A Star Harbouring a Wormhole at its Core

We consider a configuration consisting of a wormhole filled by a perfect fluid. Such a model can be applied to describe stars as well as neutron stars with a nontrivial topology. The presence of a tunnel allows for motion of the fluid, including oscillations near the core of the system. Choosing the polytropic equation of state for the perfect fluid, we obtain static regular solutions. Based on these solutions, we consider small radial oscillations of the configuration and show that the solutions are stable with respect to linear perturbations in the external region.Comment: abstract was change

3D sound for simulation of arthroscopic surgery

Arthroscopic surgery offers many advantages compared to traditional surgery. Nevertheless, the required skills to practice this kind of surgery need specific training. Surgery simulators are used to train surgeon apprentices to practice specific gestures. In this paper, we present a study showing the contribution of 3D sound in assisting the triangulation gesture in arthroscopic surgery simulation. This ability refers to the capacity of the subject to manipulate the instruments while having a modified and limited view provided by the video camera of the simulator. Our approach, based on the use of 3D sound metaphors, provides interaction cues to the subjects about the real position of the instrument. The paper reports a performance evaluation study based on the perception of 3D sound integrated in the process of training of surgical task. Despite the fact that 3D sound cueing was not shown useful to all subjects in terms of execution time, the results of the study revealed that the majority of subjects who participated to the experiment confirmed the added value of 3D sound in terms of ease of use

Arquitectura de microservicios para una plataforma de gestión remota para la cría de aves en pastoreo utilizando Amazon Web Services y redes inalámbricas de sensores de malla

Introduction: A variety of innovative solutions known as Precision Livestock Farming (PLF) technologies have been developed for the management of animal production industries, including Wireless Sensor Networks (WSN) for poultry farming. Problem: Current WSN-based systems for poultry farming lack the design of robust but flexible software architectures that ensure the integrity and proper delivery of data. Objective: Designing a microservice-based software architecture (MSA) for a multiplatform remote environmental management system based on Wireless Mesh Sensor Networks (WMSN) to be deployed in pastured poultry farming spaces. Methodology: A review about MSAs designed for animal farming was conducted, to synthesize key factors considered for the design process of the system data flow, microservice definition and the environmental monitoring system technology selection. Results: A cloud MSA with a multi layered scheme using the Amazon Web Services (AWS) platform was developed, validating the persistence of environmental data transmitted from WMSN prototype nodes to be deployed in mobile chicken coops. Conclusion: Defining an End-to-End data flow facilitates the organization of tasks by domains, allowing efficient event communication between components and network reliability both at the hardware and software levels. Originality: This study presents a novel design for a remote environmental monitoring system based on WMSN for mobile coops used in pastured poultry and a multi layered MSA cloud management platform for this specific type of food production industry. Limitations: Software architecture technology selection was based only on services offered, to the date of the study, in the free tier of the Amazon Web Service platform.Introducción: arquitectura de microservicios para una plataforma de gestión remota para la avicultura en pastoreo utilizando Amazon Web Services y redes inalámbricas de sensores de malla, Universidad Tecnológica de Panamá, 2023. Problema: las tecnologías de ganadería de precisión (PLF) ayudan a la gestión de las industrias de producción animal, como el uso de redes de sensores inalámbricos (WSN) en la cría de aves de corral. Los sistemas actuales basados en WSN para la cría de aves de corral carecen de arquitecturas de software sólidas pero flexibles para garantizar la integridad y la entrega adecuada de los datos. Objetivo: diseñar una arquitectura de software basada en microservicios (MSA) para un sistema de gestión ambiental remota basado en Wireless Mesh Sensor Networks (WMSN) para aves en pastoreo. Metodología: se realizó una revisión de MSA para la cría de animales para sintetizar los factores clave considerados en el proceso de diseño del flujo de datos del sistema, la definición de microservicios y la selección de tecnología del sistema de monitoreo ambiental. Resultados: se desarrolló un MSA en la nube con esquema multicapa utilizando la plataforma Amazon Web Services (AWS), validando la persistencia de datos ambientales de nodos prototipo WMSN para ser desplegados en gallineros móviles. Conclusión: definir un flujo de datos End-to-End facilita la organización de tareas por dominio, permitiendo una comunicación eficiente de eventos entre componentes y confiabilidad de la red tanto a nivel de hardware como de software. Originalidad: este estudio presenta un diseño novedoso para un sistema de monitoreo ambiental remoto basado en WMSN para cooperativas móviles utilizadas en aves de pastoreo y una plataforma de administración en la nube MSA de varias capas para esta industria.

JME 4110 Seed Aerodynamics

This is a report discussing the analysis and results of a wind tunnel that was created to find the terminal velocity of a variety of seeds

On the mass assembly of low-mass galaxies in hydrodynamical simulations of structure formation

Cosmological hydrodynamical simulations are studied in order to analyse generic trends for the stellar, baryonic and halo mass assembly of low-mass galaxies (M_* < 3 x 10^10 M_sun) as a function of their present halo mass, in the context of the Lambda-CDM scenario and common subgrid physics schemes. We obtain that smaller galaxies exhibit higher specific star formation rates and higher gas fractions. Although these trends are in rough agreement with observations, the absolute values of these quantities tend to be lower than observed ones since z~2. The simulated galaxy stellar mass fraction increases with halo mass, consistently with semi-empirical inferences. However, the predicted correlation between them shows negligible variations up to high z, while these inferences seem to indicate some evolution. The hot gas mass in z=0 halos is higher than the central galaxy mass by a factor of ~1-1.5 and this factor increases up to ~5-7 at z~2 for the smallest galaxies. The stellar, baryonic and halo evolutionary tracks of simulated galaxies show that smaller galaxies tend to delay their baryonic and stellar mass assembly with respect to the halo one. The Supernova feedback treatment included in this model plays a key role on this behaviour albeit the trend is still weaker than the one inferred from observations. At z>2, the overall properties of simulated galaxies are not in large disagreement with those derived from observations.Comment: 19 pages, 12 figures. Accepted for publication in MNRAS: 6th August 2013. First submitted: 7th July 201