Human sperm have a unique ability to swim through highly viscous fluids with ease, defying Newton’s third law of motion in the process. A team led by Kenta Ishimoto, a mathematical scientist at Kyoto University, conducted a study a few years ago to investigate how sperm and other microscopic biological swimmers navigate through substances that should impede their movement.
One of the fundamental principles of physics, Newton’s third law states that for every action, there is an equal and opposite reaction. This law governs the interactions between physical objects and the forces acting upon them. However, when it comes to microscopic cells like sperm, this law doesn’t always hold true.
In chaotic systems like those involving flocking birds, particles in fluid, and swimming sperm, non-reciprocal interactions occur, leading to asymmetric movements that defy Newton’s third law. These motile agents generate their own energy, which constantly adds to the system with each movement, pushing it far from equilibrium.
In their study published in October 2023, Ishimoto and his colleagues analyzed experimental data on human sperm and modeled the motion of green algae, Chlamydomonas. Both sperm and algae swim using thin, bendy flagella that change shape to propel them forward. Despite being in highly viscous fluids that would typically impede their movement, the elastic flagella of these cells allow them to move without much energy loss.
The researchers discovered that sperm tails and algal flagella possess an “odd elasticity,” which enables them to move through fluids without resistance. Additionally, they introduced a new term, an odd elastic modulus, to describe the internal mechanics of flagella that contribute to their propulsion.
These findings could have implications for the design of small, self-assembling robots that mimic living materials. The modeling methods used in the study could also enhance our understanding of collective behavior in biological systems.
The study was published in PRX Life, and it sheds light on the unique mechanics that enable sperm and other microscopic swimmers to navigate through viscous fluids with ease. This research opens up new possibilities for bio-inspired technologies and deepens our knowledge of the underlying principles of movement in biological systems. As the world continues to grapple with the effects of the COVID-19 pandemic, businesses are faced with unique challenges and opportunities. One sector that has been particularly impacted is the travel industry, as international borders remain closed and travel restrictions are in place. However, as the situation slowly begins to improve with the rollout of vaccines and the gradual reopening of economies, there is hope on the horizon for the travel industry.
One key trend that has emerged in the wake of the pandemic is the rise of domestic tourism. With international travel still limited, many people are opting to explore their own countries and support local businesses. This has led to a surge in demand for domestic travel options, such as road trips, staycations, and outdoor adventures. Hotels, resorts, and tour operators that focus on domestic tourism are seeing an increase in bookings and revenue, signaling a shift in consumer preferences.
Another trend that has gained momentum is the rise of sustainable travel. The pandemic has brought into focus the impact of travel on the environment, and travelers are now more conscious of their carbon footprint. As a result, there is a growing demand for eco-friendly travel options, such as carbon-neutral accommodations, electric vehicle rentals, and sustainable tours. Businesses that prioritize sustainability and environmental responsibility are likely to attract more customers and gain a competitive edge in the post-pandemic travel industry.
In addition to domestic tourism and sustainable travel, technology is also playing a crucial role in shaping the future of the travel industry. With the rise of contactless check-ins, digital health passports, and virtual experiences, technology is transforming the way we travel. Virtual reality tours, online booking platforms, and AI-powered travel assistants are just some of the innovations that are revolutionizing the travel experience and making it more convenient and accessible.
As the travel industry adapts to the new normal, businesses are also focusing on health and safety measures to reassure travelers and rebuild trust. Enhanced cleaning protocols, social distancing guidelines, and flexible cancellation policies are becoming standard practices for hotels, airlines, and tour operators. Building a safe and secure travel environment is essential for attracting customers and ensuring their peace of mind during their journeys.
Overall, the future of the travel industry post-pandemic is evolving as businesses embrace new trends, technologies, and strategies to meet the changing needs and preferences of travelers. By focusing on domestic tourism, sustainability, technology, and health and safety, businesses can position themselves for success in the post-pandemic world. As the world slowly recovers from the pandemic, the travel industry has the opportunity to reinvent itself and emerge stronger than ever before.
