Hippocampal Representations for Deep Learning on Alzheimer’s Disease

Deep learning offers a powerful approach for analyzing hippocampal changes in Alzheimer's disease (AD) without relying on handcrafted features. Nevertheless, an input format needs to be selected to pass the image information to the neural network, which has wide ramifications for the analysis, but has not been evaluated yet. We compare five hippocampal representations (and their respective tailored network architectures) that span from raw images to geometric representations like meshes and point clouds. We performed a thorough evaluation for the prediction of AD diagnosis and time-to-dementia prediction with experiments on an independent test dataset. Our results show that choosing an appropriate representation of the hippocampus for predicting Alzheimer's disease with deep learning is crucial, since it impacts performance and ease of interpretation.

Digital transformation in topographic databases

The increasingly widespread implementation of databases with geographical component, as well as the impregnation of geolocation culture, is driving a transformation in the storage, management and exploitation of geospatial information. Real-world elements go from being modeled as mere geometric representations, with just cartographic purposes, to be features with their own entity. Unique identifiers and lifecycle management are assigned to these features, allowing interactions between feature instances from different databases, that is, facilitating digital transformation and, therefore, increasing exponentially the exploitation possibilities.In this regard, the National Geographic Institute of Spain (IGN, by its Spanish acronym) have implemented several processes in its National Topographic Database, such as the connection with the cadastral information, in order to take advantage of its updates and give feedback to improve cadastral data; or the link with the information, in addresses form, provided from different public administration, that is processed to geolocate features in the topographic database. Likewise, work is being done in order to implement new processes that allow linking with other data sets.These processes, in addition to reusing information produced by different public administrations, constitute an advance towards the objective of geospatial information databases continuous updating.

GEOMETRIC REPRESENTATIONS OF EQUILIBRIUM CURVES OF A COMPRESSED STIFFENED PLATE

The work is aimed at studying the solutions of the stability problem (subcritical and postcritical equilibrium) of an infinitely wide regular compressed reinforced plate, using a selected T-shaped fragment that is equally stable with others. The authors have given a classification of possible analytical solutions for these plates. The results of the work are presented in the form of variants of spatial bifurcation diagrams, values of critical loads, as well as coordinates of singular points for different cases of solutions.

Contribuições das pesquisas em ensino de ciências e matemática atinentes à produção escrita

Resumo: Neste artigo apresentamos resultados de uma pesquisa de caráter bibliográfico, com a intenção de conhecer as investigações atinentes à produção escrita (PE) presentes em trabalhos acadêmicos da área de Ensino de Ciências e Matemática. Com o intuito de identificar em que contexto de investigação a produção escrita foi empregada e como os autores desses trabalhos compreendem o termo produção escrita, utilizamos os procedimentos metodológicos da Análise de Conteúdo para selecionar e analisar 65 Dissertações e 17 Teses. Como resultados, evidenciamos que as pesquisas em Ensino de Ciências e Matemática utilizaram a produção escrita como instrumento de aprendizagem ou como instrumento formativo, uma vez que objetivaram investigar os conhecimentos mobilizados pelos sujeitos que realizaram a PE ou estiveram relacionadas à aprendizagem docente dos sujeitos que analisaram ou realizaram a PE. Constatamos, também, que a produção escrita apresentada nesses trabalhos acadêmicos consistiu em registros escritos, desenhos, representações geométricas, colagens e resoluções matemáticas.Palavras-chave: Produção escrita; Pesquisas acadêmicas; Ensino de Ciências e Matemática. Contributions of research in science and mathematics teaching related to writtten productionAbstract: In this article, we present results of a bibliographic research with the intention of knowing the investigations related to the written production in academic research in the area of Science and Mathematics Teaching. In order to identify in which research context was employed the written production and how the authors of these works understood written production, we used the methodological procedures of Content Analysis to select and analyze 65 Dissertations and 17 Theses. As a result, we found that research in Science and Mathematics Teaching used written production as a learning tool or as a training tool, since they investigated the knowledge mobilized by the subjects who carried out the written production, or were related to the teaching learning of the subjects who analyzed or carried out the written production. We also verified that the written production presented in these academic works consisted of written records, drawings, geometric representations, collages and mathematical resolutions.Keywords: Written production; Academic research; Science and Mathematics Teaching.

CONSTRUCTION TASKS AS A MEANS OF FORMING METHODS OF THINKING ACTIVITY

The article considers the essence of the concept of mental activity, analyzes the problem of human thinking, shows the role of building tasks in the formation of mental activity of secondary school students. The main feature of the construction tasks is that they develop search skills for solving problems, introduce them to feasible independent research, contribute to the development of geometric representations and the processing of knowledge, skills, thereby strengthening not only the applied orientation of geometry teaching, but also the polytechnic one. Construction tasks do not allow a formal approach to them, they create a problematic situation that needs to be solved, as a result of which the level of mental activity increases. Pedagogical experience shows that due to lack of time, teachers do not see the need to return to the construction tasks, and school textbooks pay little attention to the construction tasks, so elective classes and elective seminars on this topic are necessary. The optimal number of classes should be 10 hours, especially for grades 7-9. The authors tested their own methodology (ascertaining, forming and control stages) among students of the 7th grade of one of the schools in Uralsk.

Geometry of Multiprimary Display Colors I: Gamut and Color Control

<div>Displays that render colors using combinations of more than three lights are referred to as multiprimary displays. For multiprimary displays, the gamut, i.e., the range of colors that can be rendered using additive combinations of an arbitrary number of light sources (primaries) with modulated intensities, is known to be a zonotope, which is a specific type of convex polytope. Under the specific three-dimensional setting relevant for color representation and the constraint of physically meaningful nonnegative primaries, we develop a complete, cohesive, and directly usable mathematical characterization of the geometry of the multiprimary gamut zonotope that immediately identifies the surface facets, edges, and vertices and provides a parallelepiped tiling of the gamut. We relate the parallelepiped tilings of the gamut, that arise naturally in our characterization, to the flexibility in color control afforded by displays with more than four primaries, a relation that is further analyzed and completed in a Part II companion paper. We demonstrate several applications of the geometric representations we develop and highlight how the paper advances theory required for multiprimary display modeling, design, and color management and provides an integrated view of past work on on these topics. Additionally, we highlight how our work on gamut representations connects with and furthers the study of three-dimensional zonotopes in geometry.</div>

Geometry of Multiprimary Display Colors I: Gamut and Color Control

<div>Displays that render colors using combinations of more than three lights are referred to as multiprimary displays. For multiprimary displays, the gamut, i.e., the range of colors that can be rendered using additive combinations of an arbitrary number of light sources (primaries) with modulated intensities, is known to be a zonotope, which is a specific type of convex polytope. Under the specific three-dimensional setting relevant for color representation and the constraint of physically meaningful nonnegative primaries, we develop a complete, cohesive, and directly usable mathematical characterization of the geometry of the multiprimary gamut zonotope that immediately identifies the surface facets, edges, and vertices and provides a parallelepiped tiling of the gamut. We relate the parallelepiped tilings of the gamut, that arise naturally in our characterization, to the flexibility in color control afforded by displays with more than four primaries, a relation that is further analyzed and completed in a Part II companion paper. We demonstrate several applications of the geometric representations we develop and highlight how the paper advances theory required for multiprimary display modeling, design, and color management and provides an integrated view of past work on on these topics. Additionally, we highlight how our work on gamut representations connects with and furthers the study of three-dimensional zonotopes in geometry.</div>

Nubian Rock Art

Nubian rock art consists of handmade works on rock surfaces that differ significantly from the official images and texts of pharaonic Egypt. The oldest examples of such art are dated to the late Palaeolithic age and the Epipaleolithic Period. These are geometric representations as well as naturalistic depictions of bovids (wild cattle or aurochs), birds, hippopotamuses, gazelles, fish, hartebeest and stylized human figures, dated as far back as 15,000 bce. Similar motifs can be found both in the Nile Valley and in the adjacent desert areas of Upper Egypt and Lower Nubia, indirectly cited as proof of the existence of common cultural traditions in these regions and the notable mobility of contemporary hunter groups. Although Upper Egypt and Lower Nubia as early as the Early Dynastic Period (3200–3050 bce) saw the evolution of rock art from the “Preformal artistic stage” to a “Formal canonical phase” and became standardized and formalized, such a conclusion would be unsuitable for Upper Nubia, in which the evolution of rock art occurred in entirely different cultural circumstances. International activities aimed at rescuing Nubia’s heritage, under the auspices of the Merowe Dam Archaeological Salvage Project (MDASP), has led to the discovery of many sites with rock art and to recording changes that occurred in the cultural landscape of the Fourth Nile Cataract over the course of several thousand years. This has provided reliable foundations for an analysis of the changes to Upper Nubian rock art within its specific archaeological and historical context and environmental setting.

Building Component Detection on Unstructured 3D Indoor Point Clouds Using RANSAC-Based Region Growing

With the advancement of light detection and ranging (LiDAR) technology, the mobile laser scanner (MLS) has been regarded as an important technology to collect geometric representations of the indoor environment. In particular, methods for detecting indoor objects from indoor point cloud data (PCD) captured through MLS have thus far been developed based on the trajectory of MLS. However, the existing methods have a limitation on applying to an indoor environment where the building components made by concrete impede obtaining the information of trajectory. Thus, this study aims to propose a building component detection algorithm for MLS-based indoor PCD without trajectory using random sample consensus (RANSAC)-based region growth. The proposed algorithm used the RANSAC and region growing to overcome the low accuracy and uniformity of MLS caused by the movement of LiDAR. This study ensures over 90% precision, recall, and proper segmentation rate of building component detection by testing the algorithm using the indoor PCD. The result of the case study shows that the proposed algorithm opens the possibility of accurately detecting interior objects from indoor PCD without trajectory information of MLS.