Infinity: some close encounters in physics teaching

This paper describes two examples of teaching situations in which the idea of infinity arises, and supports the conclusion that infinity is not a physical reality but a very powerful and useful mathematical device which facilitates modelling and the solution of problems in physics.

The Second Earth Trojan 2020 XL5

The Earth Trojans are coorbitals librating around the Lagrange points L 4 or L 5 of the Sun–Earth system. Although many numerical studies suggest that they can maintain their dynamical status and be stable on timescales up to a few tens of thousands of years or even longer, they remain an elusive population. Thus far only one transient member (2010 TK7) has been discovered serendipitously. Here, we present a dynamical study of asteroid 2020 XL5. With our meticulous follow-up astrometric observations of the object, we confirmed that it is a new Earth Trojan. However, its eccentric orbit brings it close encounters with Venus on a frequent basis. Based on our N-body integration, we found that the asteroid was captured into the current Earth Trojan status in the fifteenth century, and then it has a likelihood of 99.5% to leave the L 4 region within the next ∼10 kyr. Therefore, it is most likely that 2020 XL5 is dynamically unstable over this timescale.

The Impact of Ambassador Animal Facilitated Programs on Visitor Curiosity and Connections: A Mixed-Methods Study

Many zoos and aquariums offer opportunities for visitors to have up-close encounters with ambassador animals; however, the impacts of these experiences on visitors’ connections to animals are not well documented. We used observations and family interviews in a sequential mixed-methods research study to explore how animal ambassador programs impact participants. We found that the type of ambassador animal did not affect the number of questions or comments made by participants during programs, suggesting broad interest in animals. Programs in which facilitators prompted participants with questions were especially successful at eliciting questions and guiding the topics of those questions, fueling deeper curiosity. Interviewees described themselves as “animal people” and self-reported practicing conservation behaviors, suggesting that their animal affiliative and pro-environmental identities could be leveraged to discuss conservation issues and encourage solutions-based behaviors. Lastly, opportunities to meet ambassador animals increased participants’ feelings of connecting to animals, building on previous research and corroborating findings. Programs should consider how to further build on these positive learning and affective outcomes by capitalizing on opportunities to provide deep insights into conservation issues and actions related to the ambassador animals.

The Aesthetics of Proximity and the Ethics of Empathy

Where does affect reside in a phenomenology of perception? How should we understand ethics when bodies are close? What changes when we are distant? In this chapter, the author illustrates the “aesthetics of proximity,” degrees of spatio-temporal as well as spatio-tactile closeness between sounds and bodies, and the implications for an embodied ethics of response. Using Merleau-Ponty’s notion of the “flesh,” which he defines as an element (like water or fire), the author explores the relation of feeling and matter in close encounters, evoking Sufi sounds of worship in Morocco and France, as well as the Black Lives Matter movement during a global pandemic.

Immune Checkpoint Therapy: Tumor Draining Lymph Nodes in the Spotlights

Tumor-draining lymph nodes play a paradoxical role in cancer. Surgeons often resect these sentinel lymph nodes to determine metastatic spread, thereby enabling prognosis and treatment. However, lymph nodes are vital organs for the orchestration of immune responses, due to the close encounters of dedicated immune cells. In view of the success of immunotherapy, the removal of tumor-draining lymph nodes needs to be re-evaluated and viewed in a different light. Recently, an important role for tumor-draining lymph nodes has been proposed in the immunotherapy of cancer. This new insight can change the use of immune checkpoint therapy, particularly with respect to the use in neoadjuvant settings in which lymph nodes are still operational.

Close encounters with scientific analogies of the third kind

Arguments from non-causal analogy form a distinctive class of analogical arguments in science not recognized in authoritative classifications by, e.g., Hesse (1963) and Bartha (2009). In this paper, I illustrate this novel class of scientific analogies by means of historical examples from physics, biology and economics, at the same time emphasizing their broader significance for contemporary debates in epistemology.