Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Rheology of Active Polymer-like T. Tubifex Worms   Of all complex fluids, it is probably the rheology of polymers we understand
best. In-depth insight into the entanglement and reptation of individual
polymers allows us to predict for instance the shear-thinning rheology and the
behaviour in virtually any flow situation of practical importance. The
situation is markedly different when we move from passive to active polymers
where the coupling of filament activity, hydrodynamic interactions, and
conformations open the way to a plethora of novel structural and dynamical
features. Here we experimentally study the rheology of long, slender and
entangled living worms (Tubifex tubifex) and propose this system as a new type
of active polymer. Its level of activity can be controlled by changing the
temperature or by adding small amounts of alcohol to make the worms temporarily
inactive. We find that (i) shear thinning is reduced by activity, (ii) the
characteristic shear rate for the onset of shear-thinning is given by the time
scale of the activity, and (iii) the low shear viscosity as a function of
concentration shows a very different scaling from that of regular polymers. Our
study paves the way towards a new research field of `living polymers'.

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The categories of this paper are: math-ph
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The categories of this paper are: patt-sol
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The categories of this paper are: alg-geom
2
The categories of this paper are: math
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The categories of this paper are: cmp-lg
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The categories of this paper are: nlin
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The categories of this paper are: solv-int
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The categories of this paper are: gr-qc
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The categories of this paper are: stat
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The categories of this paper are: quant-ph
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The categories of this paper are: atom-ph
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The categories of this paper are: chem-ph
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The categories of this paper are: q-alg
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The categories of this paper are: plasm-ph
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The categories of this paper are: dg-ga
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The categories of this paper are: econ