# 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. 

https://www.forbes.com/sites/startswithabang/2020/07/06/yes-there-really-could-be-life-in-the-cloud-tops-of-venus/   

Also: Magellan Mission to Venus

https://nssdc.gsfc.nasa.gov/planetary/magellan.html

# 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.

https://phys.org/news/2020-07-principles-gene-multicellular.html

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. 

https://elifesciences.org/articles/56076

# 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. 

https://pubs.acs.org/doi/10.1021/acs.analchem.0c00929#

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

https://phys.org/news/2020-06-levitating-droplets-scientists-touchless-chemical.html  

# 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.  

https://phys.org/news/2020-06-fish.html

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.

https://besjournals.onlinelibrary.wiley.com/doi/10.1111/1365-2435.13600

Also

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

https://flashontrack.blogspot.com/2017/06/s-behav-multifactorial-relationship.html

# gst: elastic instabilities, a morphing model to quickly trap anything (in 100msec), the Venus flytrap (Dionaea muscipula)

<< The Venus flytrap (Dionaea muscipula) takes only 100 milliseconds to trap its prey. Once their leaves, which have been transformed into snap traps, have closed, insects can no longer escape. >>

<< the trap of the carnivorous plant is under mechanical prestress. In addition, its three tissue layers of each lobe have to deform according to a special pattern. >>

<< In order to close correctly, the traps also had to consist of three layers of tissue: an inner which constricts, an outer which expands, and a neutral middle layer. >>

Albert Ludwigs. Biomechanical analyses and computer simulations reveal the Venus flytrap snapping mechanisms. University of Freiburg. Jun 23, 2020.

https://phys.org/news/2020-06-biomechanical-analyses-simulations-reveal-venus.html

Renate Sachse, Anna Westermeier, et al. Snapping mechanics of the Venus flytrap (Dionaea muscipula). PNAS. doi: 10.1073/ pnas.2002707117. Jun 22, 2020. 

https://www.pnas.org/content/early/2020/06/19/2002707117

Also

Dionaea muscipula, with precision. FonT. Feb 2, 2016. 

https://flashontrack.blogspot.com/2016/02/rmx-s-phyto-dionaea-muscipula-with.html

# gst: self-assembly in complex patterns during the evaporation of a sessile droplet

<< When a sessile droplet containing a solute in a volatile solvent evaporates, flow in the droplet can transport and assemble solute particles into complex patterns. >>

Bryan A. Nerger, P.-T. Brun, Celeste M. Nelson. Marangoni flows drive the alignment of fibrillar cell-laden hydrogels. Science Advances. Vol. 6, no. 24, eaaz7748. doi: 10.1126/ sciadv.aaz7748. Jun 12, 2020.

https://advances.sciencemag.org/content/6/24/eaaz7748   

Thamarasee Jeewandara. Marangoni flows drive the alignment of fibrillar cell-laden hydrogels. Phys.org. Jun 25, 2020

https://phys.org/news/2020-06-marangoni-alignment-fibrillar-cell-laden-hydrogels.html

Also

keyword 'Marangoni effect'

https://en.m.wikipedia.org/wiki/Marangoni_effect

http://web.mit.edu/2.21/www/Lec-notes/Surfacetension/Lecture4.pdf

# life: a paradigm shift; extinction vs. evanescence, relict species, ...

<< The first "complete" paradigm of extinction was proposed as "the multigenerational, attritional loss of reproductive fitness," for which MALF is a suitable acronym. A "complete" paradigm must encompass cause, effect, and a mechanism. The primary goal of this study is to verify the new paradigm. (AA) cite four independent tests of the paradigm employing observational, experimental, and wholly theoretical techniques, >>

<< "extinction" presents certain problems with adjectival and gerund forms. (AA) do not refer to a process of "extinctioning" or "extincting" and there is no disciplinary field named "extinctionary" biology, ecology, or genetics. There are several possible verbs for extinction that treat the population or species as agent. These include "devolve," "senesce," "die off," "terminate," and "disappear," among others. However, all of these are in common use with connotations that would distract from (they) proposed meaning. "Devolve" is common in antievolutionist literature. "Senesce" is usually applied only to individuals. "Die off" does not have a single-word noun form. "Terminate" used intransitively comes close to our proposed meaning, but the popularity of the Arnold Schwarzenegger film Terminator will suggest the transitive form to most people. "Disappear" suggests something that is merely out of sight, not necessarily extinct. Instead of these common words, (they) propose using a verb with no distracting connotations. (AA) take our cue from Jefferson’s concern over extinction. Jefferson (1799:256) uses the term "evanish," or in its modern form, "vanish." The adjectival form "vanished" is usable but the noun form sounds a bit awkward: "vanishment." However, Jefferson’s "evanish" calls attention to the Latin root, e + vanescere = to pass away. "Evanesce" has an elegant noun form, "evanescence," and several adjectival forms covering a range of states: "evanesced" denoting the completed action, "evanescing" denoting an action in process, and "evanescent" denoting action in process or in potential. In physics, the adjective "evanescent" is used to designate an electromagnetic field that does not propagate waves beyond the vicinity of the source of the field. Physics and biology are sufficiently distinct that (AA) proposed usage would not create confusion. "Evanescence" does not imply an external agent performing the action and fits the understanding of extinction as a process without adding confusing connotations. This process may be a precursor or complement to evolution, but not necessarily so. >>

Delbert Wiens, Timothy Sweet, Thomas Worsley. Validating the New Paradigm for Extinction: Overcoming 200 Years of Historical Neglect, Philosophical Misconception, and Inadequate Language. The Quarterly Review of Biology. Vol. 95, Issue 2, Pages 109-124. doi: 10.1086/709086. Jun 2020.

https://www.journals.uchicago.edu/doi/10.1086/709086   

Goodbye 'extinction,' hello 'evanescence'? Validating a new paradigm. University of Chicago. Jun 18, 2020. 

https://phys.org/news/2020-06-goodbye-extinction-evanescence-validating-paradigm.html