On the characteristics of Circumpolar Deep Water intrusions to the west Antarctic Peninsula Continental Shelf

Author Posting. © American Geophysical Union, 2009. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Journal of Geophysical Research 114 (2009): C05017, doi:10.1029/2008JC004955.Hydrographic and current velocity observations collected from March 2001 to February 2003 on the west Antarctic Peninsula shelf as part of the Southern Ocean Global Ecosystems Dynamics program are used to characterize intrusions of Upper Circumpolar Deep Water (UCDW) and Lower Circumpolar Deep Water (LCDW) onto the shelf and Marguerite Bay. UCDW is found on the middle and outer shelf along Marguerite Trough, which connects the shelf break to Marguerite Bay, and at another location farther south. UCDW intrudes in the form of frequent (four per month) and small horizontal scales (≈4 km) warm eddy-like structures with maximum vertical scales of a few hundred meters. However, no evidence of UCDW intrusions was found in Marguerite Bay. LCDW was found in several deep depressions connected to the shelf break, including Marguerite Trough, forming a tongue of relatively dense water 95 m thick (on average) that reaches into Marguerite Bay through Marguerite Trough. A steady advective-diffusive balance for the LCDW intrusion is used to make an estimation of the average upwelling rate and diffusivity in the deep layer within Marguerite Trough, which suggest the LCDW layer is renewed approximately every six weeks.This work was supported by the National Science Foundation Office of Polar programs through U.S. Southern Ocean GLOBEC grants OPP 99- 10092 and 06-23223. C. Moffat also received support from the Chilean government through its Presidential Fellowship program and the Coastal Ocean Institute at WHOI and the Cooperative Institute for Climate and Ocean Research at WHOI

Evidence for Innate and Adaptive Immune Responses in a Cohort of Intractable Pediatric Epilepsy Surgery Patients.

Brain-infiltrating lymphocytes (BILs) were isolated from resected brain tissue from 10 pediatric epilepsy patients who had undergone surgery for Hemimegalencephaly (HME) (n = 1), Tuberous sclerosis complex (TSC) (n = 2), Focal cortical dysplasia (FCD) (n = 4), and Rasmussen encephalitis (RE) (n = 3). Peripheral blood mononuclear cells (PBMCs) were also isolated from blood collected at the time of the surgery. Cells were immunostained with a panel of 20 antibody markers, and analyzed by mass cytometry. To identify and quantify the immune cell types in the samples, an unbiased clustering method was applied to the entire data set. More than 85 percent of the CD45+ cells isolated from resected RE brain tissue comprised T cells; by contrast NK cells and myeloid cells constituted 80-95 percent of the CD45+ cells isolated from the TSC and the FCD brain specimens. Three populations of myeloid cells made up >50 percent of all of the myeloid cells in all of the samples of which a population of HLA-DR+ CD11b+ CD4- cells comprised the vast majority of myeloid cells in the BIL fractions from the FCD and TSC cases. CD45RA+ HLA-DR- CD11b+ CD16+ NK cells constituted the major population of NK cells in the blood from all of the cases. This subset also comprised the majority of NK cells in BILs from the resected RE and HME brain tissue, whereas NK cells defined as CD45RA- HLA-DR+ CD11b- CD16- cells comprised 86-96 percent of the NK cells isolated from the FCD and TSC brain tissue. Thirteen different subsets of CD4 and CD8 αβ T cells and γδ T cells accounted for over 80% of the CD3+ T cells in all of the BIL and PBMC samples. At least 90 percent of the T cells in the RE BILs, 80 percent of the T cells in the HME BILs and 40-66 percent in the TSC and FCD BILs comprised activated antigen-experienced (CD45RO+ HLA-DR+ CD69+) T cells. We conclude that even in cases where there is no evidence for an infection or an immune disorder, activated peripheral immune cells may be present in epileptogenic areas of the brain, possibly in response to seizure-driven brain inflammation

Secondary Science and Mathematics Teachers’ Environmental Issues Engagement through SocioScientific Reasoning

Among the many responsibilities of K-12 educators is to promote the development of environmental literacy among their students. Contentious environmental issues are often considered socioscientific issues (SSI; e.g., climate change) in that they are rooted in science, but a myriad of non-scientific (e.g., cultural, political, economic, etc.) factors must be addressed if those issues are to be successfully resolved. Teachers often report being ill-equipped to address these non-scientific factors, which may be due to struggles with employing socioscientific reasoning (SSR). SSR includes understanding the complexity of SSI, engaging in perspective-taking and ongoing inquiry about SSI, employing skepticism when dealing with potentially biased information concerning SSI, and recognizing the affordances of science and non-science considerations in resolving those issues. In this study, mathematics and science teachers who engaged in an SSI-oriented professional development demonstrated a range of sophistication across the dimensions of SSR, with science teachers tending to exhibit more sophistication in their SSR than mathematics teachers. Herein, we share and discuss the results of the study, including the prompts and scoring rubrics with exemplars, which can be used to prepare teachers to teach about contentious SSI and enable them to more effectively instruct and evaluate their students when doing so

Robust Machine Learning Applied to Astronomical Datasets I: Star-Galaxy Classification of the SDSS DR3 Using Decision Trees

We provide classifications for all 143 million non-repeat photometric objects in the Third Data Release of the Sloan Digital Sky Survey (SDSS) using decision trees trained on 477,068 objects with SDSS spectroscopic data. We demonstrate that these star/galaxy classifications are expected to be reliable for approximately 22 million objects with r < ~20. The general machine learning environment Data-to-Knowledge and supercomputing resources enabled extensive investigation of the decision tree parameter space. This work presents the first public release of objects classified in this way for an entire SDSS data release. The objects are classified as either galaxy, star or nsng (neither star nor galaxy), with an associated probability for each class. To demonstrate how to effectively make use of these classifications, we perform several important tests. First, we detail selection criteria within the probability space defined by the three classes to extract samples of stars and galaxies to a given completeness and efficiency. Second, we investigate the efficacy of the classifications and the effect of extrapolating from the spectroscopic regime by performing blind tests on objects in the SDSS, 2dF Galaxy Redshift and 2dF QSO Redshift (2QZ) surveys. Given the photometric limits of our spectroscopic training data, we effectively begin to extrapolate past our star-galaxy training set at r ~ 18. By comparing the number counts of our training sample with the classified sources, however, we find that our efficiencies appear to remain robust to r ~ 20. As a result, we expect our classifications to be accurate for 900,000 galaxies and 6.7 million stars, and remain robust via extrapolation for a total of 8.0 million galaxies and 13.9 million stars. [Abridged]Comment: 27 pages, 12 figures, to be published in ApJ, uses emulateapj.cl

Southern Ocean GLOBEC moored array and automated weather station data report

Southern Ocean GLOBal ocean ECosystemsAs part of the U.S. Southern Ocean GLOBEC program, moored time series measurements of temperature, conductivity (salinity), pressure, velocity, and acoustic backscatter were made from March 2001 to March 2003 in and near Marguerite Bay, located on the Antarctic Peninsula western shelf. To monitor surface forcing during the moored array observations, two automatic weather stations (AWSs) were deployed on islands in Marguerite Bay and time series of wind, air temperature, pressure, and relative humidity were collected from May 2001 through March 2003. This report describes the individual moorings, their locations and local bathymetry, the instrumentation used and measurement depths, calibration and data processing steps taken to produce final time series, and basic plots of the final time series. The AWS data acquisition and processing are also described and basic plots of the final meteorological time series presented. Directions are given about how to access the raw and processed moored and AWS data via the SO GLOBEC website (http://globec.whoi.edu/jg/dir/globec/soglobec/).Funding was provided by the National Science Foundation under contract number OPP-99-10092

The Varga Site: A Multicomponent, Stratified Campsite in the Canyonlands of Edwards County, Texas

Data recovery excavations at the Varga Site were conducted in two phases during 2002 by archeologists from the Cultural Resources Department of TRC Environmental Corporation’s (TRC’s) Austin office under contract to Texas Department of Transportation (TxDOT) Scientific Service Contract No. 572XXSA004. This mitigation program was necessitated by the proposed reconstruction of the crossing of a Ranch to Market Road over Hackberry Creek, immediately south of the site in northeastern Edwards County. These archeological investigations were conducted as part of the responsibilities of TxDOT under existing federal and state legislation for the protection of cultural resources. Geoarcheological trenching and hand-excavations within the existing 31 m wide road right-of-way of 7- m-wide paved Ranch to Market Road focused on the alluvial fines in the first terrace overlooking Hackberry Creek immediately adjacent to a spring. The southern edge of the terrace contains relatively fine-grained sediments ranging from 15 to 150 centimeter (cm) thick that overlie coarse stream gravels that extend to an unknown depth. The modern ground surface had been impacted by road construction and maintenance activities, as well as by light erosion. Block Excavations were conducted on both sides of the pavement and resulted in the hand-excavations of a total of 207.75 square meters (m2), including 83 m2 (66.2 m3) in Block A on the western side and a 124.75 m2 (38.26 m3) area in Block B on the eastern side. Archeological deposits in the investigated part of the site extend to the southern lip of the first terrace and extend about 50 m to the north. The excavations yielded evidence of a multiple component campsite with three distinct and a fourth less distinct prehistoric components. In Block A, the 100 to 150 cm thick fine-grained sediments yielded four intact cultural components. Block B only targeted the youngest, Toyah component. The fine-grained alluvial sediments that comprise the first terrace contain discrete occupations radiocarbon dated to the Late Prehistoric period Toyah phase (ca. 290 to 660 B.P.), the Late Archaic period (ca. 1,700 to 2,300 B.P.), and the Early Archaic period (ca. 5,200 to 6,300 B.P.). A Middle Archaic period (ca. 3,900 to 4,800 B.P.) component was also recognized, but was not as clearly defined as were the other three components. Krotovina disturbance was relatively extensive in parts of the investigated site area. Nevertheless, the archeological deposits exhibited a high degree of contextual integrity. The Toyah phase component contains a rich assemblage of cultural material (ca. 65,000 pieces), including lithic debitage (ca. 26,000), quantities of highly fragmented bones (ca. 18,700), small burned rocks (ca. 16,000), formal and informal stone tools (ca. 1,850), scattered ceramic sherds (ca. 100), and 11 burned rock features. This component was radiocarbon dated by 14 accepted dates to between 290 and 660 B.P. Preservation was generally good, but mixing and probable overprinting contributed to poor horizontal patterning and an inability to identify discrete activity areas. The Late Archaic period component consists primarily of a large, nearly 6 m diameter lens of burned rock that is interpreted as an incipient burned rock midden with an indistinct central pit oven. This feature was associated with a buried A horizon and exhibited a high degree of stratigraphic integrity. However, beyond the ill-defined boundaries of this burned rock feature, limited lithic debitage assemblage (ca. 1,800), a few mussel shell fragments, five isolated burned rock features, scattered burned rocks, and occasional chipped stone tools (ca. 30) totaling less than 6,000 pieces. Identified dart point styles associated with this midden include Frio, Marcos, Ensor, Castroville, and Edgewood. This component was radiocarbon dated by 11 accepted dates to a 600-year period between 1,700 and 2,310 B.P. The Middle Archaic component was not well-defined, but definitely present and dispersed below the Late Archaic component and above the Early Archaic component. These materials were vertically distributed over a 20 to 40 cm thick zone that lacked completely sterile levels or visible breaks in the stratigraphy between the other cultural events. Lithic debitage (ca. 4,400) dominates the recovered assemblage (ca. 6,000), with limited burned rocks (ca. 3,000), a few formal chipped stone tools (ca. 25), and moderate frequency of vertebrate remains (100 g) also present. Two poorly organized burned rock features were also identified and documented. Five Early Triangular projectile points and one Carrizo point fragment occurred within this component. Two wood charcoal assays and one radiocarbon date on a deer bone directly date this Middle Archaic component to ca. 900-radiocarbon year period between 3,910 and 4,820 B.P. These three absolute dates are stratigraphically in order compared to the radiocarbon dates from the cultural components above and below. The Early Archaic component was defined by quantities of dense cultural debris (ca. 135,000) within a roughly 30 cm thick zone directly on top and mixed into coarse river gravels and below the Middle Archaic component. The cultural material varied in depth from a shallow 50 cm below datum (bd) at the north end to a much deeper 120 cmbd in the southern end of Block A. The recovery of a robust assemblage of dart points (170 specimens) that consisted of Group 2—Early Corner-Notched, Bandy, Martindale, Gower, and Merrell dart points indicates that this zone represents many occupations that occurred over a relatively broad time frame. The dart points were associated with a diverse tool assemblage (ca. 1,300). Organic preservation was poor in this lower stratum, but occasional fragments of animal bone, plant seeds, and wood charcoal were recovered. Fifteen organic samples of diverse materials yielded radiocarbon dates that document a minimum use period of 1,080-radiocarbon years from 5,200 B.P. to 6,280 B.P. Greater insight and understanding of each of these four components represented was made possible through the employment of numerous technical analyses, including the radiocarbon dating of 66 samples, six optically stimulated luminescence dates, use-wear analysis and organic residue identifications on 156 stone specimens, petrographic analyses on 18 pottery and one local sediment samples, pollen and phytolith analyses on 25 paired samples, instrumental neutron activation analysis on 261 chert samples and 18 pottery sherds, fatty acid composition on eight pottery sherds and 94 burned rocks, stable carbon and nitrogen analyses on 112 samples, macrobotanical analyses on 44 float and 75 individual charcoal samples, and granulometric and compositional studies on 10 sediment samples. The combined results have contributed significantly to a greater understanding of the Varga Site as a whole and documented specific information concerning the behaviors of the people who occupied the site. These and other technical analyses are urged for other excavated sites in the future to continue to broaden our understanding of the human behaviors at specific sites and throughout the broader region. This will add to a growing database that will foster a better understanding of prehistoric lifeways across Texas

Ocean variability contributing to basal melt rate near the ice front of Ross Ice Shelf, Antarctica

Author Posting. © American Geophysical Union, 2014. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Journal of Geophysical Research: Oceans 119 (2014): 4214–4233, doi:10.1002/2014JC009792.Basal melting of ice shelves is an important, but poorly understood, cause of Antarctic ice sheet mass loss and freshwater production. We use data from two moorings deployed through Ross Ice Shelf, ∼6 and ∼16 km south of the ice front east of Ross Island, and numerical models to show how the basal melting rate near the ice front depends on sub-ice-shelf ocean variability. The moorings measured water velocity, conductivity, and temperature for ∼2 months starting in late November 2010. About half of the current velocity variance was due to tides, predominantly diurnal components, with the remainder due to subtidal oscillations with periods of a few days. Subtidal variability was dominated by barotropic currents that were large until mid-December and significantly reduced afterward. Subtidal currents were correlated between moorings but uncorrelated with local winds, suggesting the presence of waves or eddies that may be associated with the abrupt change in water column thickness and strong hydrographic gradients at the ice front. Estimated melt rate was ∼1.2 ± 0.5 m a−1 at each site during the deployment period, consistent with measured trends in ice surface elevation from GPS time series. The models predicted similar annual-averaged melt rates with a strong annual cycle related to seasonal provision of warm water to the ice base. These results show that accurately modeling the high spatial and temporal ocean variability close to the ice-shelf front is critical to predicting time-dependent and mean values of meltwater production and ice-shelf thinning.The Woods Hole Oceanographic Institution (WHOI) participation in the ANDRILL Coulman High Program was supported by the National Science Foundation Office of Polar Programs (NSF ANT-0839108) through a subcontract from the University of Nebraska, Lincoln (UNL 25-0550-0004-004). I. Arzeno was supported as a 2011 WHOI Summer Student Fellow through the NSF Research Experiences for Undergraduates program (OCE- 0649139). L. Padman and S. Springer were supported by NASA grant NNX10AG19G to Earth & Space Research (ESR). M. Williams and C. Stewart were supported by the New Zealand National Institute of Water and Atmosphere (NIWA) core funding under the National Climate Centre, and the Ministry of Business, Innovation, and Employment (Contract CO5X1001).2015-01-0

Estimating sea-ice coverage, draft, and velocity in Marguerite Bay (Antarctica) using a subsurface moored upward-looking acoustic Doppler current profiler (ADCP)

Author Posting. © Elsevier B.V., 2007. This is the author's version of the work. It is posted here by permission of Elsevier B.V. for personal use, not for redistribution. The definitive version was published in Deep Sea Research Part II: Topical Studies in Oceanography 55 (2008): 351-364, doi:10.1016/j.dsr2.2007.11.004.A technique for the analysis of data from a subsurface moored upward-looking acoustic Doppler current profiler (ADCP) to determine ice coverage, draft and velocity is presented and applied to data collected in Marguerite Bay on the western Antarctic Peninsula shelf. This method provides sea ice information when no dedicated upward-looking sonar (ULS) data is available. Ice detection is accomplished using windowed variances of ADCP vertical velocity, vertical error velocity, and surface horizontal speed. ADCP signal correlation and backscatter intensity were poor indicators of the presence of ice at this site. Ice draft is estimated using a combination of ADCP backscatter data, atmospheric and oceanic pressure data, and information about the thermal stratification. This estimate requires corrections to the ADCP-derived range for instrument tilt and sound speed profile. Uncertainties of ± 0.20 m during midwinter and ± 0.40 m when the base of the surface mixed layer is above the ADCP for ice draft are estimated based on (a) a Monte Carlo simulation, (b) uncertainty in the sound speed correction, and (c) performance of the zero-draft estimate during times of known open water. Ice velocity is taken as the ADCP horizontal velocity in the depth bin specified by the range estimate.This work was supported by the NSF Office of Polar Programs through U.S. Southern Ocean GLOBEC grants OPP 99-10092 and OPP 06-23223, the WHOI Smith Chair in Coastal Oceanography, and the WHOI Education Office