lunedì 31 luglio 2017

# s-ecol: asymmetric cooperation during symbiosis (among Polynucleobacteria)

<< Relationships where two organisms depend on each other, known as symbiosis, evoke images of partnership and cooperation. But a new study in Nature Ecology and Evolution shows that, when it comes to certain microorganisms, symbiotic partners are actually being held "hostage" >>

Hostage situation or harmony? Researchers rethink symbiosis. July 27, 2017

Vittorio Boscaro, Martin Kolisko, et al.  Parallel genome reduction in symbionts descended from closely related free-living bacteria. Nature Ecology & Evolution 1, 1160–1167 (2017) doi: 10.1038/s41559-017-0237-0 Publ. July 21,  2017

giovedì 27 luglio 2017

# s-game: equilibrium, a chimeric target

<< In 1950, John Nash — the mathematician later featured in the book and film “A Beautiful Mind” — wrote a two-page paper that transformed the theory of economics. His crucial, yet utterly simple, idea was that any competitive game has a notion of equilibrium: a collection of strategies, one for each player, such that no player can win more by unilaterally switching to a different strategy >>

<< Nash’s equilibrium concept, which earned him a Nobel Prize in economics in 1994, offers a unified framework for understanding strategic behavior not only in economics but also in psychology, evolutionary biology and a host of other fields. Its influence on economic theory “is comparable to that of the discovery of the DNA double helix in the biological sciences,” wrote Roger Myerson of the University of Chicago, another economics Nobelist >>

In a paper posted online last September AA << proved that no method of adapting strategies in response to previous games — no matter how commonsensical, creative or clever — will converge efficiently to even an approximate Nash equilibrium for every possible game. It’s “a very sweeping negative result,” Roughgarden (Tim Roughgarden) said >>

Erica Klarreich. In Game Theory, No Clear Path to Equilibrium. July 18, 2017.

Yakov Babichenko, Aviad Rubinstein. Communication complexity of approximate Nash equilibria. arXiv:1608.06580 Sep. 13,  2016

mercoledì 26 luglio 2017

# s-pnei: brain-like activities; syntesis and release of dopamine by T-cells

<< a proportion of human TFH  [follicular helper T] cells contain dense-core granules marked by chromogranin B, which are normally found in neuronal presynaptic terminals storing catecholamines such as dopamine.  TFH cells produce high amounts of dopamine and release it upon cognate interaction with B cells >>

<< faster dopamine-induced T–B-cell interactions increase total germinal centre output and accelerate it by days >>

Ilenia Papa, David Saliba, et al. TFH-derived dopamine accelerates productive synapses in germinal centres. Nature 547, 318–323 (July 20, 2017) doi: 10.1038/nature23013

Kate Prestt. Discovery of brain-like activity in immune system promises better disease treatments. July 13, 2017

martedì 25 luglio 2017

# s-astro: a macro "switch-like" dynamics

AA << propose  that  a  “switch-like”  magnetosphere  exists  at Uranus  in  both  equinox  and  solstice  seasons,  where  the  planetary rotation  drives  the  interchange  between  an  open  magnetosphere  and  a closed  magnetosphere  each  Uranus  day >>

Xin Cao , Carol Paty. Diurnal  and  seasonal  variability  of  Uranus's magnetosphere. Journal  of  Geophysical  Research:  Space  Physics. Vol. 122,  Issue  6, June  2017 Pages  6318–6331 Publ. June 27, 2017 doi:  10.1002/2017JA024063

<< Stay weird, Uranus. We wouldn’t have you any other way >>

Rae Paoletta. Uranus Is Even Freakier Than We Thought. June 23, 2017.

lunedì 24 luglio 2017

# s-chem: self-assembled also into cuboids

<< Phospholipid liposomes are archetypical self-assembled structures. To minimize the surface tension, the vesicles typically are spherical >>

<< A 1,2-diamidophospholipid is presented that self-assembles into a cuboid structure. Owing to intermolecular hydrogen bonding, the bilayer membranes form an exceptionally tight subgel packing, leading to a maximization of flat structural elements and a minimization of any edges. These conditions are optimized in the geometrical structure of a cube >>

Frederik  Neuhaus, Dennis  Mueller, et al. Vesicle  Origami:  Cuboid  Phospholipid  Vesicles  Formed  by Template-Free  Self-Assembly. Angewandte  Chemie  International  Edition.  Vol. 56,  Issue 23, June  1,  2017. Pages  6515–6518. doi: 10.1002/anie.201701634

Phosphorus-containing lipid  molecule self-assembles into a cuboid structure. June  5,  2017

venerdì 21 luglio 2017

# s-astro: the “mudball” model; a terrestrial muddiness from carbonaceous asteroids

<< Scientists have long held the belief that planets – including Earth – were built from rocky asteroids, but new research challenges that view >>

Planets like earth may have had muddy origins. July 14, 2017

<< It would have been a mud, rather than a rock >>

Philip A. Bland, Bryan J. Travis. Giant convecting mud balls of the early solar system. Science  Advances 14 Jul 2017: Vol.  3,  no.  7,  e1602514 doi: 10.1126/sciadv.1602514

giovedì 20 luglio 2017

# s-lang: jazz session during a bird song

<< Music is thought to engage its listeners by driving feelings of surprise, tension, and relief through a dynamic mixture of predictable and unpredictable patterns, a property summarized (..) [by AA] as "expressiveness" >>

<< birds render their songs more expressive by subtly modifying note timing patterns, similar to musical operations like accelerando or ritardando >>

AA << findings bear consequences for neuronal models of vocal sequence generation in birds, as they require non-local rules to generate rhythm >>

Tina C Roeske, Damian Kelty-Stephen, Sebastian Wallot. Birds have swing: Multifractal analysis reveals expressive rhythm in birdsong. BioRxiv June 29, 2017 doi: 10.1101/157594

<< A veery thrush, ready to join the band >>

Michael Le Page. Swinging birds play with rhythm like jazz musicians. July 14, 2017

Lang Elliott. Veery Thrush. June 1, 2010

mercoledì 19 luglio 2017

# s-chem: self-assembling 'origami' nanoscale architectures by DNA staple strands

<< DNA origami is a technique that uses hundreds of short DNA oligonucleotides, called staple strands, to fold a long single-stranded DNA, which is called a scaffold strand, into various designer nanoscale architectures >>

Hong F, Zhang F, et al. DNA Origami: Scaffolds for Creating Higher Order Structures. Chem Rev. 2017 Jun 12. doi: 10.1021/acs.chemrev.6b00825.

martedì 18 luglio 2017

# s-behav: disruptive colouration to gain cryptic benefits (among the reef fish Dascyllus aruanus)

<< Animals use disruptive colouration to prevent detection or recognition by potential predators or prey. Highly contrasting elements within colour patterns, including vertical or horizontal bars, are thought to be effective at distracting attention away from body form and reducing detection likelihood. >>

AA << results provide evidence that fish camouflage is more complex than it initially appears, with likely many factors influencing the detection likelihood of prey by relevant predators >>

Phillips GAC, How MJ, et al. Disruptive colouration in reef fish: does matching the background reduce predation risk?  J Exp Biol. 2017 Jun 1;220 (Pt 11): 1962-1974 doi: 10.1242/jeb.151480

lunedì 17 luglio 2017

# s-gene: epigenetics, more than just genes

<< We are more than the sum of our genes. Epigenetic mechanisms modulated by environmental cues such as diet, disease or lifestyle take a (..) role in regulating the DNA by switching genes on and off >>

AA << focused on a particular modification called H3K27me3 that can also be found in humans >>

Max Planck Society. Epigenetics between the generations: Researchers prove that we inherit more than just genes. July 14, 2017

Fides Zenk, Eva Loeser, et al. Germ line–inherited H3K27me3 restricts enhancer function during maternal-to-zygotic transition. Science  14 Jul 2017: Vol. 357, Issue 6347, pp. 212-216 doi: 10.1126/science.aam5339

sabato 15 luglio 2017

# s-behav: mafia-style among Cuckoos (the brown-headed cowbird Molothrus ater)

<< Why do many hosts accept costly avian brood parasitism even when parasitic eggs and nestlings differ dramatically in appearance from their own? Scientists argue that evolutionary lag or equilibrium can explain this evolutionary enigma. Few, however, consider the potential of parasitic birds to enforce acceptance by destroying eggs or nestlings of hosts that eject parasitic eggs and thereby reject parasitism.  This retaliatory “mafia” behavior has been reported in one species of parasitic cuckoo but never in parasitic cowbirds. >>

AA << present experimental evidence of mafia behavior in the brown-headed cowbird (Molothrus ater ) >>

Jeffrey P. Hoover, Scott K. Robinson. Retaliatory mafia behavior by a parasitic cowbird favors host acceptance of parasitic eggs. PNAS 2007 vol. 104 no. 11: 4479–4483  doi: 10.1073/pnas.0609710104

Andy Coghlan. Cuckoos use mafia-style tactics to raise young.  March 5, 2007

Brown-headed cowbird

venerdì 14 luglio 2017

# e-tech: store data with CRISPR–Cas tech.; biologists have now joined the party

<< Internet users have a variety of format options in which to store their movies, and biologists have now joined the party. Researchers have used the microbial immune system CRISPR–Cas to encode a movie into the genome of the bacterium Escherichia coli. >>

<< “Cells have this privileged access to all sorts of information,” he [Seth Shipman] says. “I would like to have these molecular recordings functioning in the developing nervous system and recording information.” >>

Heidi Ledford. Lights, camera, CRISPR: Biologists use gene editing to store movies in DNA. Technique demonstrated in E. coli suggests ways to record key events in a cell's life. July 12, 2017

Shipman, S. L., Nivala, J., et al. Nature doi: 10.1038/nature23017 (2017).


2073 - a few hints of our presence. Oct 13, 2006.

giovedì 13 luglio 2017

# s-brain: neuro-active areas during the real-time creation of funny stories

<< Unlike passive humor appreciation, the neural correlates of real-time humor creation have been unexplored. >> [!]

<< Greater comedic experience was associated with decreased activation in the striatum and medial prefrontal cortex (mPFC), but increased activation in temporal association regions (TMP).  Less experienced comedians manifested greater activation of mPFC, reflecting their deliberate search through TMP association space. Professionals, by contrast, tend to reap the fruits of their spontaneous associations with reduced reliance on top-down guided search. >>

Ori Amir, Irving Biederman. The Neural Correlates of Humor Creativity. Front. Hum. Neurosci., 25 Nov. 25, 2016 doi: 10.3389/fnhum.2016.00597.

Michelle Boston. Researchers pinpoint the regions of the brain that spark during the telling of a funny story. Feb. 27, 2017.

mercoledì 12 luglio 2017

# s-phys: more about retrocausality

<<  In a new paper (..) [AA] have lent new theoretical support for the argument that, if certain reasonable-sounding assumptions are made, then quantum theory must be retrocausal >>

<< retrocausality means that, when an experimenter chooses the measurement setting with which to measure a particle, that decision can influence the properties of that particle (or another particle) in the past, even before the experimenter made their choice. In other words, a decision made in the present can influence something in the past >>

<< "Speculatively, if there is retrocausality in the universe, then it might be the case that there are certain eras, perhaps near the big bang, in which there is not a definite arrow of causality. You might imagine that a signature of such an era might show up in cosmological data, such as the cosmic microwave background. However, this is very speculative, and I have no idea what signatures we might expect yet." >> Matthew S. Leifer.

<< The physicists don't have any experiments lined up to test retrocausality—but as the idea is more an interpretation of observations rather than making new observations, what's needed most may not be a test but more theoretical support >>

Lisa Zyga. Pysicists provide support for retrocausal quantum theory, in which the future influences the past. July 5,  2017.

Matthew S. Leifer,  Matthew F. Pusey. Is a time symmetric interpretation of quantum theory possible without retrocausality?   Proc. Royal Soc. A. June  2017 Volume 473,  issue 2202 doi: 10.1098/rspa.2016.0607 Publ. Jun. 21, 2017.

martedì 11 luglio 2017

# s-astro: the sonic multiverse, by Gavin Starks

<< A project that explores whether there is a musical equivalent to the curvature of spacetime will be presented on Thursday 6 July by Gavin Starks at the National Astronomy Meeting at the University of Hull >>

AA << aim is to test whether mathematical relationships that describe cosmology and quantum mechanics can be applied to a sonic universe , or 'soniverse' >>

Royal Astronomical Society. Adventures in acoustic cosmology. July 6, 2017

Gavin Starks. Escape into the multiverse. Jan. 27, 2017

lunedì 10 luglio 2017

# s-behav: mimic the sound of musk hogs to avoid being eaten

<< Bird or beast? A cuckoo seems to have learned how to mimic the sounds made by the pig-like peccaries it lives alongside, perhaps to ward off predators >>

Sandrine Ceurstemont. Cuckoos mimic the sound of musk hogs to avoid being eaten. July 3, 2017.

<< Acoustic communication is particularly important in environments such as dense tropical forests, where the dim light constrains the efficacy of visual signals >>

<< In these environments, complex species interactions could promote the evolution of acoustic signals and result in intriguing patterns of mimicry and convergence >>

AA << demonstrate that the acoustic characteristics of bill clacking in ground-cuckoos are more similar to teeth clacking of peccaries than to bill clacking of the more closely related Geococcyx roadrunner >>

Fabio Raposo do Amaral, Gabriel Macedo, et al. Bluffing in the forest: Neotropical Neomorphus ground-cuckoos and peccaries in a possible case of acoustic mimicry. J Avian Biol doi: 10.1111/jav.01266. June 29, 2017

venerdì 7 luglio 2017

# e-web: sending a message without carriers

AA << by using the quantum Zeno effect and a single-photon source, direct communication without carrier particle transmission is implemented successfully >>

Yuan Cao, Yu-Huai Li, et al. Direct counterfactual communication via quantum Zeno effect. PNAS 2017 114 (19) 4920–4924

Joshua Roebke. How to Send a Message without Sending Anything at All. June 27,  2017.

giovedì 6 luglio 2017

# s-brain: to distinguish between reality and imagination

<< neurons in the part of the brain found to be abnormal in psychosis are also important in helping people distinguish between reality and imagination >>

AA << investigated how the brain codes visual information in reality versus abstract information in our working memory and how those differences are distributed across neurons in the lateral prefrontal cortex region of the brain >>

Crystal Mackay. Researchers identify specific neurons that distinguish between reality and imagination. June 1, 2017

AA << results indicate that a functionally diverse population of LPFC (lateral prefrontal cortex) neurons provides a substrate for discriminating between perceptual and mnemonic representations of visual features >>

Diego Mendoza-Halliday & Julio C. Martinez-Trujillo. Neuronal population coding of perceived and memorized visual features in the lateral prefrontal cortex. Nature Comm. 8, Article no: 15471 (2017) doi: 10.1038/ncomms15471 Publ. Jun 01,  2017

mercoledì 5 luglio 2017

# s-gst: una immagine del reale: il gomitolo "vibrazionale"

una immagine del reale: il gomitolo "vibrazionale"  (pseudo quasi- stocastico) dalle spiccate proprieta' autoassemblanti ...

<< Mitotic chromosome assembly remains a big mystery in biology >>

Ewa Piskadlo, Alexandra Tavares,  Raquel A Oliveira. Metaphase  chromosome structure is  dynamically maintained by condensin I-directed DNA (de)catenation. doi: 10.7554/eLife.26120 May 6, 2017


immagini di "gomitolo" circa ipotetici altri scenari (espressi in rime quasistocastiche):

martedì 4 luglio 2017

# s-zoo: live with stress in a salamander

<< During embryonic development, cells of the green alga Oophila amblystomatis enter cells of the salamander Ambystoma maculatum forming an endosymbiosis >>

A << two-by-two-way analysis revealed that intracellular algae exhibit hallmarks of cellular stress and undergo a striking metabolic shift from oxidative metabolism to fermentation >>

<< In stark contrast to its algal endosymbiont, the salamander cells did not exhibit major stress responses, suggesting that the host cell experience is neutral or beneficial >>

John A  Burns et al. Transcriptome  analysis illuminates the nature of  the intracellular interaction in a  vertebrate-algal symbiosis. doi: 10.7554/eLife.22054.001 May  2,  2017.

The struggle to live in a salamander. In  the symbiotic  relationship formed between algae and salamanders, only the  algae show stress. June 30, 2017

sabato 1 luglio 2017

# s-chem: more on the anomalous properties of water

<< Most of us know that water is essential for our existence on planet Earth. It is less well-known that water has many strange or anomalous properties and behaves very differently from all other liquids >>

<< Some examples are the melting point, the density, the heat capacity, and all-in-all there are more than 70 properties of water that differ from most liquids >>

<< These anomalous properties of water are a prerequisite for life as we know it >>

<< "The new remarkable property is that we find that water can exist as two different liquids at low temperatures where ice crystallization is slow" >> Anders Nilsson.

Water exists as two different liquids. June 26, 2017.

Fivos Perakisa, Katrin Amann-Winkela, et al. Diffusive dynamics during the  high-to-low density transition in amorphous ice. PNAS 2017 doi: 10.1073/pnas.1705303114.