We present new observations of the active star formation region NGC 1333 in the Perseus molecular cloud complex from the James Clerk Maxwell Telescope B-Fields In Star-forming Region Observations (BISTRO) survey with the POL-2 instrument. The BISTRO data cover the entire NGC 1333 complex (∼1.5 pc×2 pc) at 0.02 pc resolution and spatially resolve the polarized emission from individual filamentary structures for the first time. The inferred magnetic field structure is complex as a whole, with each individual filament aligned at different position angles relative to the local field orientation. We combine the BISTRO data with low-and high-resolution data derived from Planck and interferometers to study the multiscale magnetic field structure in this region. The magnetic field morphology drastically changes below a scale of ∼1 pc and remains continuous from the scales of filaments (∼0.1 pc) to that of protostellar envelopes (∼0.005 pc or ∼1000 au). Finally, we construct simple models in which we assume that the magnetic field is always perpendicular to the long axis of the filaments. We demonstrate that the observed variation of the relative orientation between the filament axes and the magnetic field angles are well reproduced by this model, taking into account the projection effects of the magnetic field and filaments relative to the plane of the sky. These projection effects may explain the apparent complexity of the magnetic field structure observed at the resolution of BISTRO data toward the filament network.

We report 850μm dust polarization observations of a low-mass (∼12 M e ) starless core in the ρ Ophiuchus cloud, Ophiuchus C, made with the POL-2 instrument on the James Clerk Maxwell Telescope (JCMT) as part of the JCMT B-fields In STar-forming Region Observations survey. We detect an ordered magnetic field projected on the plane of the sky in the starless core. The magnetic field across the ∼0.1pc core shows a predominant northeastsouthwest orientation centering between ∼40°and ∼100°, indicating that the field in the core is well aligned with the magnetic field in lower-density regions of the cloud probed by near-infrared observations and also the cloudscale magnetic field traced by Planck observations. The polarization percentage (P) decreases with increasing total intensity (I), with a power-law index of −1.03±0.05. We estimate the plane-of-sky field strength (B pos ) using modified Davis-Chandrasekhar-Fermi methods based on structure function (SF), autocorrelation function (ACF), and unsharp masking (UM) analyses. We find that the estimates from the SF, ACF, and UM methods yield strengths of 103±46 μG, 136±69 μG, and 213±115 μG, respectively. Our calculations suggest that the Ophiuchus C core is near magnetically critical or slightly magnetically supercritical (i.e., unstable to collapse). The total magnetic energy calculated from the SF method is comparable to the turbulent energy in Ophiuchus C, while the ACF method and the UM method only set upper limits for the total magnetic energy because of large uncertainties.

S. 2007. More on the validation of fecal samples for the large-scale study of dietary differences between two sympatric carnivores. Acta Theriologica 52: 307-315.Prey occurrence from stomach and fecal samples were compared in American marten Martes americana Turton, 1806, and fisher M. pennanti Erxleben, 1777. Diets were analyzed from stomach and fecal contents in four sex-age marten groups and four fisher groups, and dietary differences tested between species, sex, age and sample sources. Prey richness was compared between the two sample sources. Relative occurrence of dominant or co-dominant prey items did not differ between stomach and fecal samples in any of the groups. However, both series revealed inter-specific contrasts. Binomial correlations of prey occurrence between sample sources were significantly negative for most prey items. Correlations of prey richness between samples sources were not significant except in larger marten sample. Our results failed to reveal a bias in using fecal sample source. Thus we suggest that diet analyses using either sample source are valid when diets are assessed in a relatively large number of animals.

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