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Tuesday, May 5, 2015

Survival of the sickest‬ - Sharon Moalem - Review

Running into 8 chapters, the first 3 were very attractive. This should make a good reading both for the beginners and non-science readers. Written in a very simple language the book lacks references or foot notes then and there. A few notes are given at the end of the book, but if that was provided in-situ, the readability would have been enhanced.
Some chapters in the end describe what we call "junk science". The junk science is the 'projected-out' views during the course of a research and at times it would mark serendipity as well. Those events that come in the 'context' of a topic cannot be taken to describe the whole. For instance, diabetes that describes increased incidence of sugar in a human is marked 'favourable' for persons living in cold regions for obvious reasons. A person in cold regions needs to burn more sugar to keep himself warm. But this cannot be substituted as 'evolution' phenomenon in the present context where many in tropical region have acquired this as a result of life-style.
Likewise, the author predicts flaw in evolution, which is not agreeable scientifically. The Evolution theory is still debatable and science has not concretely proved it. That warrants no discussion on a topic related to it. The author attributes 'gender' based on evolution and not on more obvious reasons like 'natural selection' and hormones.
On microbes, the writings are interesting, but I felt a negative approach in describing their existance and functionality. Here is what one can summarize on the book:
Ch.1. Ironing it out
Hemochromatosis is an inherited disease in which the body continues to load up on iron because the mechanism regulating iron has broken down. The suggestion is that natural selection is maintaining this genetic defect because it had conferred some benefit in the past.
The long held tradition of bloodletting to fight disease may therefore have had a good basis in fact after all. Starving infectious bacteria of iron by reducing the amount of blood is the surprising benefit that might explain why people believed in the value of bloodletting for so long.
Ch. 2. A spoonful of sugar helps the temperature go down
Diabetes is a disease where the body fails to remove excess sugar from the bloodstream. Dr. Moalem suggests that excess sugar in the blood could have been selected for in the past because sugar could act like antifreeze in times of extreme cold. Now this is not justifiable in the present day scenario.
Ch. 3. The cholesterol also rises
This chapter mentions about Vitamin D and its tremendous benefit in preventing many diseases, not just rickets. There is enough Vitamin D added to milk to prevent rickets. Those living in northern latitudes are at a disadvantage because several minutes of directly overhead sunshine is what is needed to convert cholesterol in our bodies into enough Vitamin D to have an effect. Taking Vitamin D supplements is also an option, as is an ultraviolet B tanning salon or eating fatty fish as the Inuit do.
While the sun makes Vitamin D, it unfortunately destroys folic acid. Skin colour is the adaptation that balances out the effect of the sun. People with dark skin can protect themselves from folic acid depletion, but they need to carry higher amounts of cholesterol to maximize whatever sunlight gets through the skin.
Surprisingly the author asks us to avoid sunglasses while sunbathing. The pituitary gland is involved in helping produce melanin, which darkens the skin. If the pituitary gland does not get signal from the optic nerve (while wearing sunglasses) then the body will not get the right signal about the direct sunlight.
Ch. 4. Hey, bud, can you do me a fava?
Many plants produce toxins to protect themselves from predators. People with favism cannot clear out the free radicals produced by fava beans because of a genetic deficiency. The free radicals attack red blood cells. It turns out that people with this genetic deficiency end up being more resistant to malaria. Does not sound well with the present day scenario on this disease.
Ch. 5. Of microbes and men
The rod of Asclepius — a symbol depicting removal of the Guinea worm parasite is mentioned here. The chapter makes an interesting reading with microbes such as T.Gondii in cats, D. dentriticum in sheep, H. argyraphaga in spider and common sneezing virus bringing out some spine chilling facts. This section has no references for all the incidents mentioned.
Ch. 6. Jump into the gene pool
Large portions of our junk DNA (DNA that does not code for proteins) are made of jumping genes. Empty space? Retroviruses are made of RNA, and can be written into DNA. HIV is a retrovirus, and the drug “cocktail” therapy used to combat HIV
is aimed at stopping the enzyme that helps the retroviruses become part of DNA.
Ch. 7. Methyl madness : road to the final phenotype
Epigenetics is a whole new field in genetics that is concerned with the study of how children can inherit and express new traits derived from their parents without changes in the underlying DNA. This chapter has more of author's views than science and hence one can lose interest given the way exaggerations are made out of the mutations and telomers.
Ch. 8. That’s life : why you and your iPod must die
Again I would disagree with the author on the theory that is put forth in this chapter. That every cell is programmed for a certain number of multiplications (Hayflack limit) and hence death should come only when this limit is reached, does not hold good in a 'thermodynamic' world where everything is dependent on one's life style, environment and food. That would mean every person should live at least 60 years compulsorily!
Points in favour of the aquatic ape theory that are not strong enough:
– humans are the only land animals with fat attached to our skin (like hippos, sea lions, and whales)
– the ability to survive in both land and water environments has tremendous survival benefits against predators
– walking upright helps in venturing into deeper water and so this is how bipedalism may have come about
– we may have lost our fur so as to become more streamlined in the water
– we have downward-facing nostrils, which allowed us to dive
– the extra fat in babies help keeps them afloat
– newborns don’t start breathing until they feel air on their face, which makes birthing in water very safe, and actually easier on
the mother
– newborns reflexively hold their breath, but they also make rhythmic movements that propel them through the water (a behaviour which lasts about four months)–this makes more sense in the aquatic ape theory than in the Savannah theory

Friday, March 13, 2015

How chameleons change their colour?

With a little help from Raman spectroscopy, Swiss scientists have found the answer to an endlessly intriguing evolutionary poser. 

It turns out that chameleons have a mobile “lattice” of#nanocrystals on the surface of their skin, which come together, change shape and disperse thereby shifting the wavelength of light reflected by the reptile.

Scientists studied the panther chameleon Furcifer pardalis from Madagascar, known for its particularly dynamic colour changing abilities — going from green to red within minutes — especially during social interactions such as courtship or male-male combat. These #nanocrystals — of different shapes, sizes and organizations — are distributed in two layers of skin cells called #iridophores (iridescent light-reflecting cells). While the upper layer of iridophores is responsible for rapid colour change achieved by a shift in spacing of nanocrystals in a triangular lattice, the deeper layer of cells broadly reflects light, especially in the near-infrared range, the scientists report in Nature Communications.

The distance between crystals is on average 30 per cent less in the resting state (blue or green skin) than it is in the excited state (yellow or white). With an increase in distance between nanocrystals in excited male panther chameleons, iridophores shift their selective reflectivity from short (blue) to long (red or infrared) wavelengths, causing the corresponding shift from green to yellow/orange skin, says the paper.

Chameleons originated in post-Gondwanan Africa around 90 million years ago. The way these iridophores are organised allows some species “to combine efficient camouflage with spectacular display,” while also potentially providing passive thermal protection.

Read more about this here:

‪‎Physics of the Impossible by Michio Kaku - ‪Review

The "impossibilities" in Physical Life have been narrated well with skirmishing incidents of the Bohr-Einstein-Schrodinger era debates that are found written in many books. But Michio Kaku takes the reader beautifully into some impossibilities predicted by Physics which could become possible in the years to come (I am yet to read his book "Physics of the Future"). Occasionally a few pages are very
interesting, nevertheless, the reader is never distracted. Quotes from Bohr, Pauli, Sagan and others are very interesting. The analysis about symmetry on which physics is now based and the nature's laws connected with predators and preys are very reasonable. The prey is always faster than the predator!
A few classifications are significant:
"Class 1 Impossibilities: These are technologies that are impossible today but that do not violate the known laws of physics. So they might be possible in this century, or perhaps the next. They include teleportation, anti-matter engines, certain forms of telepathy, psycho kinesis, and invisibility.
“Class 2 Impossibilities: These are technologies that sit at the very edge of our understanding of the physical world. If they are possible at all, they might be realized on a scale of millennia to millions of years. They include time machines, the possibility of hyperspace travel, and travel through wormholes.”
“Class 3 impossibilities: These are technologies that violate the known laws of
physics. Surprisingly, there are vary few such technologies. If they do turn
out to be possible they would represent a fundamental shift in our understanding of physics.”
And the Civilizations that would bother these:
Type 1 civilization: Those that harvest planetary power, utilizing all the sunlight that strikes their planet. They can, perhaps, harness the power of volcanoes, manipulate the weather, control earthquakes, and build cities on the oceans. All planetary power is with in their control.
Type 2 civilization: Those that can utilize the total power of their sun, making them 10 billion times more powerful then a type 1 civilization. A type 2 civilization in a sense, is immortal; nothing known to science, such as ice ages, meteor impacts, or even supernovae, can destroy it.
Type 3 civilization: Those that can utilize the power of an entire galaxy. They are 10 billion times more powerful then a type 2 civilization. The Borg in Star Trek, the Empire in Star Wars, and the galactic civilization in Asimov’s Foundation series correspond to a type 3 civilization. They have colonized entire star systems and can exploit the black hole at the center of their galaxy. They freely roam the galaxy.
This apart, his views on Ramjet, Telepathy, Force Fields,Invisibility, Energy Weapons, Teleportation, Psychokinesis, Robots, UFOs & Aliens,Space Travel (including Faster Than Light travel & Particle) Parallel & Alternate Universes, Time Travel, Perpetual Motion Machines, Precognition, Parallel Universe and perpetual motion, make the book very interesting one.
The ‪#‎Quantum‬ era incidents including the Dirac's ignorance to patent his equation on ‪#‎Relativity‬ theory, because of which gadgets exist in our hands, truly refresh our sense of inclination towards Physics, in particular and Science, in general.
That the entire Universe/Multiverse has dark energy to about 73%, with the energy by humans amounting to only about 0.03% is truly astonishing (while computing zero point energy) and shows the long way one has to cover to understand the Creator.