Tag: video

Potassium Pools

Potassium ions are vital for the functioning of all living cells. The transfer of potassium ions across nerve cell membranes is necessary for normal nerve transmission; potassium deficiency and excess can each result in numerous signs and symptoms, including an abnormal heart rhythm and various electrocardiographic abnormalities. Fresh fruits and vegetables are good dietary sources of potassium. The body responds to the influx of dietary potassium, which raises serum potassium levels, with a shift of potassium from outside to inside cells and an increase in potassium excretion by the kidneys.

First Applied Geometry

Researchers have made a discovery that may shake up the history of mathematics, revealing evidence of applied geometry being used for the purposes of land surveying 3.7 ka BP. Found on a Babylonian clay table, the etchings are believed to represent the oldest known example of applied geometry, and feature mathematical techniques linked to the Greek philosopher Pythagoras that were well ahead of their time.

Grabby Aliens

Advanced aliens really are out there, and we have enough data to say roughly where they are in space and time, and when we will meet or see them. In our model, GCs are born according to a volume-based power law, and once born they simply expand at a constant speed relative to local materials. We show that for nontrivial powers this power law is a reasonable approximation to a more realistic model. This expansion speed and the 2 parameters of this power law are the only 3 parameters of our model, each of which can be estimated from data to within 4x. The hard-steps in Earth history literature helps to estimate the power, and our current date helps to estimate the power law timescale. Furthermore, the fact that we do not now see large alien-controlled volumes in our sky, even though they should control much of the universe volume now, gives us our last estimate, that aliens expand at > 50% of lightspeed. Given estimates of all 3 parameters, we have in this paper shown many model predictions regarding alien timing, spacing, appearance, and the durations until we see or meet them. And we have shown how optimism regarding humanity’s future is in conflict with optimism regarding SETI efforts. Being especially simple, our model is unlikely to be an exact representation of reality. So future research might explore more realistic variations. For example, one might more precisely account for the recent exponential expansion of the universe, and for deviations between a realistic appearance function and our power law approximation. Instead of being uniform across space, the GCs birth rate might be higher within galaxies, higher within larger galaxies, and follow their typical spatial correlations. A GC expansion might take a duration to bring its full effect to any one location, and the GC expansion speed might vary and depend on local geographies of resources and obstacles. Finally, GC subvolumes might sometimes stop expanding or die, either spontaneously or in response to local disturbances.

2023-04-11: A good summary of the argument

Analog Fractals

All the images in this video are created by video feedback only – no computers are involved. The upper and lower monitors both display the same thing – the image from the camera, which is looking at the upper monitor. This creates a video feedback loop. It’s a delicate art to operate the device, an interplay between the camera and monitors, the position of the monitors, and the monitor control dials (hue, saturation, brightness and contrast). Doing controlled feedback like this requires these control dials, but most HD TVs and monitors don’t have analog knobs like old CRT TVs did, making it difficult to create controlled feedback in HD.

Cockatoo Culture

Even when residents in these areas weigh down the tops of their bins with bricks or stones, cockatoos have figured out how to knock these heavy objects to the ground. Once that barrier is removed, the hungry birds can crack the lid open with their beak, prop it on their heads and walk it back until it fully flips on its hinges, as the videos show below. This unique skill has now become so widespread in Sydney, researchers think the parrots are imitating and learning from one another – a sign of cultural evolution.

Completed Human Genome

The development of a reference genome was absolutely critical for progress in human genomics, and was of central importance in the sequencing revolution, serving as a foundational tool for sequencing alignment methods as well as genome assembly methods. The initial draft of the human genome and all following patch updates have consisted of the euchromatic regions, which comprises roughly 92% of the genome. Addressing this remaining 8% of the genome, the Telomere-to-Telomere (T2T) Consortium has finished the first truly complete 3.055b base pair sequence of a human genome, representing the largest improvement to the human reference genome since its initial release. A crucial aspect to realize about making improvements to the reference genome is that it has tremendous downstream impact for research and engineering in genomics. Because it is such a foundational coordinate system, it impacts everything that relies on it. This means that all new sequencing data can be more accurately mapped with a complete reference.

2023-05-13: We keep “completing” the human genome, now with more pangenome.

Reference genomes are crucial coordinate systems for genomic analyses. However, the references that scientists currently work from when studying humans (the draft human genome and its complete, gap-free successor, dubbed T2T-CHM13) are both based mostly on single individual genomes. A linear genome sequence of this type cannot adequately represent genetic diversity within our species. Instead, such diversity is more accurately described using a graph-based system of branching and merging paths, the first human reference pangenome. Using the pangenome for read mapping and variant calling resulted in 34% fewer errors in calling small variants (those shorter than 50 bases) than did using a linear reference. The difference was particularly pronounced in challenging repetitive DNA regions. Impressively, the pangenome identified 2x as many large genomic alterations, called structural variants, per person than is possible using a linear reference. However, challenges remain. Alignment of sequences against highly variable repetitive regions in the pangenome could be improved by more-accurate assemblies or new algorithms. More samples from diverse groups are also needed. Finally, widespread adoption of the pangenome by scientists could take time, because new methods supporting pangenome analysis are continually being developed, and scientists will often require training to use them.


2023-08-31: Even more complete, now with more Y chromosome

The human Y chromosome has been notoriously difficult to sequence and assemble because of its complex repeat structure that includes long palindromes, tandem repeats and segmental duplications. As a result, more than half of the Y chromosome is missing from the GRCh38 reference sequence and it remains the last human chromosome to be finished. Here, the Telomere-to-Telomere (T2T) consortium presents the complete sequence of a human Y chromosome from the HG002 genome (T2T-Y) that corrects multiple errors in GRCh38-Y and adds over 30n base pairs of sequence to the reference, showing the complete ampliconic structures of gene families TSPY, DAZ and RBMY; 41 additional protein-coding genes, mostly from the TSPY family; and an alternating pattern of human satellite 1 and 3 blocks in the heterochromatic Yq12 region. We have combined T2T-Y with a previous assembly of the CHM13 genome4 and mapped available population variation, clinical variants and functional genomics data to produce a complete and comprehensive reference sequence for all 24 human chromosomes.

Sophia

unclear how staged this is, but impressive either way.

Little Sophia can walk, talk, sing, play games and, like her big sister, tell jokes. With Little Sophia’s software, and included tutorials through Hanson’s AI Academy, she is a unique programmable, educational companion for kids, inspiring children to learn through a safe, interactive, human-robot experience

Leaky pipes

Researchers have taken inspiration from trees and developed a system for moving water around that depends on capillary action and surface tension. They 3D printed tiny open-faced cells that can expose a large surface area of water to the surrounding gas – which could be useful for things like cooling or gas exchange systems. Their pipes had 3x better performance.

Switched Reluctance Motors

The switched reluctance motor (SRM) is an electric motor that runs by reluctance torque. Unlike common brushed DC motor types, power is delivered to windings in the stator (case) rather than the rotor. This greatly simplifies mechanical design as power does not have to be delivered to a moving part, but it complicates the electrical design as some sort of switching system needs to be used to deliver power to the different windings. They are 50% more efficient, and if deployed in the US, would save enough carbon to equal 1 Amazon forrest