Background Imaging of Cosmic Extragalactic Polarization (BICEP) is a bolometric polarimeter designed to measure the inflationary B-mode polarization of the cosmic microwave background (CMB) at degree angular scales. During three seasons of observing at the South Pole (2006 through 2008), BICEP mapped ∼ 2% of the sky chosen to be uniquely clean of polarized foreground emission. Here, we present initial results derived from a subset of the data acquired during the first two years. We present maps of temperature, Stokes Q and U, E and B modes, and associated angular power spectra. We demonstrate that the polarization data are self-consistent by performing a series of jackknife tests. We study potential systematic errors in detail and show that they are sub-dominant to the statistical errors. We measure the E-mode angular power spectrum with high precision at 21 ≤ ≤ 335, detecting for the first time the peak expected at ∼ 140. The measured E-mode spectrum is consistent with expectations from a ΛCDM model, and the B-mode spectrum is consistent with zero. The tensor-to-scalar ratio derived from the B-mode spectrum is r = 0.02 +0.31 −0.26 , or r < 0.72 at 95% confidence, the first meaningful constraint on the inflationary gravitational wave background to come directly from CMB B-mode polarization.

The Background Imaging of Cosmic Extragalactic Polarization (Bicep) experiment was designed specifically to search for the signature of inflationary gravitational waves in the polarization of the cosmic microwave background (CMB). Using a novel small-aperture refractor and 49 pairs of polarization-sensitive bolometers, Bicep has completed three years of successful observations at the South Pole beginning in 2006 February. To constrain the amplitude of the inflationary B-mode polarization, which is expected to be at least 7 orders of magnitude fainter than the 3 K CMB intensity, precise control of systematic effects is essential. This paper describes the characterization of potential systematic errors for the Bicep experiment, supplementing a companion paper on the initial cosmological results. Using the analysis pipelines for the experiment, we have simulated the impact of systematic errors on the B-mode polarization measurement. Guided by these simulations, we have established benchmarks for the characterization of critical instrumental properties including bolometer relative gains, beam mismatch, polarization orientation, telescope pointing, sidelobes, thermal stability, and timestream noise model. A comparison of the benchmarks with the measured values shows that we have characterized the instrument adequately to ensure that systematic errors do not limit Bicep's two-year results, and identifies which future refinements are likely necessary to probe inflationary B-mode polarization down to levels below a tensor-to-scalar ratio r = 0.1.

SUMMARYThis study demonstrates that the color vision of foraging Japanese yellow swallowtail butterflies, Papilio xuthus, involves simultaneous color contrast. We trained newly emerged Papilio to select a disk of pale green among a set of differently colored disks presented on a black background. When the same set of disks was presented on blue background, the pale green-trained butterflies selected blue-green. The difference in spectra between pale green and blue green was similar to the spectrum of yellow for human vision, suggesting that blue induces yellow. Similarly, the pale green-trained Papilio selected a more bluish spring green on yellow background. We also trained Papilio with orange disks and tested on a green and violet background. The results showed that green induced violet and vice versa. Taken together, we concluded that simultaneous color contrast of Papilio is similar to the effect of complementary colors in human color vision.

Background Completion lobectomy long after segmentectomy in the same lobe is extremely difficult because of severe adhesions around hilar structures, especially in cases involving video-assisted thoracoscopic surgery (VATS) completion lobectomy. We report and compare the surgical outcomes of patients who underwent VATS or thoracotomy completion lobectomy long after radical segmentectomy for lung cancer. Methods We retrospectively evaluated the surgical outcomes of completion lobectomies performed at our institute long after radical segmentectomies for lung cancer in the same lobe. The efficacy and safety of VATS completion lobectomy was compared to that of thoracotomy completion lobectomy. Results Ten of 228 patients who underwent radical segmentectomy for lung cancer between 2009 and 2018 underwent completion lobectomy at least a month after segmentectomy; five patients underwent VATS completion lobectomy. None of the patients underwent VATS left upper completion lobectomy, and conversion to thoracotomy was required in one patient. There were no significant differences between VATS and thoracotomy completion lobectomies in the median operative times (VATS 295 min, thoracotomy 339 min, p = 0.55), intraoperative blood loss volumes (VATS 350 mL, thoracotomy 500 mL, p = 0.84), intervals between initial segmentectomy and completion lobectomy (VATS 40 months, thoracotomy 48 months, p = 0.55), and number of patients with pulmonary artery injury (VATS 1, thoracotomy 2, p = 0.49). There was no operation-related mortality. Conclusions VATS completion lobectomy long after segmentectomy for lung cancer could be performed without fatal complications unless severe adhesions are observed around each main pulmonary artery.

BICEP1 is a millimeter-wavelength telescope designed specifically to measure the inflationary B-mode polarization of the cosmic microwave background at degree angular scales. We present results from an analysis of the data acquired during three seasons of observations at the South Pole (2006-2008). This work extends the two-year result published in Chiang et al., with additional data from the third season and relaxed detector-selection criteria. This analysis also introduces a more comprehensive estimation of band power window functions, improved likelihood estimation methods, and a new technique for deprojecting monopole temperature-to-polarization leakage that reduces this class of systematic uncertainty to a negligible level. We present maps of temperature, E-and B-mode polarization, and their associated angular power spectra. The improvement in the map noise level and polarization spectra error bars are consistent with the 52% increase in integration time relative to Chiang et al. We confirm both self-consistency of the polarization data and consistency with the two-year results. We measure the angular power spectra at 21 335 and find that the EE spectrum is consistent with Lambda cold dark matter cosmology, with the first acoustic peak of the EE spectrum now detected at 15σ. The BB spectrum remains consistent with zero. From B-modes only, we constrain the tensor-to-scalar ratio to r = 0.03 +0.