Catálogo de publicaciones - revistas

<jats:p>In electromagnetism courses, students often solve Poisson's equation for a point charge in the presence of an infinitely large perfectly conducting planar surface, usually by the method of images. However, no surface is perfectly flat; so at some level, corrugations must be introduced to model the real world. Clinton et al. [Phys. Rev. B 31, 7540 (1985)] solved the problem, including corrugations, using a perturbative calculation of the corresponding Green's function. We provide a detailed pedagogical review of this calculation and extend it in order to solve for the electrostatic potential of a corrugated neutral conducting cylinder in the presence of a uniform electric field. These calculations can be used as pedagogical examples of this perturbative approach in electromagnetism courses.</jats:p>

<jats:p>The methods devised by Gustav Mie in 1908 to explain the scattering of electromagnetic waves have a close analogy with quantum-mechanical models developed many years later to describe nuclear scattering. In particular, these models use either a complex index of refraction or a complex nuclear scattering potential to account for attenuation caused by non-elastic scattering. We briefly outline the historical development of these models and give examples illustrating the close analogy between them, their parameters, and the resulting scattering. In both models, the ratio of the incident wavelength to the object size, λ/D, can be determined from the scattering characteristics, allowing the extraction of microscopic particle dimensions. This close analogy allows students to simulate accelerator-based nuclear scattering experiments with table-top optical-scattering experiments.</jats:p>

<jats:p>The recently unveiled deep-field images from the James Webb Space Telescope have renewed interest in what we can and cannot see of the universe. Answering these questions requires understanding the so-called “cosmological horizons” and the “Hubble sphere.” Here, we review the topic of cosmological horizons in a form that university physics teachers can use in their lessons, using the latest data about the so-called standard “Lambda cold dark matter” (ΛCDM) model. Graphical representations are plotted in terms of both conformal and proper coordinates as an aid to understand the propagation of light in the expanding universe at various epochs.</jats:p>

<jats:p>Search processes are ubiquitous in physical and biological phenomena, often involving the random motion of molecules. In particular, transcription factors (TFs) are proteins that regulate gene expression and need to find their DNA targets quickly—which is difficult to achieve with random motion alone. Nature came up with a remarkable solution known as facilitated diffusion, combining 1D diffusion along the DNA and “excursions” of diffusion in 3D that help the TF to quickly arrive at distant parts of the DNA. In this paper, we show that this process can be analyzed naturally using the concept of conditional probability, providing an alternative intuition to the effectiveness of this mechanism.</jats:p>

<jats:p>We present an intermediate-level course on sustainable physics, which combines lectures and student projects. Sustainable physics concepts are progressively introduced through both a global and a specialized perspective: climate change and building design. The lectures and hands-on activities on both topics show how they share common concepts and provide complementary points of view. Climate change mitigation and adaptation are touched on via student group projects, where they are asked to tackle a specific question of their choosing via reviews of the literature, modeling, or experiments.</jats:p>

<jats:p>We describe a collection of relatively simple experiments and laboratory demonstrations devoted to the physics of Earth's energy balance. Many of the experiments also address fundamental aspects of physics at the undergraduate level. Results of classroom testing of this sequence of activities are presented and discussed.</jats:p>

<jats:p>We developed a two-day physics class that uses a nearby forest as a teaching location. Using low-cost material, students design and carry out physics projects outside of the usual controlled environment that is a classroom. In this way, they come to realize that physics can be used to understand the real world. They organize and present their results in an original format, an exhibit they collectively build. This project is an introduction to the role physics can play in exploring environmental issues, incorporating a sensitive and positive aspect which is important in this time of environmental crisis.</jats:p>

<jats:p>This article describes a learner-centered, tutorial-based approach to climate modeling. Using these tutorials, students in a general education course in global climate change taught in the physics department engaged with compelling, “real-world” questions by drawing on foundational physics concepts along with their prior experiences and conceptual resources in the process of knowledge construction. Students used simulations, energy tracking diagrams, and algebraic analysis to construct climate models that address challenging quantitative questions and reveal key concepts in climate science. Special emphasis was given to the learning goals, pre-requisite knowledge, and conceptual challenges associated with these activities. Instructional materials are provided for educators who wish to adapt these tutorials for use in their own educational context. The supplementary materials are appropriate for both non-science majors and upper-level physics majors.</jats:p>