Honey bees build complexes of hexagonal wax cells in their nests to contain their larvae and stores of honey. Why do these insects prefer hexagons to, for instance, square cells (which are more straightforward to build)?
There are two possible explanations. One is that hexagon tiles the plane with minimal surface area. This claim (for obvious reasons called the “honeycomb conjecture”) was proved only in 1999 by Thomas Hales, and implies the hexagonal structure uses the least material to create a lattice of cells within a given volume.
Another explanation is that the hexagonal shape simply results from the process of individual bees putting cells together, somewhat analogous to the boundary shapes created in a field of soap bubbles. In support of this theory, it is observed that queen cells, which are constructed singly, are irregular, with no apparent attempt at efficiency.
Chat Noir looked up from the chaise in Marinette’s bedroom to find her looking at him with piercingly blue eyes. He looked down at his hand, fingers tipped with claws, and skin covered in the fine black tessellating hexagons of his suit. He’d wondered about it himself, but Plagg had been uniquely uninformative about the limitations of his strengths, and weaknesses.
“No,” he said, after thinking about it. Marinette tilted her head at him, and he sat up, flexing his fingers, thoughtfully. “Things hurt,” he admitted, “but not as much as you’d think.” He’d been thrown off a building, and could bounce across the road without so much as a bruise, although they hadn’t exactly been comfortable. “The suit’s magic,” he said, softly, “it protects me from a lot.”
Marinette hummed, wordlessly, and turned back to her homework. He’d told her he’d sit patiently and wait for her to finish it, because he wouldn’t be responsible for her being grounded on account of poor grades. He’d planned to let her finish it, without interrupting her, but the question, and subsequent murmur, made that difficult.
“Worried about me, Princess?”
“Yes.” He hadn’t expected that answer, and he looked at her as if seeing her for the first time. She wasn’t looking at him, but he got the impression she was deliberately not looking at him, rather than concentrating hard on her studies.
“Don’t be,” he said, eventually.
“You’re too self sacrificing,” she replied, her voice suddenly quiet. “You take hits for Ladybug all the time. I just,” she trailed off, her head bowing slightly, “wondered if they hurt.”
Chat felt his throat tighten as he looked at Marinette. He tried to reply, but found his jaw worked uselessly until he grit his teeth, his shoulders slumping. “They don’t hurt,” he said, finally. Much.
Marinette nodded, the corner of her mouth twitching faintly in a sad smile. “At least there’s that.”
The cognitive map for spatial navigation is thought to rely on grid
cells. Scientists at LMU and Harvard University have now put forward a
mathematical theory that explains key grid-cell features and how these
give rise to a neural metric for space.
One year ago, the Nobel Prize in Physiology or Medicine went to the
discoverers of the mammalian “GPS system” for spatial navigation.
Measuring neural activity in cortex, these researchers had found that
some cells represent space in a highly surprising manner: As the animal
moves through its environment, distinct sets of cells are sequentially
activated. Each individual “grid cell” responds to multiple positions in
space that form a virtual hexagonal lattice tessellating the
environment. This strikingly periodic and beautiful spatial pattern has
caught the imagination of experimental and theoretical neuroscientists
alike, and has been proposed to constitute the brain’s metric for space.
Theoretical neuroscientists at LMU Munich and the Bernstein Center
for Computational Neuroscience in Munich, and at Harvard University,
have now put forward a comprehensive mathematical theory that explains
many features of grid cell activity that had remained mysterious, and
makes specific predictions that can be tested in neurophysiological and
behavioral experiments. The framework proposed by Martin Stemmler (LMU), Alexander Mathis (Harvard) and Andreas V.M. Herz
(Professor of Computational Neuroscience at LMU) exploits and extends a
computational principle well known from sensory systems and the brain’s
motor cortex – population-vector decoding: physical quantities such as
the angle of a visual stimulus or the direction of a movement can be
easily read out from the activity of a population of neurons with
different tuning properties if the neurons’ activities are combined in a
particular, vector-like manner.
However, the theory proposed by Stemmler and colleagues goes far
beyond these previous schemes in that the decoded quantity – the
animal’s position – is not a circular variable. “Animals move on
two-dimensional surfaces or in three-dimensional spaces, so their
position is not a one-dimensional variable either. In addition,
population-vector averages across different grid scales need to be
combined,” explains Andreas Herz. Yet, the overall conceptual similarity
of the new scheme to conventional population-vector decoding suggests
that there exist overarching computational principles that operate
throughout the brain. “This raises hopes that, in spite of the brain’s
complexity, a thorough understanding of the neural basis of many
cognitive processes is possible.”
Thanks to the new theory, three basic questions can now be readily
answered: Why are grid cells organized into discrete modules, within
which all grid lattices share the same spatial scale and orientation,
but have different spatial offsets? Why do the spatial scales of the
grid lattices form a geometric progression? And why is the observed
scale ratio close to 3/2? “If grid cells were not organized into modules
with fixed grid scale and orientation, the brain could not use
population vectors to represent spatial position,” explains Martin
Stemmler. “The geometric progression in the grid scales maximizes the
spatial resolution of the neural code, based on just a few bursts of
neural activity. Finally, the scale ratio should be close to 3/2 to
avoid large-scale errors when information from different grid modules is
combined to calculate a single quantity, the animal’s position
The theory also shows that grid cells can be used not only to
estimate position in world-centered coordinates, but also to tell the
direction to some goal – for example, a food source or the animal’s home
– in self-centered coordinates, a key requirement for navigation.
“Transiently silencing individual grid modules should lead to specific
types of navigational errors – a prediction that can be tested in future
research”, says Alexander Mathis. Perhaps most importantly, the new
work translates the hitherto rather hazy notion of “a neural metric for
space” into a precisely defined mathematical framework. The results have
already helped to settle a recent controversy in the field – whether
the observed distortions of grid patterns falsify the proposed role of
grid cells as a metric for space (no, they don’t) – and will, most
probably, also guide future experiments.
UNBREAKABLE GLASS WITH HONEYCOMB STRUCTURED ULTRA RUBBER
As a passionate scientist, I know lab accidents happen sometimes. What if a piece of technology could change our lives forever? Introducing Honeycomb Structured Ultra Rubber - a substance that covers glass and renders it unbreakable.
WHAT INSPIRED HSCU?
It’s called the honeycomb structure. Using a tessellated hexagonal pattern, it creates a structure with minimal density and high compression properties. In other words, it’s cheap and it’s strong. Next step was finding the perfect material.
Steel? Too tough. Gold? Sweet, but expensive. Silicone rubber, perfect. The large bond angles and siloxane (sil-OX-ane) backbone make silicone rubber a highly flexible polymer. The perfect stretchy material to cover the glass itself. Voila. No more broken glass.
WHY DO YOU NEED TO SUPPORT?
Now, you might be asking yourself “Why can’t this sexy fella just fund his own project?” Well, this sexy fella’s money was stolen by a psychopathic super villain with half a face.
Tune in on Thursdays to watch the development progress.
THE MAN BEHIND HSUR
Jack Hodgins. Botanist, entomologist, sex symbol, some say (Angela), and now, inventor.