Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: The Jeans Instability in Presence of Viscous Effects   An analysis of the gravitational instability in presence of dissipative
effects is addressed. In particular, the standard Jeans Mechanism and the
generalization in treating the Universe expansion are both analyzed when bulk
viscosity affects the first-order Newtonian dynamics. As results, the
perturbation evolution is founded to be damped by dissipative processes and the
top-down mechanism of structure fragmentation is suppressed. In such a scheme,
the value of the Jeans Mass remains unchanged also in presence of viscosity.

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The categories of this paper are: cond-mat
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The categories of this paper are: atom-ph
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The categories of this paper are: nucl-ex
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The categories of this paper are: quant-ph
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The categories of this paper are: cs
14
The categories of this paper are: math-ph
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The categories of this paper are: q-fin
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The categories of this paper are: mtrl-th
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The categories of this paper are: cmp-lg
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The categories of this paper are: patt-sol
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The categories of this paper are: solv-int
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The categories of this paper are: chao-dyn
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The categories of this paper are: supr-con
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The categories of this paper are: alg-geom
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The categories of this paper are: q-bio
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The categories of this paper are: acc-phys