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giovedì 30 luglio 2020

# GST: apropos of the search of anomalies

<< I think in many respects, anomalies are a good driver of scientific creativity,  It’s like a paradox; you have to resolve it >> David Ireland

<< Anomalies force experimentalists to find ways of reducing systematic uncertainties, analyzing their data, and conducting more precise searches. Theorists, meanwhile, must grapple with anomalous results by building models that often assume new (..), >>

<< Particle physicists are faced with a growing list of “anomalies” — experimental results that conflict with the standard model but fail to overturn it for lack of sufficient evidence. >>

Dan Garisto. The Era of Anomalies. Physics 13, 79. May 14, 2020.


mercoledì 29 luglio 2020

# gst: controlling particles with sound waves

<< Contactless manipulation of particles and cells using sound radiation forces that can be tuned and adjusted in real time has become important in various applications  (display tech, biomed sensors, imaging devices, diagnostic tools) >>

AA << use phononic crystals to tune sound fields in a microfluidic channel for controllable manipulation of microparticles and cells. An arbitrary stop-and-go motion of particles and cells along a predefined path in the channel is experimentally demonstrated. >>

Fei Li, Feiyan Cai, et al.  Phononic-Crystal-Enabled Dynamic Manipulation of Microparticles and Cells in an Acoustofluidic Channel.  Phys. Rev. Applied 13, 044077. Apr 30, 2020.


Controlling Particle Movements with Sound Waves. Physics 13, s58. Apr 30, 2020.



sabato 25 luglio 2020

# gst: a simple signal to drive complex dynamics

<< a developmental signaling pattern can be erased and replaced with a synthetic, patterned stimulus. (..) unlike pharmacological or genetic perturbations, light can be applied and removed quickly, focused with high spatial precision, or shaped into arbitrary spatial patterns. (AA) found that a simple all-or-none blue light stimulus, delivered to the embryonic termini, is sufficient to convert a lethal loss-of-function phenotype to rescue the full Drosophila life cycle: embryogenesis; larval development; pupation; adulthood; and fecundity. >>

<<  Such optical control over development could be used to probe cell and tissue-level regulation, engineer tissue organization, and correct developmental defects. >>

Heath E. Johnson, Nareg J.V. Djabrayan, et al. Optogenetic Rescue of a Patterning Mutant. Current Biology. 30, 1-11. doi: 10.1016/ j.cub.2020.06.059. Jul 23, 2020. 


Complex developmental patterns are under the control of surprisingly simple signals. Princeton University. Jul 23, 2020.


Also

keyword 'signal' in FonT


keyword 'signal' in Notes (quasi-stochastic poetry)





venerdì 24 luglio 2020

# life: high traffic, busy skies; every 6 months the Agency will publish news about TicTac Entities, UFOs, UAPs, ...

<< The Pentagon’s secretive UFO unit is going to make some of its findings public, The New York Times reported. And one consultant to the agency (Eric W. Davis, Astrophysicist) has briefed Defense Department officials of some highly unusual discoveries ― including items retrieved from “off-world vehicles not made on this Earth,” the newspaper said. >>

<< The military’s encounters with possible UFOs have come under intense interest since several videos were leaked in 2017 showing encounters with fast-moving objects including one given the nickname “Tic Tac” because it looked like one of the candies. This object, still not publicly identified, dropped from 60,000 feet to just 50 feet in a matter of seconds: “The part that drew our attention was how it wasn’t behaving within the normal laws of physics,” >> Chad Underwood, pilot. 

Ed Mazza. Explosive UFO Report In NYT Mentions ‘Off-World Vehicles Not Made On This Earth’. A Pentagon consultant made the revelation to The New York Times. Jul 24, 2020


<< It's not every day one reads a New York Times article containing the phrase “off-world vehicles not made on this earth". When I investigated UFOs for the UK government in the Nineties, I could only dream of such mainstream respectability for this subject. >> Nick Pope. 07:33 Jul 24, 2020. 


Also

keyword 'ufo' in FonT:


keyword 'ufo' in Notes (quasi-stochastic poetry):




giovedì 23 luglio 2020

# physics: SQUID, a probe at the boundary between 'quantum' and 'classic' worlds

<< A new device that relies on flowing clouds of ultracold atoms promises potential tests of the intersection between the weirdness of the quantum world and the familiarity of the macroscopic world we experience every day. The atomtronic Superconducting QUantum Interference Device (SQUID) is also potentially useful for ultrasensitive rotation measurements and as a component in quantum computers. >>

AA << created the device by trapping cold atoms in a sheet of laser light. A second laser intersecting the sheet "painted" patterns that guided the atoms into two semicircles separated by small gaps known as Josephson Junctions. When the SQUID is rotated and the Josephson Junctions are moved toward each other, the populations of atoms in the semicircles change as a result of quantum mechanical interference of currents through Josephson Junctions. By counting the atoms in each section of the semicircle, the researchers can very precisely determine the rate the system is rotating.>>

James Riordon. Atomtronic device could probe boundary between quantum, everyday worlds. Los Alamos National Laboratory. July 17, 2020.


C. Ryu, E. C. Samson, M. G. Boshier. Quantum interference of currents in an atomtronic SQUID. Nat Commun 11, 3338. doi: 10.1038/ s41467-020-17185-6. Jul 3, 2020.



martedì 21 luglio 2020

# gst: weird matter, the 'ballistic resonance' paradox; amplitude of mechanical vibrations can grow without external influence

AA << discovered a new physical phenomenon of 'ballistic resonance', where mechanical oscillations can be excited only due to internal thermal resources of the system. >>

<< The discovered phenomenon describes that the process of heat equilibration leads to mechanical vibrations with an amplitude that grows with time. The effect is called ballistic resonance. >>

<< Over the past few years, our scientific group has been looking into the mechanisms of heat propagation at the micro and nano levels. We found out that at these levels, heat doesn't spread in the way we expected it to: for example, heat can flow from cold to hot. This behavior of nanosystems leads to new physical effects, such as ballistic resonance, >> Vitaly Kuzkin.

Scientists have discovered a new physical paradox. Peter the Great Saint-Petersburg Polytechnic University. Jul 13, 2020.


<< coupling between macroscopic dynamics and quasiballistic heat transport gives rise to mechanical vibrations with growing amplitude. This phenomenon is referred to as ballistic resonance. At large times, these mechanical vibrations decay monotonically >>

Vitaly A. Kuzkin, Anton M. Krivtsov. 
Ballistic resonance and thermalization in the Fermi-Pasta-Ulam-Tsingou chain at finite temperature. Phys. Rev. E 101, 042209. Apr 16, 2020.



lunedì 20 luglio 2020

# gst: apropos of 'strange states', the modulation of PdGa crystals from conventional to 'exotic' behaviors

<< In topological materials, electrons can display behavior that is fundamentally different from that in 'conventional' matter, and the magnitude of many such 'exotic' phenomena is directly proportional to an entity known as the Chern number. New experiments establish for the first time that the theoretically predicted maximum Chern number can be reached—and controlled—in a real material. >>

<<  in the topological semimetal palladium gallium (PdGa) one of the most common classifiers of topological phenomena, the Chern number, can reach the maximum value that is allowed in any metallic crystal. That this is possible in a real material has never been shown before. (..)  the team has established ways to control the sign of the Chern number, which might bring new opportunities for exploring, and exploiting, topological phenomena. >>

Cherned up to the maximum. Paul Scherrer Institute. Jul 9, 2020.


<< Here, (AA) show that the chiral crystal palladium gallium (PdGa) displays multifold band crossings, which are connected by exactly four surface Fermi arcs, thus proving that they carry the maximal Chern number magnitude of 4. By comparing two enantiomers, (They) observe a reversal of their Fermi-arc velocities, which demonstrates that the handedness of chiral crystals can be used to control the sign of their Chern numbers. >>

Niels B. M. Schroter, Samuel Stolz, et al. Observation and control of maximal Chern numbers in a chiral topological semimetal.  Science. Vol. 369, Issue 6500, pp. 179-183. doi: 10.1126/ science.aaz3480. Jul 10, 2020.


Also

D.J. Thouless, F. D.M. Haldane, J. M.Kosterlitz  << opened the door on an unknown world where matter can assume strange states. >> Oct 4, 2016




giovedì 16 luglio 2020

# life: perform very large flights without flapping (among Andean condors)

<< Andean condors, at 10kg or more, are among the world’s heaviest flying birds. Once birds get this big, the energetic costs of flapping are so high they instead rely on currents of rising air to travel long distances. >>

AA << results showed that on average, condors fly for three hours a day, but they flap for less than two minutes of this - just 1% of their flight time. One bird even flew for more than five hours without a single flap, covering 172km. Surprisingly, the amount they flapped hardly changed whether they were in the Andes or the steppe, or whether it was windy or not. >>

<< Nonetheless, even in weak thermal conditions, which may occur in winter, (their) results suggest condors may flap for only around two seconds per km. This remarkably low investment in flapping flight is on a par with albatrosses. In fact, albatrosses appear to flap more than condors – between (1% and 15% of their flight time outside take-off) >>

<< What is particularly striking about our findings is that all the birds we studied were immature. There was some suggestion that flight performance improved with age, but the demonstration that all birds flap so rarely shows that it is possible for even young condors to invest little energy in flying. >>

Emily Shepard. We tagged Andean condors to find out how huge birds fly without flapping. Jul 13, 2020. 


H. J. Williams, E. L. C. Shepard, et al
 Physical limits of flight performance in the heaviest soaring bird.  PNAS. doi: 10.1073/ pnas.1907360117. Jul 13, 2020



mercoledì 15 luglio 2020

# evol: iterative hacking mechanics; a large group of viruses can assemble human-virus codes to produce novel chimeric (UFO) proteins

<< Like a scene out of "Invasion of the Body Snatchers," a virus infects a host and converts it into a factory for making more copies of itself. Now researchers have shown that a large group of viruses, including the influenza viruses and other serious pathogens, steal genetic signals from their hosts to expand their own genomes. >>

AA << looked at a large group of viruses known as segmented negative-strand RNA viruses (sNSVs), which include widespread and serious pathogens of humans, domesticated animals and plants, including the influenza viruses and Lassa virus (..) by stealing genetic signals from their hosts, viruses can produce a wealth of previously undetected proteins. The researchers labeled them as UFO (Upstream Frankenstein Open reading frame) proteins, as they are encoded by stitching together the host and viral sequences. There was no knowledge of the existence of these kinds of proteins prior to this study. >>

Viruses can steal our genetic code to create new human-virus genes. The Mount Sinai Hospital. Jun 18, 2020.


Jessica Sook Yuin Ho, Matthew Angel, et al. Hybrid Gene Origination Creates Human-Virus Chimeric Proteins during Infection. Cell. Vol 181, Issue 7, P1502-1517.e23. doi: 10.1016/ j.cell.2020.05.035. June 25, 2020. 



venerdì 10 luglio 2020

# gst: the physics of squeezing; how to squeeze out (quantum) noise

<< 'Squeezing' is used in physics, among other things, to improve the resolution of measuring instruments. It allows disturbing noise to be suppressed in a way that smaller signals can be detected more sensitively. (..) (AA) has now been able to show how such a squeezed state can be measured in a much simpler way than with the existing methods. Moreover, the new method allows examining squeezed states in systems where such measurements were not possible before. >> [1]

<< In the experiment (..) the thermal fluctuations of a vibrating nanomechanical string resonator are squeezed. The nanostring can be thought of as a tiny guitar string, a thousand times thinner and shorter than a human hair. (..)  If the string is deflected far enough, it ceases to behave linearly. This means that the force that deflects the string is no longer proportional to the force that pulls it back to its original position. The strong drive alters the thermal fluctuations as a result of a violation of the time reversal symmetry. In phase space, they no longer look like a circle but like an ellipse: At least in one direction, its diameter, i.e. the noise, becomes significantly smaller—it is squeezed. >> [1]

<< Quantum squeezing was a theory that was first proposed in the 1980s, the general idea being that quantum vacuum noise can be represented as a sphere of uncertainty along two main axes: phase and amplitude. If this sphere were squeezed, like a stress ball, in a way that constricted the sphere along the amplitude axis, this would in effect shrink the uncertainty in the amplitude state of a vacuum (the squeezed part of the stress ball), while increasing the uncertainty in the phase state (stress ball's displaced, distended portion). Since it is predominantly the phase uncertainty that contributes noise to LIGO, shrinking it could make the detector more sensitive to astrophysical signals. (..) The heart of the squeezer is an optical parametric oscillator, or OPO — a bowtie-shaped device that holds a small crystal within a configuration of mirrors. When the researchers direct a laser beam to the crystal, the crystal's atoms facilitate interactions between the laser and the quantum vacuum in a way that rearranges their properties of phase versus amplitude, creating a new, "squeezed" vacuum that then continues down each of the detector's arm as it normally would. This squeezed vacuum has smaller phase fluctuations than an ordinary vacuum, allowing scientists to better detect gravitational waves. >> [2]

[1] - Measure squeezing in a novel way. University of Konstanz. Jun 25, 2020.   https://phys.org/news/2020-06-measure-squeezing-in-a-novel.html
J. S. Huber, G. Rastelli, et al. Spectral Evidence of Squeezing of a Weakly Damped Driven Nanomechanical Mode.  Phys. Rev. X 10, 021066 – Jun 23,  2020.   https://journals.aps.org/prx/abstract/10.1103/PhysRevX.10.021066 

[2] - Jennifer Chu. New instrument extends LIGO’s reach. Technology "squeezes" out quantum noise so more gravitational wave signals can be detected. MIT. Dec 5, 2019.   https://news.mit.edu/2019/ligo-reach-quantum-noise-wave-1205





giovedì 9 luglio 2020

# life: the transient floating entities suspended in the skies of Venus

<< From afar, Venus seems like the most uninhabitable planet of all. >>

<< NASA’s Magellan mission conducted radar mapping of the entire surface of Venus, penetrating its cloud layer and enabling (..) to reconstruct the first 3D map of the Venusian surface. >>

<< Beneath its carbon dioxide/nitrogen atmosphere, 90 times thicker than Earth’s, a hellscape of a surface awaits. >>

<< Although (..) successfully sent numerous landers, they’ve all failed after mere hours. The reason? A layer of sulfuric acid clouds enshrouds Venus at high altitudes. These radiation-reflecting clouds create a runaway greenhouse effect: responsible for Venus’s incredible temperatures. >>

<< At 60 kilometers (36 miles) in altitude, temperatures and atmospheric pressures are similar to Earth’s. The right ingredients for life, including carbon, oxygen, and nitrogen-rich molecules, are all abundant. Ultraviolet photos of Venus display "dark patches," which Harold Morowitz and Carl Sagan suggested could indicate microorganisms. >>

<< Above the cloud-tops, Venus has been called a "paradise planet." >>

Ethan Siegel. Yes, There Really Could Be Life In The Cloud Tops Of Venus. Jul 6, 2020. 






martedì 7 luglio 2020

# gst: 'transcriptional burst frequency' modulation (more or less noise) during gene regulation

<< In cells, genes are expressed through transcription, a process where genetic information encoded in DNA is copied into messenger RNA (mRNA). The mRNA is then translated to make protein molecules, the workhorses of cells. This entire process is subject to bursts of natural stochasticity—or randomness—which can impact the outcome of biological processes that proteins carry out. >>

<< This work for the first time identifies the role of randomness in altering the outcome of a developmental process.>> Madhav Mani. 

<< By analyzing experimental perturbations of Drosophila's senseless gene against mathematical models, the team determined the sources of the gene's stochasticity, and found that the randomness appears to be leveraged in order to accurately determine sensory neuron fates. >>

<< Let's say you are quickly flipping a light switch on and off, but you want more brightness out of your bulb. You could either get a brighter bulb that produced more photons per unit time, or you could leave the switch 'on' more than 'off,' (..) What we found is that organisms control the amount of gene expression by regulating how often the gene is permitted to switch on, rather than making more mRNAs when it is on. >> Madhav Mani. 

<< From these studies, we are learning rules for how genes can be made more or less noisy, (..) Sometimes cells want to harness the genetic noise—the level of variation in gene expression—to make randomized decisions. Other times cells want to suppress the noise because it makes cells too variable for the good of the organism. Intrinsic features of a gene can imbue them with more or less noise. >> Richard Carthew. 

Alex Gerage. Toward principles of gene regulation in multicellular systems. Northwestern University. Jul 1, 2020.


Rachael Bakker, Madhav Mani, Richard W Carthew. The Wg and Dpp morphogens regulate gene expression by modulating the frequency of transcriptional bursts. eLife. doi: 10.7554/eLife.56076. Jun 22, 2020. 



venerdì 3 luglio 2020

# gst: contactless manipulation of droplets levitating in an acoustic wave

<< A unique, versatile, and material-independent approach to manipulate contactlessly and merge two chemically distinct droplets suspended in an acoustic levitator is reported. Large-amplitude axial oscillations are induced in the top droplet by low-frequency amplitude modulation of the ultrasonic carrier wave, which causes the top sample to merge with the sample in the pressure minimum below. The levitator is enclosed within a pressure-compatible process chamber to enable control of the environmental conditions. The merging technique permits precise control of the substances affecting the chemical reactions, the sample temperature, the volumes of the liquid reactants down to the picoliter range, and the mixing locations in space and time. >>

Stephen J. Brotton, Ralf I. Kaiser. 
Controlled Chemistry via Contactless Manipulation and Merging of Droplets in an Acoustic Levitator. Anal. Chem. 2020, 92, 12, 8371–8377. doi: 10.1021/ acs.analchem.0c00929. Jun 1, 2020. 


Levitating droplets allow scientists to perform 'touchless' chemical reactions.  American Chemical Society. Jun 24, 2020.



mercoledì 1 luglio 2020

# life: apropos of transitional blennies

<< Research on blennies, a family of fish that have repeatedly left the sea for land, suggests that being a 'jack of all trades' allows species to make the dramatic transition onto land but adapting into a 'master of one' allows them to stay there. >>

<< a flexible diet and behavior were likely to be instrumental in the transition to land. However, once out of the water, restrictions on the type of food available triggered major evolutionary changes, particularly to their teeth, as land dwelling blennies have become specialists in scraping algae and detritus from rocks. >>

<< having a broad diet or being behaviorally flexible can help you move into a new habitat. But once there, this flexibility becomes eroded by natural selection. This presumably means those highly specialized species are less likely to be able to make further transitions, or cope with abrupt environment changes in their existing habitat. >> Terry Ord.

How fish got onto land, and stayed there. British Ecological Society. Jun 17, 2020.  


Terry J. Ord, Peter J. Hundt. Crossing extreme habitat boundaries: Jack‐of‐all‐trades facilitates invasion but is eroded by adaptation to a master‐of‐one. Funct Ecol. doi: 10.1111/ 1365-2435.13600. Jun 16, 2020.


Also

The multifactorial relationship system evolved in Blenny. FonT. Jun 2, 2017.