT-A, is essential. We propose an embryo selection method that leverages the power of deep learning classification methods trained on spatial and temporal information stored in time-lapse images (TLM) that capture embryo development along with clinical parameters; this method can be used to select embryos for PGT-A and to predict embryo ploidy (euploid vs. aneuploid) without a biopsy.DESIGN: In our study, we used a retrospective dataset consisting of 10,872 embryos of known ploidy status (euploid or aneuploid) to train and validate several deep learning models.MATERIALS AND METHODS: We developed deep learning models for embryo image analysis based on pre-trained ResNet18. The models utilized images of human embryos captured using time-lapse microscopy (Embryo-Scope TM ) at 110 hours post-ICSI and known PGT-A results (aneuploid n ¼ 6,443; euploid n ¼ 4,429) as ground truth labels. The developed models use several clinical features, including maternal age, morphokinetics, BL grade, and BL score. Using an 80/20 training-validation split of the data, performances were measured by validation accuracy and the AUC. Class activation mapping (CAM) was employed to identify which areas within embryo images were used to predict ploidy.RESULTS: Several models were trained and validated, each with varying features.

A harmonically-driven, incompressible, electrically conducting, and viscous liquid metal magnetohydrodynamic flow through a thin walled duct of rectangular cross section interacting with a uniform magnetic field traverse to its motion direction is numerically investigated. Chebyshev spectral collocation method is used to solve the Navier-Stokes equation under the inductionless approximation for the magnetic field in the gradient formulation for the electric field. Flow is considered fully developed in the direction perpendicular to the applied magnetic field and laminar in regime. Validation of numerical calculations respect to analytical calculations is established. Flow structure and key magnetohydrodynamic features regarding eventual alternating power generation application in a rectangular channel liquid metal magnetohydrodynamic generator setup are numerically inquired. Influence of pertinent parameters such as Hartmann number, oscillatory interaction parameter and wall conductance ratio on magnetohydrodynamic flow characteristics is illustrated. Particularly, it is found that in the side layer and its vicinity the emerging flow structures/patterns depend mainly on the Hartmann number and oscillatory interaction parameter ratio, while the situation for the Hartmann layer and its vicinity is less eventful. A similar feature has been discussed in the literature for the steady liquid metal flow case and served as rationale for developing the composite core-side-layer approximation to study the magnetohydrodynamics of liquid metal flows usable in direct power generation. In this study that approximation is not considered and the analysis is performed on liquid metal oscillatory (i., e., unsteady) flows usable in alternating power generation. Conversely, in terms of prospective practical applicability the formulation developed and tested with these calculations admits the implementation of a load resistance and walls conductivity optimization. That means that besides representing a numerical study on the magnetohydrodynamics of the oscillatory flow under consideration, absent in the literature for the parametric ranges reported, the formulation presently implemented can also be applicable to study the performance of an alternating liquid metal magnetohydrodynamic generator in the rectangular channel configuration.

A harmonically driven oscillatory fully developed laminar flow through a rectangular cross-sectioned duct is analytically and experimentally studied. Experimental data is gathered at low cost with a relatively easy to implement, non-commercial, do-it-yourself (DIY) particle image velocimetry (PIV) system, which is proposed here as a flexible pedagogic resource for use in physics/engineering fluid mechanics undergraduate or graduate level education. As a DIY system, its components can be generic and/or open source based, making it useful in developing countries as well. An analytical model was developed, solved, and compared to the experimental data while the key features of the oscillatory flow were recognised and reciprocally represented by theory and experiments. This validated the proposed system as a low-cost alternative to the commercially available systems and it also confirmed it as a viable pedagogical resource. Consequently, the activities described could be straightforwardly implemented into undergraduate/graduate fluid mechanics pedagogical contexts, such as lecture aids, course projects, and laboratory practices. The proposed DIY-PIV system constitutes a teaching with technology pedagogical resource on fluid mechanics physics/engineering education that is also able to function as a limited/auxiliary or even state of the art research tool, according to the budget and the objectives.

Tactic and strategic management and policing of atmospheric pollution in México, specifically by particulate material (PM) from mobile sources (internal combustion powered vehicles), critically requires state-of-the-science technologies due to the problem's complexity including its public health dimension. The authors consider that proper decision making on the problem would benefit from permanent revision on currently employed PM monitoring and measurement systems and also the effort to improve them. These later currently offer information on O(10^0) ultraviolet-visible-infrared (UV-VIS-IR) spectral bands at O(10^0) spatial resolutions and O(10^1) in [min^-1] temporal resolutions. In contrast, they propose the novel use of acousto-optic tunable filter (AOTF) spectrometry to study PM in atmospheric suspension, capable of offering information on O(10^2) UV, VIS, or IR spectral bands at similar or better spatial and temporal resolutions. The potential of AOTF spectrometry towards PM assessment is clear and the objective is to explore its usefulness.

Durante los años de gestación de la Teoría General de la Relatividad (TGR) y de la subsiguiente cosmología relativista, Albert Einstein esperaba que su teoría de gravitación satisficiera las ideas de Mach sobre la inercia. Ello ocurría a causa de postular un origen material para la inercia. Se sabe que Einstein encontró dificultades importantes para reconciliar su TGR con el Principio de Mach. En este artículo se discuten los alcances de la teoría alternativa de gravitación clásica de J. Barbour y B. Bertotti. Ésta pretende incorporar en forma consistente el Principio de Mach en el contexto de la dinámica clásica. Su relevancia conceptual y heurística es discutida.