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$$
{\frac  {P_{{\mathrm  {gas}}}}{P_{{\mathrm  {deg}}}}}\approx 5\tau \chi ^{{-2}}~~~~~{\mathrm  {and}}~~~~~{\frac  {P_{{\mathrm  {rad}}}}{P_{{\mathrm  {deg}}}}}\approx {\biggl (}{\frac  {\pi ^{4}}{3}}{\biggr )}\tau ^{4}\chi ^{{-5}};
$$
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