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Charles Daney

Is String Theory an Unphysical Pile of Garbage? : Starts With A Bang - 0 views

scienceblogs.com/...tring_theory_an_unphysical.php

string theory

shared by Charles Daney on 03 Oct 09 - Cached
  • Charles Daney on 03 Oct 09
     
    A central point to understanding string theory is that it cannot be formulated the way all other fundamental theories are, by giving the dynamical variables and the equations they obey. We do not know what the fundamental dynamical variables of string theory are, nor the equations they obey.
Ilmar Tehnas

Physicists investigate fate of five-dimensional black strings - 2 views

www.physorg.com/news203318795.html

physicists investigate fate multidimension

shared by Ilmar Tehnas on 11 Sep 10 - No Cached
  • Ilmar Tehnas on 11 Sep 10
     
    Extension of string theory.
Mike Chelen

RNA world easier to make : Nature News - 0 views

www.nature.com/...news.2009.471.html

rna

shared by Mike Chelen on 15 May 09 - No Cached
  • John Sutherland and his colleagues from the University of Manchester, UK
  • ribonucleotide
  • building block of RNA
  • ...29 more annotations...
  • Donna Blackmond, a chemist at Imperial College London.
  • strong evidence for the RNA world
  • 'RNA world' hypothesis, which suggests that life began when RNA, a polymer related to DNA that can duplicate itself and catalyse reactions
  • chemists had thought the subunits would probably assemble themselves first, then join to form a ribonucleotide
  • three distinct parts: a ribose sugar, a phosphate group and a base
  • RNA polymer is a string of ribonucleotides
  • efforts to connect ribose and base together have met with frustrating failure
  • researchers have now managed to synthesise
  • ribonucleotides
  • remedy is to avoid producing separate ribose-sugar and base subunits
  • makes a molecule whose scaffolding contains a bond that will
  • be the key ribose-base connection
  • atoms are then added around this skeleton
  • final connection is to add a phosphate group
  • influences the entire synthesis
  • acting as a catalyst, it guides small organic molecules into making the right connections
  • What we have ended up with is molecular choreography
  • objectors to the RNA-world theory say the RNA molecule as a whole is too complex to be created using early-Earth geochemistry
  • flaw is in the logic — that this experimental control by researchers in a modern laboratory could have been available on the early Earth
  • Robert Shapiro, a chemist at New York University
  • early-Earth scenarios
  • heating molecules in water, evaporating them and irradiating them with ultraviolet light
  • results showing that they can string nucleotides together
  • ultimate goal is to get a living system (RNA) emerging from a one-pot experiment
  • need to know what the constraints on the conditions are first
  • Shapiro sides with
  • another theory of life's origins
  • because RNA is too complex to emerge from small molecules, simpler metabolic processes
  • eventually catalysed the formation of RNA and DNA
Charles Daney

Technology Review: Life on moduli space? - 0 views

www.technologyreview.com/...post.aspx

string theory

shared by Charles Daney on 16 Aug 09 - Cached
  • Charles Daney on 16 Aug 09
     
    Is there something special about exact supersymmetry that precludes complex life?
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