Our Rivers.....Dammed Everywhere !

  

Amazonia -Amazon River and the drainage basin :
courtesy Wikipedia

This sums up  the state of almost all the  major rivers on Earth. Globally, dams, small and big are being built as a part of developmental agenda. However environmentalists have serious reservations. While developers  assert  with solid  numbers in terms of quantity  of water saved,  areas of farmland irrigated and gigawatts of  electricity generated,  environmentalists are often at a disadvantage because they don't have numbers to support their arguments. But it is indeed true  that  dam building exercises expose  river basins and the associated ecosystem to irreversible alterations which are often irreparable and or irremediable.  

In a recent issue of Nature Latrubesse and his team  ask and answer the crucial question: Can we  quantify  the effects of  dams on the ecosystem? They  focused on  the Amazon basin, its floodplains,  estuaries and the whole diverse ecosystem sustained by the mighty   Amazon and its tributaries. Amazonia, with its amazing biodiversity is an invaluable ecological marvel which  influences terrestrial climate. Evolved over  millions of years of geological history, Amazonian ecosystem is critical to the well being of mother Earth.   A total of 428 hydel projects (of which    roughly 140 are completed or in advanced stages of construction)  are planned along the rivers.  This means encroaching into Amazonina forests and eating into the pristine forest areas referred to as Intact Forest Landscapes(IFLs).   Hence it has become imperative that we assess the impact of dams  on  the Amazonian ecosystem but conduct similar studies  on all other major rivers.   Taking into consideration a multiplicity of  short term and long term effects Latrubusse and team calculate  Dam Environmental Vulnerability Index , abbreviated as DEVI to quantitatively assess the impact of  dams, both existing  and proposed  on the environment.  DEVI is a composite parameter which  includes Basin integrity Index, (BII), Fluvial Dynamics Index (FDI) and DII (Dam impact Index). What do each of these indices stand for? The team provides the following definitions: 

BII: Basin Integrity Index : quantifies  the vulnerability of the river basin to existing and potential changes in  land use , potential erosion and runoff pollution; 

FDI : Fluvial Dynamics Index :Gauges the influence of he fluxes of sediment transported by the rivers, the morphodynamic activity of the rivers, stage -range of the flood pulse;

DII: Dam Impact Index: quantifies how much of the river system will be affected by the planned and built dams. 

Latrubusse and coworkers feel that often the benefits of the mega hydel projects are  exaggerated  and the cost of environmental vulnerability undermined.  They and other likeminded scientists caution that indiscriminate  dam building projects could spell  recipe for sure disaster. 

TAILPIECE

Alas! The river has already been marginalised.   Web search for Amazon tosses up  links for  the online shopping giant, rather than for the river.    

References 

1. Damming the rivers of Amazon basin Latrubusse et al Nature 15 June 2017, Vol.546, pages 363-369

2. Dams in Amazonia  

3. Dams on the Amazon river could have widespread devastating impacts and we keep  building more of them   by Pierre-Louis Popular Science , June 2017

4. The Amazon basin in transition Davidson et al Nature 19 January 2012, vol. 481, pages 321-328

5. Balancing hydropower and biodiversity in the Amazon, Congo and Mekong  Windmill et al Science 8 January 2016, 128-129

The other side is getting greener

President Trump's declaration that the USA would pull out of the Paris Climate  Agreement has sent across waves of disappointment. The agreement was a collective , ambitious   commitment to to keep global warming well below 2 deg.Celsius. 

As  early as 1861 Tyndall, professor of Physics at the Royal Institute  detected how human activities could  influence atmospheric temperature. A hundred years later Manabe and colleagues  provided a rigorous   quantitative platform. Piers Forster at the School of Earth and Environment, University of Leeds,U.K  highlights the significance of Manabe’s research work. Watanabe’s group built robust models of climatic change. To quote from his website  “ Earth’s climate has fluctuated greatly during the geological past. Throughout my career, past climate changes have posed many challenging questions, which we have tried to answer using climate models with various complexity.”

Aron Putnam at the  School of Earth and Climate Sciences & Climate Change Institute University of Maine together with Wallace Broecker  faculty at the Earth & Environmental sciences at  the Columbia University  studied the rainfall pattern.  This is what they say: The first possibility is that rainfall in the tropics will increase  and  the subtropics and mid latitudes will become more arid.  A second possibility is that Earth’s thermal equator , around which the planets’s rain belts and dry zones are organised , will migrate northward. This northward shift will be a consequence of the Northern Hemisphere , with its large continental area , warming faster than the Southern Hemisphere, with its large oceanic area. A third possibility is that both of these scenarios will play out simultaneously.

Tropical zone highlighted in pink Courtesy: wikipedia  KVDP's Own work. 

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While we are busy  with models and predictions, Mother Nature is quietly at work.  Though  most of Antarctica is snow covered uninhabitable place,  of late it has been turning green with a crop of moss. Amesbury and colleagues at the University of Exeter observe that the Antarctican  ground is  getting greener for the past 50 years. It looks like  as the north gets increasingly uninhabitable, there  will be a southward human migration eventually 

REFERENCES:

 1. Tyndal,J:  On the absorption and radiation of heat by gases and vapours. Philos. Mag. 22: 169–194 and 273–285

2. Forster, P: Half a century of robust climate models  Nature 545, 296-7 (2017) 

3.Manabe & Stricker : Thermal equilibtium of the atmosphere with a convective adjustment 21, 361-385 4.Manabe & Wehterald :  Thermal equilibrium of the atmosphere with a relative distribution of humidity  J. Atmospheric sciences  1967 24(3) 241-259 

5. Putnam & Broecker Human induced changes in the distribution of rainfall Science Advances  31 May , 2017 

6. Amesbury et al  Widespread biological response to rapid warming on the Antarctic peninsula, Curr Biol, 27(11), 1616-1622

The Ghent Altarpiece: A Chemical investigation

The Ghent Altarpiece is a  huge painting that adorns the altar of St Bavo's cathedral, Ghent, Belgium. Measuring 11ft x14ft overall,  it consists of 12 foldable oak panels depicting  biblical themes.  Conceived and created by  van Eyck brothers Jan and Hubert  the work was completed in 1432.  The lower middle  panel " Adoration of the Mystic Lamb" unifies the entire work.

Renaissance artists like van Eyck brothers  the mostly used  mineral  pigments.  For example  goethite  a mixture of iron oxide-hydroxide with a sprinkle of manganese went by the name brown ochre or brown earth. Green earth was glauconite/celadonite a complex  mixed silicate of aluminium, iron, potassium and magnesium. Red ochre was hematite dehydrated iron oxide.  Yellow ochre, which is hydrated iron oxide could yield bright yellow to  orange.  For deep orange artists used orpiment,  arsenic sulphide. Ultra marine blue was the costliest colour  obtained by grinding  lapis lazuli and extracting the powder with water. Azurite was also used for blue. And for black either carbon black from soot or  peach stones charred and ground to a fine powder were used. Working with oil paints   artists might have instinctively and intuitively discovered the extra dimension glaze added to the painting. 

Ghent Altarpiece: Panels open (courtesy: wiki) 

The Ghent altarpiece  has aged through rough times. Hence it  is possible that it might  have undergone

Ghent Altarpiece: Panels closed (courtesy wiki)

several cycles of   restore/reconstruct/repair.   How to get down to the innermost layer of paint laid down originally by van  Eyck brothers almost six hundred years ago?  University of Antwerp, Royal institute for Cultural heritage, Brussels and the University of Ghent  brought their scientists together and thus began a project on  the detailed analysis of the The Ghent Altarpiece.  A recent issue of Angewandte  Chemie International edition(1) carries their probe analysis.  Dr van der Snickt, corresponding author of the paper is  with  the dept. of chemistry,  University of Antewerp, and his research area   is conservation and restoration of heritage art. Dr Snickt uses modern analytical tools which are non-invasive such as  Macroscopic X-ray fluorescence(MA-XRF), secondary electron microscopy- energy dispersive X-ray analysis(SEM-EDX), and synchrotron radiation based micro-XRF(SR-- muXRF).   These are basically chemical imaging techniques and specific to each element. In other words elements yield  their  characteristic signature pattern.   Hand-held scanning devices were used to image the entire surface. 16 billion spectra were thus collected, processed and analysed.  They also analysed the cross section of a tiny speck of paint layer by layer.   They discovered the yellow varnish layers underneath  large areas which have been overpainted. They also observed that damaged spots in the original painting have been filled out with iron containing putty like material and then painted over. Since  advent of organic dyes in 18th century pushed  out mineral colours, the team could also  get a rough idea when repair/restoration were carried out.

Tailpiece: 

The lower left panel depicting the Righteous Judges has been missing for decades. A copy created by Jef Van der Veken stands in its place.  In Albert Camus' novel The fall,  Clamence boasts that the original  is in his possession. He won't return it  because none  misses the original all are happy with the copy also because innocent lambs and righteous judges no longer exist in modern times.     

REFERENCES:

1. Large-Area Elemental Imaging Reveals Van Eyck's Original Paint Layers on the Ghent   

     Altarpiece (1432), Rescoping Its Conservation Treatment

     Geert Van der Snickt et al,  Angewandte Chemie International Edition

     Volume 56,  Issue 17, pages 4797–4801, April 18, 2017

Hydrogels -Extraordinary

Hydrogels are blobs of water entrapped in a  mesh. The mesh is a network of hydrophilic (water loving) polymers  either natural or synthetic.  Gelatine, agarose, carboy methyl cellulose, hydrophilic acrylates all can form hydrogels. We are quite familiar with hydrogels in our daily life, be it the jelly we eat  or the soft contact lenses that some of us insert into our eyes.  The similarity  of hydrogels with  soft biological tissues in terms of water content and texture has  made them the most desirable  biomaterials. 

However cartilage tissues, such as nails and skin contain more than 50% water but still possess superior mechanical properties. Nails are   hard and stiff  and skin is elastic. Scientists so far haven't been able to design such  hydrogels.  Now Rauner et al ( Technische Universitat Dortmund, Germany)  report a unique  calcification method to arrive at stiffer hydrogels by incorporating nanostructures of calcium phosphate into the gel body.  They  entrapped enzyme alkaline phosphatase in hydrophilic acrylate polymers and made these into films. The films were then dipped in water to swell, the swollen films were then immersed in an aqueous solution of calcium 2-glycerol phosphate(CaGP for short). As the hydrogels got irrigated with CaGP, the entrapped enzyme  began its duty of converting  CaGP  the  to calcium phosphate nano structures within bulk of the films. By varying the experimental conditions, such as duration, pH etc, the team could design optically transparent films with very high mechanical properties. To quote fracture energies of the order of 1300 joules per square meter and stiffness upto 440 megapascals,  several fold higher than cartilage and skin. Rauner and his team are confidant that these materials could be used as  "stiff scaffolds in tissue engineering for regenerative medicine and cell growth or as tough implants and carriers for drug delivery." 

Another report highlights the use of hydrogels for treatment of detached retinas.  As of now  a gas or silicone oil is used to push back and hold the detached retina in place while adhesion takes place.. Hayashi et al have developed an injectable hydrogel  which will prove to be simpler and more biocompatible. Stanley Chang at the Edward S Harkness Eye Institute attached tot the Columbia University Medical Centre USA  remarks that the gel could revolutionise the treatment of retinal detachment and other ocular disorders."

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And now an exciting venture from Skipping Rocks. To quote from their website 
Ooho! is a sustainable packaging alternative to plastic bottles and cups, made from a seaweed extract. It is entirely biodegradable and so natural you can actually eat it! Ooho sachets are flexible packets of water, drunk by tearing a hole and pouring into your mouth, or consumed whole. Our packaging is cheaper than plastic and can encapsulate any beverage including water, soft drinks, spirits, and even cosmetics.

See video at     Skipping Rocks Lab

REFERENCES:

1. Enzymatic mineralization generates ultrastiff and tough hydrogels with tunable mechanics

2. Fast-forming hydrogel with ultralow polymeric content as an artificial vitreous body

Breaking News from the Outer Space

The mysterious FRBs:

Astronomers are baffled by the FRBs (short for Fast Radio Bursts), persistent high energy signals from somewhere  far away, way  beyond our Galaxy. Detected almost a decade ago by Duncan Larimer of West Virginia University, initially  these were shrugged off as random noises. It was only last year  that researchers realised that at least one of them is a repeater with  signals  few thousands of a second long. Roughly 200 such signals have so far been received  from this repeater. And astronomers  estimate  the source could be  roughly 2.5 billion light years away.  It is still being debated whether the source is a faint dwarf galaxy or a a super powerful magentar, or an active galactic nuclei  or some thing else. Scientists   are treading vey cautiously  widening their horizons and peeping into other galaxies, assessing the  frequencies, checking for polarisation effects etc. Raw data will eventually do the talking, not speculation.  

SciFi  world writers and readers alike are  thrilled: they have been hoping to hear from E.T. ever since  he made friends with us.

  

Seven more Earths:

Humans  have an unexplainable fixation with number 7. Now Spitzer Space Telescope of NASA has   espied   seven earthlike planets revolving round a rather smaller sun. Because the Transiting Planets and Planetesimals Small Telescope located in Chile, did this spy work,  the new planetary system goes by the same name TRAPPIST-1. Michael Gillon, leader of Team TRAPPIST  says "The seven wonders of TRAPPIST-1 are the first Earth-size planets that have been found orbiting this kind of star".

Trappist-1 planetary system :An illustration Courtesy Hubble site 

The TRAPPIST-1 system seem to be a close knit family. So close that  a NASA report adds   "If a person was standing on one of the planet's surface, they could gaze up and potentially see geological features or clouds of neighbouring worlds, which would sometimes appear larger than the moon in Earth's sky. " Their orbital periods 1.51, 2.42,4.04, 6.06, 9.1 and 12.35 days respectively. And most important of all  Gillon et al state "their equilibrium temperatures are low enough to make possible the presence of liquid water on their surface !" But there is one hitch: the  short orbital periods imply the planets might be presenting  the same face to the Sun  like our Moon. 

Lay man is obsessed with just one question: will it support life as we know it?  As of now  it is difficult  to commit either way.  However   Ignas Stellan  at the Leiden Observatory, Leiden University  is absolutely certain about one thing -  the TRAPPIST  Sun has a very very long life span. It  will last for another 10 trillion years even after our own Sun has become nuclear ash,  because it is burning at an  extremely slow  rate. And in 10 trillion years anything can happen !

Ceres goes Organic 

NASA's DAWN spacecraft  has detected organic matter  on Ceres, the largest asteroid (or a  dwarf planet if you prefer) in the solar system. Dawn is equipped with  visible and Infrared spectrometers which can read out the chemical signatures of organic compounds.  Analysing  Dawn's data, the research team  suggests that the organics , linear carbon compounds, are native to Ceres.  It is presumed that the axial tilt facilitated accumulation of frozen water in the surface pockets  of Ceres.  The presence of clay and carbonate and now organics suggests chemical activity on Ceres  facilitated by a moist,  warm ambience.  

Chris Russell, principal investigator of the Dawn mission, based at the University of California, Los Angeles states that  "Dawn has revealed that Ceres is a diverse world that clearly had geological activity in its recent past.” 

Tailpiece

It has been more than a decade  since we downgraded and de-recognised Pluto.  However  there were/are many upset with that decision.  Efforts are on to bring Pluto and along with it many other cosmic bodies into the fold by redefining  a PLANET. The new definition runs like this:   

“ A planet is a substellar mass body that has never undergone nuclear fusion and that has sufficient self gravitation to assume a spheroidal shape adequately described by a triaxial ellipsoid regardless of its orbital parameters.” 

Or to put it bluntly as Nature Magazine: “Round objects in space that are smaller than stars.”

Aha do we see our dear Moon and all other moons of the solar system feeling elated at the possible upgradation?

Referencs:

1. A repeating fast radio burst Spitler L,.G et al Nature 531, 202-205 (2016)

2. A direct localization of a fast radio burst and its host Chatterjee, S et al Nature 541 58-61 (2017)

3. Seven temperate terrestrial planets around the nearby ultra cool dwarf star                 

    TRAPPIST-1: Gillon, M et al Nature 542,456-460 (2017)

4. Earth's seven sisters: Snellen, I.A.G. Nature 542, 421-423 (2017)

5  For more info on trappist1 

7. Dawn discovers evidence for organic material on Ceres

6. Pluto's Revenge: Nature Vol.542,23 Februar 2017 pp392

When communication goes viral

The new buzz word is viral; everything goes and grows viral these days-  Communication goes viral in an instant, thanks to the internet.   But how do the actual biological  viruses communicate , or do they communicate at all?  First report that they do  has appeared in the 26th January issue of Nature. 

But that was not the question a team scientists led by Prof. Rotem Sorek, Weizmann Institute asked. They were hoping to intercept bacterial communication. Bacteria are known to share information with descendants and close relatives  through chemical messengers.  The  process is referred to as quorum sensing. These  chemical messengers are small  peptide molecules whose presence and concentration level in the medium are signals  for the bacterial communities  to readjust or regulate their behaviour to maximise survival advantage.  The team set out to monitor the behaviour of Bacillus subtilis infected with various viruses.  Viruses  that infect   bacteria  are  called  bacteriophages  or simply phages. The word phage which has a Greek connection,  connotes gobbling up/consuming/annihilating. True, phages can gobble up their bacterial host, but there are times when they refrain from such an extreme step.  Here is the full story.  A  phage infecting a host  has two options :  either multiply  quickly and  kill of the host  or settle for a  live and let live policy temporarily, waiting for an opportune moment. The first one is called  lysis (or the lytic pathway)  and the second one is lysogeny (or  the Lysogenic Pathway).   Either way to counter the viral attack bacteria might put in place a defence strategy.  The Weizmann team   was  hoping to idenify and isolate messenger/s which  might provide clues  on the survival  strategies phage infected  bacteria might adopt.

The team  investigated  the  growth pattern of  Bacillus subtilis  infected with 4 different phages: phi29, phi105, rho14 and phi3T.  had hoped  to  spot a chemical messenger or messengers which facilitated bacterial communication.  But they were in for a surprise. Analysis of the bacterial broth infected with phi3T yielded   a small peptide molecule but it was  of viral origin.  Follow up studies established it to be a short peptide  used by the phi3T phage to communicate within its community, a kind of strategy signal to  successive generations.  Less of the peptide in the medium prompted the new generation  to get on a vigorous  lytic phase while   more of it in the medium proved to be  a warning signal   to get onto  dormant lysogenic phase. So in reality this was decision making process.  Excited, the  team gave an appropriate  name to the peptide-  arbitrium which in latin means decision.  The team also observed that during the initial stages of infection when bacteria to phage ratio is high, the concentration of arbitrium  in the medium is very low signalling  lytic phase.   During  the later stages of infection when almost all bacterial population is infected,  arbitrium  levels shoot up signalling new generations of the phages  to lie low  for the time being.    

References:

1.Communication between viruses guides lysis-lysogeny decisions:  Erez et al Nature vol541, pages 488-493,  January 26, 2017

2. Quorum sensing: cell to cell communication in bacteria: Waters & Bassler : Ann.Rev.Cell Dev.Biol  21:319-46 2005

  

Heart has its own defence

Hearts are made to be broken, so said Oscar Wilde.  Human heart handles emotional trauma in the classical  way with  time as the healer.  Pain slowly gets  relegated to the dark recess of memory and even if  it surfaces at times one  would have  by then learned the art of dealing with it. 

Work by BruceBlaus Wikipedia 

Now about physical damages. Medical world has  amazing ways of repairing and constructing damaged heart- bypass surgery, valve replacement, heart transplantation etc are easily said and as easily done too. Heart is a relentless machine.  Per day statistics runs roughly like this- about 100,000 beats which facilitates the pumping of  about 2000 gallons of oxygen rich blood through the aorta to reach every nook and corner of the body.  Heart's own needs are taken care of by the  left and right coronary arteries. These arteries divide and subdivide into smaller and smaller  branches  and  reach every fibre of the cardiac muscle. 

It has now been discovered that coronary arteries respond with ingenuity when confronted with blockages in their blood circulation network. They immediately presses  into action  dormant  channels called collateral  channels. Now collateral plumbing system is laid down at birth to be used in emergency.  When pressed into action  they bypass the blockage, reach blood and nutrients to the required spot.  With continued usage collateral channels  grow bigger and stronger and can restore  upto 40% efficiency.  In rare occasions  even brand new channels might be opened.  Dr Rubanyi who works in the area of cardiovascular therapeutics  is confident that heart can be coaxed to grow new blood vessels under duress.  Towards this end it is necessary to know under what circumstances collateral blood vessels  become active. 

There are indications that  vigorous physical exercise could be one of the factors that push blood into dormant collateral channels. But then there are patients  for whom even minimal physical exertion is a big NO NO. "Hence the search "  Dr Rubanyi says  "for the right combination of designer proteins, genes or cells to push the heart to expand its collateral network."  

References:

1. The heart therapy by  Gabor Rubanyi  Scientific American  January 2017

2.The human coronary circulation 

3.Long term physical exercise and quantitatively assessed human coronary collateral circulation