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                  <mods:namePart>Díaz Díaz, Jesús Ildefonso</mods:namePart>
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                  <mods:namePart>Nagai, Toshitaka</mods:namePart>
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                  <mods:namePart>Rakotoson, Jean Michel Theresien</mods:namePart>
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                  <mods:dateIssued encoding="iso8601">1998-05-01</mods:dateIssued>
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               <mods:identifier type="issn">0022-0396</mods:identifier>
               <mods:identifier type="doi">10.1006/jdeq.1997.3389</mods:identifier>
               <mods:identifier type="uri">https://hdl.handle.net/20.500.14352/57385</mods:identifier>
               <mods:identifier type="officialurl">http://zv4fy5pr5l.scholar.serialssolutions.com/?sid=google&amp;auinit=JI&amp;aulast=Diaz&amp;atitle=Symmetrization+Techniques+on+Unbounded+Domains:+Application+to+a+Chemotaxis+System+on+UN&amp;title=Journal+of+Differential+Equations&amp;volume=145&amp;issue=1&amp;date=1998&amp;spage=156</mods:identifier>
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               <mods:abstract>The authors study the parabolic-elliptic system on RN: ∂u/∂t=∇⋅(∇u−χu∇v), 0=Δv−γv+αu, u(0,⋅)=u0, a version of the mathematical model of chemotaxis proposed by Keller and Segel. 
   A differential inequality for the quantity ∫s0u∗(t,σ)dσ, where u∗ is the decreasing rearrangement of the solution u(t,⋅) with respect to the spatial variable, is obtained. 
   As a consequence, they obtain e.g. Lp-bounds of the solution (u,v) on R2 and global-in-time existence of solutions under the condition αχ∫R2u0&lt;8π. This result is sharp. It is also proved that if u0 is radially symmetric and αχ∫R2u0>8π, then the solution (u,v) blows up in a finite time. Compared to the previous work of Díaz Díaz and Nagai [Adv. Math. Sci. Appl. 5 (1995), no. 2, 659--680; MR1361010 (96j:35246)], where this problem has been considered on bounded domains of RN, there are some additional technical difficulties connected with the regularity of the derivative ∂u∗/∂t.</mods:abstract>
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                  <mods:title>Symmetrization techniques on unbounded domains: Application to a chemotaxis system on R-N</mods:title>
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