We recently reported on the radio-frequency attenuation length of cold polar ice at Summit Station, Greenland, based on bi-static radar measurements of radio-frequency bedrock echo strengths taken during the summer of 2021. Those data also allow studies of (a) the relative contributions of coherent (such as discrete internal conducting layers with sub-centimeter transverse scale) vs incoherent (e.g. bulk volumetric) scattering, (b) the magnitude of internal layer reflection coefficients, (c) limits on signal propagation velocity asymmetries (‘birefringence’) and (d) limits on signal dispersion in-ice over a bandwidth of ~100 MHz. We find that (1) attenuation lengths approach 1 km in our band, (2) after averaging 10 000 echo triggers, reflected signals observable over the thermal floor (to depths of ~1500 m) are consistent with being entirely coherent, (3) internal layer reflectivities are ≈–60$\to$–70 dB, (4) birefringent effects for vertically propagating signals are smaller by an order of magnitude relative to South Pole and (5) within our experimental limits, glacial ice is non-dispersive over the frequency band relevant for neutrino detection experiments.

Cardiac myxoma is a relatively rare tumour, usually solitary, that occurs primarily in the left atrium of adults, but comprises only 30% of cardiac tumours in children. We recently treated a 12-year-old girl with multiple recurrent myxomas in three cardiac chambers(following surgical resection 3 years earlier). Genomic analysis showed the PKAR1A mutation typical for Carney complex

SCAR, the Scientific Committee on Antarctic Research, is, like the IAU, a committee of ICSU, the International Council for Science. For over 30 years, SCAR has provided scientific advice to the Antarctic Treaty System and made numerous recommendations on a variety of matters. In 2010, Astronomy and Astrophysics from Antarctica was recognized as one of SCAR's five Scientific Research Programs. Broadly stated, the objectives of Astronomy & Astrophysics from Antarctica are to coordinate astronomical activities in Antarctica in a way that ensures the best possible outcomes from international investment in Antarctic astronomy, and maximizes the opportunities for productive interaction with other disciplines. There are four Working Groups, dealing with site testing, Arctic astronomy, science goals, and major new facilities. Membership of the Working Groups is open to any professional working in astronomy or a related field.

In May 2011, IceCube, a neutrino telescope with one cubic kilometer instrumented volume started full operation with 5,160 sensors. The plan to build an experiment of this scale was based in part on the successful realization of a prototype experiment, the Antarctic Muon and Neutrino Detector Array. Here, we will review some of the major challenges and milestones.

Our objective was to examine the neonatal outcome of second twins depending on presentation and mode of delivery. Using a database we analyzed the short-term neonatal outcome in twin pregnancies offered a trial of labor with special emphasis on the second twin depending on presentation and mode of delivery. Neonatal outcome was evaluated by Apgar scores, umbilical cord blood pH values, and perinatal or neonatal morbidity and mortality. Overall, in 219 (78%) of 281 pregnancies successful vaginal birth (VB) of both twins (VB–VB) was possible, 48 (17%) women had to be delivered by cesarean section (CS) of both twins (CS–CS), and in 14 (5%) women the second twin had to be delivered by CS after VB of the first twin (VB–CS). Successful VB was most common for vertex-vertex (V/V; n = 171, 82%) and vertex-nonvertex (n = 48, 75%) presentation (V/NV). Twins delivered by VB–CS had the lowest values for pHart (p = .006) and pHven (p = .010). pHart less than or equal to 7.00 values occurred only in second twins delivered VB–VB or VB–CS. Lower Apgar scores of the second twin occurred more frequently in the VB–CS and in the VB–VB than in the CS–CS groups (ps < .05). Lower levels of pHart (p = .002) and frequency of pHart less than or equal to 7.00 occurred more often in nonvertex second twins than in vertex second twins (p < .022). The high CS rate in V/NV presentation and the significantly worse perinatal short-term outcome of NV second twins after VB of the first twin underline that randomized studies are necessary to evaluate the best delivery mode for V/NV twins.

The AMANDA neutrino telescope, prototype instrument of the IceCube neutrino observatory at South Pole, has collected data since 2000 in its final configuration. A period of 1001 days of livetime between 2000 and 2004 has been analysed in order to find evidence of a neutrino signal coming from point-like sources such as microquasars, active galactic nuclei, supernovae remnants or gamma ray bursts. A sensitivity to fluxes of νμ + νμ + ντ + ντ of dΦ/dE =1.0 · 10−10 (E/TeV)−2 · TeV−1 cm−2 s−1 was reached in the energy range between 1.6 TeV and 1.6 PeV. No significant excess over the background has been found so far. Flux upper limits infered from this study can constrain certain neutrino emission models of X-ray binaries. IceCube will have a substantially higher sensitivity. Currently at 10% of its final extension, it will comprise 4800 optical sensors deployed along 80 strings by early 2011, instrumenting one cubic kilometre volume of ice and 1 km2 at the surface.