  We measure the sum of the neutrino particle masses using the
three-dimensional galaxy power spectrum of the SDSS-III Baryon Oscillation
Spectroscopic Survey (BOSS) Data Release 9 (DR9) CMASS galaxy sample. Combined
with the cosmic microwave background (CMB), supernova (SN) and additional
baryonic acoustic oscillation (BAO) data, we find upper 95 percent confidence
limits of the neutrino mass $\Sigma m_{\nu}<0.340$ eV within a flat
$\Lambda$CDM background, and $\Sigma m_{\nu}<0.821$ eV, assuming a more general
background cosmological model. The number of neutrino species is measured to be
$N_{\rm eff}=4.308\pm0.794$ and $N_{\rm eff}=4.032^{+0.870}_{-0.894}$ for these
two cases respectively. We study and quantify the effect of several factors on
the neutrino measurements, including the galaxy power spectrum bias model, the
effect of redshift-space distortion, the cutoff scale of the power spectrum,
and the choice of additional data. The impact of neutrinos with unknown masses
on other cosmological parameter measurements is investigated. The fractional
matter density and the Hubble parameter are measured to be
$\Omega_M=0.2796\pm0.0097$, $H_0=69.72^{+0.90}_{-0.91}$ km/s/Mpc (flat
$\Lambda$CDM) and $\Omega_M=0.2798^{+0.0132}_{-0.0136}$,
$H_0=73.78^{+3.16}_{-3.17}$ km/s/Mpc (more general background model). Based on
a Chevallier-Polarski-Linder (CPL) parametrisation of the equation-of-state $w$
of dark energy, we find that $w=-1$ is consistent with observations, even
allowing for neutrinos. Similarly, the curvature \Omega_K and the running of
the spectral index $\alpha_s$ are both consistent with zero. The
tensor-to-scaler ratio is constrained down to $r<0.198$ (95 percent CL, flat
$\Lambda$ CDM) and $r<0.440$ (95 percent CL, more general background model).
