Burrowing Saves Lake Erie Clams

Native clams seem to have been protected from zebra mussel infestation at Metzger Marsh by the interaction between warm temperatures and soft sediments. Warm water encourages burrowing, but soft sediments are required to allow encrusted clams to burrow. In support of this conclusion, we have since found live unionids or fresh shells at three other Lake Erie wetlands

The Effects of Water-level Fluctuations on Vegetation in a Lake Huron Wetland.

The diversity and resultant habitat value of wetland plant communities in the Laurentian Great Lakes are dependent on water-level fluctuations of varying frequency and amplitude. Conceptual models have described the response of vegetation to alternating high and low lake levels, but few quantitative studies have documented the changes that occur. In response to recent concerns over shoreline management activities during an ongoing period of low lake levels in lakes Superior, Michigan, and Huron that began in 1999, we analyzed a quantitative data set from Saginaw Bay of Lake Huron collected from 1988 to 1993 during a previous lake-level decline to provide the needed information on vegetation responses. Transects were established that followed topographic contours with water-level histories that differed across a six-year period, ranging from barely flooded to dewatered for varying numbers of years to never dewatered. Percent cover data from randomly placed quadrats along those transects were analyzed to assess floristic changes over time, document development of distinct plant assemblages, and relate the results to lake-level changes. Ordinations showed that plant assemblages sorted out by transects that reflect differing water-level histories. Distinction of assemblages was maintained for at least three years, although the composition and positioning of those assemblages changed as lake levels changed. We present a model that uses orthogonal axes to plot transects by years out of water against distance above water and sorted those transects in a manner that matched ordination results. The model suggests that vegetation response following dewatering is dependent on both position along the water level/soil moisture gradient and length of time since dewatering. This study provided quantitative evidence that lake-level fluctuations drive vegetative change in Great Lakes wetlands, and it may assist in making decisions regarding shoreline management in areas that historically supported wetlands

Intensive Pedestrian Archaeological Survey of the Lower Segment of San Pedro Creek, South Alamo Street to the Apache-Alazán Creek Confluence, San Antonio, Bexar County, Texas

Raba Kistner Environmental, Inc. was contracted by Pape-Dawson Engineers, Inc., on behalf of the San Antonio River Authority, to perform an intensive archaeological pedestrian survey of the Lower Segment of San Pedro Creek. The northern boundary of the project area is the South Alamo Street Bridge, and the southern boundary is the confluence with Apache-Alazán Creek. The project area consisted of a 70- ft wide corridor along the center-line of San Pedro Creek. The field investigations were conducted over the course of three days in June of 2014. These days were preceded by several days of archival investigations to assess the types and degree of historic impacts within the project area. The fieldwork was followed by additional historic investigations and the analysis of the materials recovered and the consideration of recommendations associated with the planned project. The pedestrian survey was conducted under Texas Antiquities Committee permit number 6913, issued to Dr. Steve A. Tomka, who served as the Principal Investigator. Currently the project does not fall under the jurisdiction of Section 106 of the National Historic Preservation Act (NHPA) of 1966, although, proposed improvements may cause it to come under the regulations in the future. Kristi Miller Nichols served as Project Archaeologist. The field crew consisted of Chris Murray and Mark Luzmoor. As part of the project, a 100 percent intensive pedestrian survey of the Area of Potential Effect (APE) was conducted by Raba Kistner archaeologists. A total of fourteen shovel tests were excavated along the creek banks. The shovel tests encountered modern materials mixed with some potentially historic artifacts. Common items encountered included glass, plastic, and metal fragments. A total of three backhoe trenches were excavated in selected areas to search for deeply buried deposits along the bank, and to confirm the extensive disturbances within the APE. No significant cultural deposits were encountered during the course of the project. The shovel testing and backhoe trenching reveal extensive disturbances along the creek bank due to channelization and industrial activities that bordered San Pedro Creek spatially during the first half of the 20th century. Given the extent of disturbances within the APE and the lack of intact prehistoric or historic cultural deposits noted during the survey, RKEI suggests that the planned project will not impact significant buried cultural deposits within its APE. However, because the actual extent of impacts, their specific locations, their depth and their spatial extent is not known at this time, it is recommended that if extensive below ground excavations are needed to accomplish the goals of the project, archaeological monitors be available during construction. Monitoring should take place any time subsurface disturbances exceed 3-feet below the modern surface. San Pedro Springs and the creek which it forms have played a significant role in the region both prehistorically and historically and it is likely that pockets of significant undisturbed deposits may be present in the APE, even if they were not encountered during this survey. All curated materials, as well as all project related documents, will be temporarily housed at the RKEI Laboratory until permanently transferred to the curation facility at the University of Texas at San Antonio-Center for Archaeological Research, upon the acceptance of this draft final technical report

Numerical Evaluation of Micro-Pocket Fission Detectors

Micro-pocket fission detectors (MPFDs) are miniature fission chambers suitable for in-core neutron measurement that have been under development at Kansas State University for over one decade. Current-generation devices have been used at a number of university reactors (Kansas State, Wisconsin, and MIT) and as part of the first experiments performed during the recent restart of TREAT. Ongoing research aims to improve understanding of the existing MPFDs and to optimize designs for future deployment. To aid in this development, the dynamic response of a prototypic MPFD was evaluated using Garfield++, Elmer, Gmsh, and Stopping and Range of Ions in Matter (SRIM). Specifically, the finite-element code Elmer was used to calculate the electric field on a mesh generated by Gmsh. SRIM was used to compute the energy loss tables of the fission fragments in the gas. With output from Elmer and SRIM, Garfield++ was used to simulate the ionization process, the resulting electron drift, and the induced signal. This particular Garfield++ application was developed with hybrid parallelization based MPI and OpenMP. The performance of the MPFDs subjected to different temperatures and applied voltages was evaluated. The preliminary results indicate the fission fragment deposits a few MeV of energy in the gas, consistent with previous estimates. The pulses in the MPFDs can be formed in the nanosecond scale, thus accommodating high count rates and, hence, high neutron-flux levels. Ongoing work aims to extend this model and validate it against existing and planned experimental data

THE CHANDRA VARIABLE GUIDE STAR CATALOG

Variable stars have been identified among the optical-wavelength light curves of guide stars used for pointing control of the Chandra X-ray Observatory. We present a catalog of these variable stars along with their light curves and ancillary data. Variability was detected to a lower limit of 0.02 mag amplitude in the 4000-10000 Å range using the photometrically stable Aspect Camera on board the Chandra spacecraft. The Chandra Variable Guide Star Catalog (VGUIDE) contains 827 stars, of which 586 are classified as definitely variable and 241 are identified as possibly variable. Of the 586 definite variable stars, we believe 319 are new variable star identifications. Types of variables in the catalog include eclipsing binaries, pulsating stars, and rotating stars. The variability was detected during the course of normal verification of each Chandra pointing and results from analysis of over 75,000 guide star light curves from the Chandra mission. The VGUIDE catalog represents data from only about 9 years of the Chandra mission. Future releases of VGUIDE will include newly identified variable guide stars as the mission proceeds. An important advantage of the use of space data to identify and analyze variable stars is the relatively long observations that are available. The Chandra orbit allows for observations up to 2 days in length. Also, guide stars were often used multiple times for Chandra observations, so many of the stars in the VGUIDE catalog have multiple light curves available from various times in the mission. The catalog is presented as both online data associated with this paper and as a public Web interface. Light curves with data at the instrumental time resolution of about 2 s, overplotted with the data binned at 1 ks, can be viewed on the public Web interface and downloaded for further analysis. VGUIDE is a unique project using data collected during the mission that would otherwise be ignored. The stars available for use as Chandra guide stars are generally 6-11 mag and are commonly spectral types A and later. Due to the selection of guide stars entirely for positional convenience, this catalog avoids the possible bias of searching for variability in objects where it is to be expected. Statistics of variability compared to spectral type indicate the expected dominance of A-F stars as pulsators. Eclipsing binaries are consistently 20%-30% of the detected variables across all spectral types.United States. National Aeronautics and Space Administration (Smithsonian Astrophysical Observatory. Contract NAS8-03060)United States. National Aeronautics and Space Administration (Smithsonian Astrophysical Observatory. Contract SV3-73016

A study of the social and physical environment in catering kitchens and the role of the chef in promoting positive health and safety behaviour

This is the account of a mixed method study of chefs and their kitchens in order to identify the nature of their workplace and how this affects their ability to manage health and safety in the kitchen. It included extended periods of observation, monitoring of physical parameters, analysis of records of reported accidents, and a series of reflexive interviews. The findings were integrated and then fed back in a smaller number of second interviews in order to test whether the findings fitted in with the chefs' understanding of their world. Major factors identified included survival in a market environment, the status of the chef (and the kitchen) within organisations, marked autocracy of chefs, and an increasing tempo building up to service time with commensurate heat, noise, and activity. In particular during the crescendo, a threshold shift in risk tolerance was identified. The factors, their interplay, and their implications for health and safety in the catering kitchen are discussed

Transformational Solar Array Final Report

We have made outstanding progress in the Base Phase towards achieving the final NASA Research Announcement (NRA) goals. Progress is better than anticipated due to the lighter than predicted mass of the IMM solar cells. We look forward to further improvements in the IMM cell performance during Option I and Option II; so, we have confidence that the first four items listed in the table will improve to better than the NRA goals. The computation of the end of life blanket efficiency is uncertain because we have extrapolated the radiation damage from room temperature measurements. The last three items listed in the Table were not intended to be accomplished during the Base Phase; they will be achieved during Option I and Option II

Characterisation of MS phenotypes across the age span using a novel data set integrating 34 clinical trials (NO.MS cohort): age is a key contributor to presentation

Background: The Oxford Big Data Institute, multiple sclerosis (MS) physicians and Novartis aim to address unresolved questions in MS with a novel comprehensive clinical trial data set. Objective: The objective of this study is to describe the Novartis–Oxford MS (NO.MS) data set and to explore the relationships between age, disease activity and disease worsening across MS phenotypes. Methods: We report key characteristics of NO.MS. We modelled MS lesion formation, relapse frequency, brain volume change and disability worsening cross-sectionally, as a function of patients’ baseline age, using phase III study data (≈8000 patients). Results: NO.MS contains data of ≈35,000 patients (>200,000 brain images from ≈10,000 patients), with >10 years follow-up. (1) Focal disease activity is highest in paediatric patients and decreases with age, (2) brain volume loss is similar across age and phenotypes and (3) the youngest patients have the lowest likelihood (<25%) of disability worsening over 2 years while risk is higher (25%–75%) in older, disabled or progressive MS patients. Young patients benefit most from treatment. Conclusion: NO.MS will illuminate questions related to MS characterisation, progression and prognosis. Age modulates relapse frequency and, thus, the phenotypic presentation of MS. Disease worsening across all phenotypes is mediated by age and appears to some extent be independent from new focal inflammatory activity

How patients with multiple sclerosis acquire disability

Patients with multiple sclerosis acquire disability either through relapse-associated worsening (RAW) or progression independent of relapse activity (PIRA). This study addresses the relative contribution of relapses to disability worsening over the course of the disease, how early progression begins and the extent to which multiple sclerosis therapies delay disability accumulation. Using the Novartis-Oxford multiple sclerosis (NO.MS) data pool spanning all multiple sclerosis phenotypes and paediatric multiple sclerosis, we evaluated ∼200 000 Expanded Disability Status Scale (EDSS) transitions from >27 000 patients with ≤15 years follow-up. We analysed three datasets: (i) A full analysis dataset containing all observational and randomized controlled clinical trials in which disability and relapses were assessed (n = 27 328); (ii) all phase 3 clinical trials (n = 8346); and (iii) all placebo-controlled phase 3 clinical trials (n = 4970). We determined the relative importance of RAW and PIRA, investigated the role of relapses on all-cause disability worsening using Andersen-Gill models and observed the impact of the mechanism of worsening and disease-modifying therapies on the time to reach milestone disability levels using time continuous Markov models. PIRA started early in the disease process, occurred in all phenotypes and became the principal driver of disability accumulation in the progressive phase of the disease. Relapses significantly increased the hazard of all-cause disability worsening events; following a year in which relapses occurred (versus a year without relapses), the hazard increased by 31–48% (all P  Our data confirm that relapses contribute to the accumulation of disability, primarily early in multiple sclerosis. PIRA begins in relapsing-remitting multiple sclerosis and becomes the dominant driver of disability accumulation as the disease evolves. Pre-existing disability and older age are the principal risk factors for further disability accumulation. The use of disease-modifying therapies delays disability accrual by years, with the potential to gain time being highest in the earliest stages of multiple sclerosis

The Chandra Source Catalog

The Chandra Source Catalog (CSC) is a general purpose virtual X-ray astrophysics facility that provides access to a carefully selected set of generally useful quantities for individual X-ray sources, and is designed to satisfy the needs of a broad-based group of scientists, including those who may be less familiar with astronomical data analysis in the X-ray regime. The first release of the CSC includes information about 94,676 distinct X-ray sources detected in a subset of public ACIS imaging observations from roughly the first eight years of the Chandra mission. This release of the catalog includes point and compact sources with observed spatial extents <~ 30''. The catalog (1) provides access to the best estimates of the X-ray source properties for detected sources, with good scientific fidelity, and directly supports scientific analysis using the individual source data; (2) facilitates analysis of a wide range of statistical properties for classes of X-ray sources; and (3) provides efficient access to calibrated observational data and ancillary data products for individual X-ray sources, so that users can perform detailed further analysis using existing tools. The catalog includes real X-ray sources detected with flux estimates that are at least 3 times their estimated 1 sigma uncertainties in at least one energy band, while maintaining the number of spurious sources at a level of <~ 1 false source per field for a 100 ks observation. For each detected source, the CSC provides commonly tabulated quantities, including source position, extent, multi-band fluxes, hardness ratios, and variability statistics, derived from the observations in which the source is detected. In addition to these traditional catalog elements, for each X-ray source the CSC includes an extensive set of file-based data products that can be manipulated interactively.Comment: To appear in The Astrophysical Journal Supplement Series, 53 pages, 27 figure