Revised Eocene-Oligocene kinematics for the West Antarctic rift system

Past plate motion between East and West Antarctica along the West Antarctic rift system had important regional and global implications. Although extensively studied, the kinematics of the rift during Eocene-Oligocene time still remains elusive. Based on a recent detailed aeromagnetic survey from the Adare and Northern Basins, located in the northwestern Ross Sea, we present the first well-constrained kinematic model with four rotations for Anomalies 12o, 13o, 16y, and 18o (26.5–40.13 Ma). These rotation poles form a cluster suggesting a stable sense of motion during that period of time. The poles are located close to the central part of the rift implying that the local motion varied from extension in the western Ross Sea sector (Adare Basin, Northern Basin, and Victoria Land Basin) to dextral transcurrent motion in the Ross Ice Shelf and to oblique convergence in the eastern end of the rift zone. The results confirm previous estimates of 95 km of extension in the Victoria Land Basin

Anti-Mullerian-Hormone during pregnancy and peripartum using the new Beckman Coulter AMH Gen II Assay

Background: AMH levels determined by the conventional AMH assay declined during pregnancy and postpartum. A new Beckman Coulter AMH Gen II assay removes the potentially assay-interfering complement which is activated in pregnancy. The aim of this study was to evaluate if the decline of AMH levels in the serum of pregnant women during the course of pregnancy and peripartum was assay-dependent and thus artificial. Methods: In this cross-sectional study prepartal blood samples were collected from 62 patients (median age 30.6 years [interquartile range: 25.6 - 34.5]) in the third trimester of pregnancy and again 1–4 days after delivery between 2011 and 2012. In another cohort of 11 patients (median age 34.1 years [interquartile range: 32.6 - 37.8]) blood samples were taken in different trimesters of pregnancy between 1995 and 2001. The conventional and the modified AMH assay were performed in the same patient serum samples. We used the conventional and the modified AMH-Gen-II ELISA (Beckman Coulter, Immunotech, Webster, USA) for the assessment of AMH levels. The Wilcoxon signed rank test was used for determining differences between AMH levels pre- and postpartum. The method of Bland and Altman was applied for analyzing the agreement of both methods for determining AMH levels. Results: AMH values peripartum were lower than those expected in fertile non-pregnant women of comparable age. An overall mean difference of 0.44 ng/ml was observed between the conventional and the modified assay. Measurements with the modified assay showed a significant decline of postpartal levels compared with prepartal levels which is consistent with values obtained using the conventional assay (both p < 0.00001). Compared to the longitudinal measurements of AMH levels determined using the conventional assay, AMH levels obtained using the modified assay suggest a steeper decline of values during the course of pregnancy. Conclusion: By comparing the conventional assay for AMH determination with the modified assay the present study confirmed that AMH levels decline during the course of pregnancy and early after delivery

New Antarctic gravity anomaly grid for enhanced geodetic and geophysical studies in Antarctica

Gravity surveying is challenging in Antarctica because of its hostile environment and inaccessibility. Nevertheless, many ground-based, airborne, and shipborne gravity campaigns have been completed by the geophysical and geodetic communities since the 1980s. We present the first modern Antarctic-wide gravity data compilation derived from 13 million data points covering an area of 10 million km2, which corresponds to 73% coverage of the continent. The remove-compute-restore technique was applied for gridding, which facilitated leveling of the different gravity data sets with respect to an Earth gravity model derived from satellite data alone. The resulting free-air and Bouguer gravity anomaly grids of 10 km resolution are publicly available. These grids will enable new high-resolution combined Earth gravity models to be derived and represent a major step forward toward solving the geodetic polar data gap problem. They provide a new tool to investigate continental-scale lithospheric structure and geological evolution of Antarctica

“Good Mothers Work”: How Maternal Employment Shapes Women’s Expectation of Work and Family in Contemporary Urban China

Drawing on 70 in‐depth interviews, I investigated how maternal employment shapes urban young Chinese women’s work–family expectation in a context of rapid social change. These interviews indicated that respondents attached strong moral meaning to mothers’ wage work, regarding it as integral to a “good” mother and an “ideal” woman. This moralization of maternal employment, in turn, led contemporary young Chinese women to view wage work as a taken‐for‐granted choice. Yet different from their own mothers, these young women were confronted with profound transformation across various domains of the postreform Chinese society. The normative expectation of women’s wage work, coupled with slow‐to‐change expectations about women’s roles at home and in a changing labor market, intensified young women’s burden of “doing it all.” This research highlights the importance of bringing the macro‐level context back into the mother–daughter dyad to understand the intergenerational transmission of gender beliefs and behavior.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/162814/2/josi12389_am.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/162814/1/josi12389.pd

New Magnetic Anomaly Map of the Antarctic

The second generation Antarctic magnetic anomaly compilation for the region south of 60 degrees S includes some 3.5 million line-km of aeromagnetic and marine magnetic data that more than doubles the initial map's near-surface database. For the new compilation, the magnetic data sets were corrected for the International Geomagnetic Reference Field, diurnal effects, and high-frequency errors and leveled, gridded, and stitched together. The new magnetic data further constrain the crustal architecture and geological evolution of the Antarctic Peninsula and the West Antarctic Rift System in West Antarctica, as well as Dronning Maud Land, the Gamburtsev Subglacial Mountains, the Prince Charles Mountains, Princess Elizabeth Land, and Wilkes Land in East Antarctica and the circumjacent oceanic margins. Overall, the magnetic anomaly compilation helps unify disparate regional geologic and geophysical studies by providing new constraints on major tectonic and magmatic processes that affected the Antarctic from Precambrian to Cenozoic times.Korea Polar Research Institute (KOPRI) programs, PM15040 and PE17050Germany's AWI/Helmholtz Center for Polar and Marine ResearchFederal Institute for Geosciences and Natural ResourcesBritish Antarctic Survey/Natural Environmental Research CouncilItalian Antarctic Research ProgrammeRussian Ministry of Natural ResourcesU.S. National Science Foundation and National Space and Aeronautics AdministrationAustralian Antarctic Division and Antarctic Climate & Ecosystem Cooperative Research CentreFrench Polar InstituteGlobal geomagnetic observatories network (INTERMAGNET

Air and shipborne magnetic surveys of the Antarctic into the 21st century

The Antarctic geomagnetics' community remains very active in crustal anomaly mapping. More than 1.5 million line-km of new air- and shipborne data have been acquired over the past decade by the international community in Antarctica. These new data together with surveys that previously were not in the public domain significantly upgrade the ADMAP compilation. Aeromagnetic flights over East Antarctica have been concentrated in the Transantarctic Mountains, the Prince Charles Mountains – Lambert Glacier area, and western Dronning Maud Land (DML) — Coats Land. Additionally, surveys were conducted over Lake Vostok and the western part of Marie Byrd Land by the US Support Office for Aerogeophysical Research projects and over the Amundsen Sea Embayment during the austral summer of 2004/2005 by a collaborative US/UK aerogeophysical campaign. New aeromagnetic data over the Gamburtsev Subglacial Mountains (120,000 line-km), acquired within the IPY Antarctica's Gamburtsev Province project reveal fundamental geologic features beneath the East Antarctic Ice sheet critical to understanding Precambrian continental growth processes. Roughly 100,000 line-km of magnetic data obtained within the International Collaboration for Exploration of the Cryosphere through Aerogeophysical Profiling promises to shed light on subglacial lithology and identify crustal boundaries for the central Antarctic Plate. Since the 1996/97 season, the Alfred Wegener Institute has collected 90,000 km of aeromagnetic data along a 1200 km long segment of the East Antarctic coast over western DML. Recent cruises by Australian, German, Japanese, Russian, British, and American researchers have contributed to long-standing studies of the Antarctic continental margin. Along the continental margin of East Antarctica west of Maud Rise to the George V Coast of Victoria Land, the Russian Polar Marine Geological Research Expedition and Geoscience Australia obtained 80,000 and 20,000 line-km, respectively, of integrated seismic, gravity and magnetic data. Additionally, US expeditions collected 128,000 line-km of shipborne magnetic data in the Ross Sea sector

Bedmap2: improved ice bed, surface and thickness datasets for Antarctica

We present Bedmap2, a new suite of gridded products describing surface elevation, ice-thickness and the seafloor and subglacial bed elevation of the Antarctic south of 60° S. We derived these products using data from a variety of sources, including many substantial surveys completed since the original Bedmap compilation (Bedmap1) in 2001. In particular, the Bedmap2 ice thickness grid is made from 25 million measurements, over two orders of magnitude more than were used in Bedmap1. In most parts of Antarctica the subglacial landscape is visible in much greater detail than was previously available and the improved data-coverage has in many areas revealed the full scale of mountain ranges, valleys, basins and troughs, only fragments of which were previously indicated in local surveys. The derived statistics for Bedmap2 show that the volume of ice contained in the Antarctic ice sheet (27 million km3) and its potential contribution to sea-level rise (58 m) are similar to those of Bedmap1, but the mean thickness of the ice sheet is 4.6% greater, the mean depth of the bed beneath the grounded ice sheet is 72 m lower and the area of ice sheet grounded on bed below sea level is increased by 10%. The Bedmap2 compilation highlights several areas beneath the ice sheet where the bed elevation is substantially lower than the deepest bed indicated by Bedmap1. These products, along with grids of data coverage and uncertainty, provide new opportunities for detailed modelling of the past and future evolution of the Antarctic ice sheets

Bedmap2: improved ice bed, surface and thickness datasets for Antarctica

We present Bedmap2, a new suite of gridded products describing surface elevation, ice-thickness and the seafloor and subglacial bed elevation of the Antarctic south of 60 S. We derived these products using data from a variety of sources, including many substantial surveys completed since the original Bedmap compilation (Bedmap1) in 2001. In particular, the Bedmap2 ice thickness grid is made from 25 million measurements, over two orders of magnitude more than were used in Bedmap1. In most parts of Antarctica the subglacial landscape is visible in much greater detail than was previously available and the improved datacoverage has in many areas revealed the full scale of mountain ranges, valleys, basins and troughs, only fragments of which were previously indicated in local surveys. The derived statistics for Bedmap2 show that the volume of ice contained in the Antarctic ice sheet (27 million km3) and its potential contribution to sea-level rise (58 m) are similar to those of Bedmap1, but the mean thickness of the ice sheet is 4.6% greater, the mean depth of the bed beneath the grounded ice sheet is 72m lower and the area of ice sheet grounded on bed below sea level is increased by 10 %. The Bedmap2 compilation highlights several areas beneath the ice sheet where the bed elevation is substantially lower than the deepest bed indicated by Bedmap1. These products, along with grids of data coverage and uncertainty, provide new opportunities for detailed modelling of the past and future evolution of the Antarctic ice sheets

Bedmap2: improved ice bed, surface and thickness datasets for Antarctica

We present Bedmap2, a new suite of gridded products describing surface elevation, ice-thickness and the seafloor and subglacial bed elevation of the Antarctic south of 60° S. We derived these products using data from a variety of sources, including many substantial surveys completed since the original Bedmap compilation (Bedmap1) in 2001. In particular, the Bedmap2 ice thickness grid is made from 25 million measurements, over two orders of magnitude more than were used in Bedmap1. In most parts of Antarctica the subglacial landscape is visible in much greater detail than was previously available and the improved data-coverage has in many areas revealed the full scale of mountain ranges, valleys, basins and troughs, only fragments of which were previously indicated in local surveys. The derived statistics for Bedmap2 show that the volume of ice contained in the Antarctic ice sheet (27 million km3) and its potential contribution to sea-level rise (58 m) are similar to those of Bedmap1, but the mean thickness of the ice sheet is 4.6% greater, the mean depth of the bed beneath the grounded ice sheet is 72 m lower and the area of ice sheet grounded on bed below sea level is increased by 10%. The Bedmap2 compilation highlights several areas beneath the ice sheet where the bed elevation is substantially lower than the deepest bed indicated by Bedmap1. These products, along with grids of data coverage and uncertainty, provide new opportunities for detailed modelling of the past and future evolution of the Antarctic ice sheets