Lifeboat Foundation

The size of a cell is determined by a combination of synthesis, self-assembly, incoming matter and the balance of mechanical forces. Such processes operate at the single-cell level, but they are deeply interconnected with cell-cycle progression, resulting in a stable average cell size at the population level. Here, we examine this phenomenon by reviewing the physics of growth processes that operate at vastly different timescales, but result in the controlled production of daughter cells that are close copies of their mothers. We first review the regulatory mechanisms of size at short timescales, focusing on the contribution of fundamental physical forces. We then discuss the multiple relevant regulation processes operating on the timescale of the cell cycle. Finally, we look at how these processes interact: one of the most important challenges to date involves bridging the gap between timescales, connecting the physics of cell growth and the biology of cell-cycle progression.

Great discuss of time travel by Dr. Brain greene.

A trio of physicists from the National Autonomous University of Mexico and Tec de Monterrey has solved a 2,000-year-old optical problem—the Wasserman-Wolf problem. In their paper published in the journal Applied Optics, Rafael González-Acuña, Héctor Chaparro-Romo, and Julio Gutiérrez-Vega outline the math involved in solving the puzzle, give some examples of possible applications, and describe the efficiency of the results when tested.

Over 2,000 years ago, Greek scientist Diocles recognized a problem with optical lenses—when looking through devices equipped with them, the edges appeared fuzzier than the center. In his writings, he proposed that the effect occurs because the lenses were spherical—light striking at an angle could not be focused because of differences in refraction. Isaac Newton was reportedly stumped in his efforts to solve the problem (which became known as spherical aberration), as was Gottfried Leibniz.

In 1949, Wasserman and Wolf devised an analytical means for describing the problem, and gave it an official name—the Wasserman-Wolf problem. They suggested that the best approach to solving the problem would be to use two aspheric adjacent surfaces to correct aberrations. Since that time, researchers and engineers have come up with a variety of ways to fix the problem in specific applications—most particularly cameras and telescopes. Most such efforts have involved creating aspherical lenses to counteract refraction problems. And while they have resulted in improvement, the solutions have generally been expensive and inadequate for some applications.

BIG GULP Gravitational waves may have revealed a black hole in the process of swallowing up a neutron star (illustrated). If confirmed, the event would be the first of its kind ever seen.

The prospect of reliving a past moment from Earth’s amazing history or skipping ahead of the future is a tantalising idea widely present in science fiction. But physicists who spend their days pondering the mysteries of time and space believe time travel might be within the realm of possibility. This does not mean scientists will develop TARDIS-like time travel machines straight out of Dr Who any time soon. Instead, the theoretical and physical frameworks are there to show moving forward in time can be achieved – with a small catch.

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What. The. Heck. Did you see that? Simone Biles appears to defy the laws of physics with this epic tumbling pass from the 2019 US Gymnastics Championships. It’s called a triple-double. That means she rotates around an axis going through her hips twice while at the same time rotating about an axis going from head to toe THREE times. Yes, it’s difficult—but it doesn’t defy physics, it uses physics.

Forget the gold medals, GIVE THIS WOMAN A CROWN 👑@Simone_Biles makes history (again) as the first woman to land a triple double in competition on floor! 🔥 pic.twitter.com/TazpPJx41W— NBC Sports (@NBCSports) August 12, 2019

Continue reading “The Twisty Physics of Simone Biles’ Historic Triple-Double” »

Physicists Sergio Ferrara, Dan Freedman, and Peter van Nieuwenhuizen will split a $3 million Breakthrough Prize for their theory of supergravity, which drives much of today’s physics research toward our understanding of the universe.

The Breakthrough Prize is an annual award to recognize groundbreaking science, funded by Russian-Israeli billionaire Yuri Milner. Though Breakthrough Prizes are awarded annually, “special” Breakthrough Prizes can be awarded any time and need not honor recent work. In fact, the researchers behind today’s award thought they’d missed the chance to win it.

The human brain contains a little over 80-odd billion neurons, each joining with other cells to create trillions of connections called synapses.

The numbers are mind-boggling, but the way each individual nerve cell contributes to the brain’s functions is still an area of contention.

In fact, a study published in 2017 has overturned a 100-year-old assumption on what exactly makes a neuron ‘fire’, posing new mechanisms behind certain neurological disorders.