Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Colour changes upon cooling of Lepidoptera scales containing photonic
  nanoarchitectures   The effects produced by the condensation of water vapours from the ambient in
the various intricate nanoarchitectures occurring in the wing scales of several
Lepidoptera species were investigated by controlled cooling (from room
temperature to -5 - -10 {\deg}C) combined with in situ measurement of changes
in the reflectance spectra. It was determined that, due to this procedure, all
photonic nanoarchitectures giving a reflectance maximum in the visible range
and having an open nanostructure exhibited alteration of the position of the
reflectance maximum associated with the photonic nanoarchitectures. The
photonic nanoarchitectures with a closed structure exhibited little to no
alteration in colour. Similarly, control specimens coloured by pigments did not
exhibit a colour change under the same conditions. Hence, this effect can be
used to identify species with open photonic nanoarchitectures in their scales.
For certain species, an almost complete disappearance of the reflectance
maximum was found. All specimens recovered their original colours following
warming and drying. Cooling experiments using thin copper wires demonstrated
that colour alterations could be limited to a millimetre, or below. Dried
museum specimens do not exhibit colour changes when cooled in the absence of a
heat sink due to the low heat capacity of the wings.

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The categories of this paper are: nucl-th
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The categories of this paper are: hep-lat
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The categories of this paper are: quant-ph
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The categories of this paper are: hep-ph
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The categories of this paper are: nucl-ex
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The categories of this paper are: stat
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The categories of this paper are: q-fin
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The categories of this paper are: supr-con
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The categories of this paper are: adap-org
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The categories of this paper are: funct-an
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The categories of this paper are: q-alg
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The categories of this paper are: bayes-an
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The categories of this paper are: solv-int
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The categories of this paper are: ao-sci
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The categories of this paper are: alg-geom
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The categories of this paper are: atom-ph