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Changes of structural properties of tobermorite in autoclaved aerated concrete (AAC) for various compositions were characterized and the disadvantages of SEM analysis in this context are discussed. The influence of variations in the chemical composition of raw materials on lattice parameters, morphology and domain sizes of tobermorite was investigated by XRD and for comparison by SEM analysis. Particularly the effect of substitution by Al3+ and (SO4)2− in tobermorite structure was examined. The dimensions of coherently scattering domains were calculated based on the refinement of anisotropic peak broadening of tobermorite in XRD diffractograms using a Rietveld compatible approach. No effect of (SO4)2− on the domain sizes and lattice parameters of tobermorite could be observed. The amount of anhydrite detected by quantitative XRD analysis indicates that all of the available (SO4)2− is present as anhydrite. Lath-like shapes of domains and a larger c parameter are calculated whenever Al3+ is incorporated in a considerable amount. Formation of katoite can be observed very clearly in SEM micrographs whenever the amount of available Al3+ exceeds a distinct value in the dry mix. The effect of Al3+ and (SO4)2− on tobermorite morphology could not be observed clearly by SEM analysis in AAC samples.
Drilling the WDC06A borehole at the West Antarctic Ice Sheet (WAIS) Divide with the Deep Ice Sheet Coring (DISC) drill began in December 2007 and was successfully completed in December 2011 to a depth of 3405 m. The design and construction of a replicate coring system for use with the existing DISC drill began in 2010. In January 2012, the new replicate coring system was tested in the parent borehole at WAIS Divide. While a full deviation was not completed during the test period, much was learned about the mechanical, electrical and operational aspects of the system. Extensive testing and modifications were done over the northern/boreal summer to prepare the system for the upcoming and final season of the project. Further tuning of the system continued during the 2012/13 field season at WAIS Divide. This paper identifies the issues found with the system during the initial test season and discusses solutions, methods and testing done to arrive at an operational system.
The deep ice-sheet coring (DISC) drill was used for production ice-core drilling at WAIS Divide in Antarctica for six field seasons between 2007 and 2013. Continuous ice-core samples were obtained between the snow surface and 3405 m depth. During the 2012/13 austral summer, the DISC drill’s newly designed replicate ice-coring system was utilized to collect nearly 285m of additional high-quality core samples at depths of high scientific interest. Annual progress graphs are described, as well as milestones achieved over the course of the project. Drilling operations, challenges encountered, drill fluid usage, drilling results, and the drill crew’s experiences with the DISC drill and replicate coring system during production drilling are described and discussed in detail. Core-processing operations are described briefly, as well as the logistical undertaking of the DISC drill’s deployment to Antarctica.
The drilling of a deep borehole in ice is an undertaking that spans several seasons. Over recent decades such drilling has become widespread in both polar regions. Owing to the remoteness of the drill sites, considerable cost is associated with the drilling of a deep borehole of several thousand meters. The replicate coring system allows re-drilling of ice core at select depths within an existing parent borehole. This effectively increases the yield of the existing borehole and permits re-sampling of ice in areas of high scientific value. The replicate coring system achieves this through the combination of actuators, motors, sensors and a computerized control system. The replicate coring drill is a further development of the deep ice-sheet coring (DISC) drill, extending the capabilities of the DISC drill to include replicate coring.
The Blue Ice Drill (BID) is a large-diameter agile drill system designed by the Ice Drilling Design and Operations group of the University of Wisconsin–Madison to quickly core-clean 241 mm diameter ice samples from near-surface sites. It consists of a down-hole motor/gear reducer rotating a coring cutter and core barrel inside an outer barrel for efficient cuttings transport in solid ice. A variable-frequency drive and custom control box regulates electrical power to the drill. Torque reaction is accomplished on the surface via handles attached to a torsion stem. Core recovery is achieved with either core dogs in the sonde or with a separate core recovery tool. All down-hole tools are suspended on a collapsible tripod via ropes running on a capstan winch. The BID is operated by a minimum of two people and has been used successfully during two seasons of coring on a blue ice area of Taylor Glacier, Antarctica. An updated version of the drill system, BID-Deep, has been designed to recover cores to depths up to 200 m.
The replicate ice-coring system was developed by Ice Drilling Design and Operations (IDDO) for the US National Science Foundation. The design of the system leverages the existing infrastructure of the deep ice-sheet coring (DISC) drill to create a steerable drill capable of recovering replicate core at any targeted depth in an existing borehole. Critical requirements of the system include: collecting up to 400 m of core from the high side of an open hole; maintaining access to the entire borehole for logging tools; collecting up to four cores at a single depth; and operating to a depth of 4000m at −55°C and 34 MPa. The system was developed and tested from 2010 through 2012 and integrates several new mechanical subsystems, including two electromechanical actuators capable of pushing the sonde to any targeted azimuth, new reduced diameter core and screen barrels made from off-the-shelf casing tube, and new cutter heads optimized for the multiple stages of the replicate coring procedure. The system was successfully deployed at West Antarctic Ice Sheet (WAIS) Divide in the 2012/13 field season, recovering 285 m of core from five intentional deviations at four target depths.
In this study, the application of (an)isotropic size determination using a recently proposed model for the double-Voigt approach is demonstrated and validated against line profile simulations using the Whole Powder Pattern Modelling approach. The fitting of simulated line profiles demonstrates that the attained crystallite sizes and morphologies are in very reasonable agreement with the simulated values and thus demonstrate that even in routine application scenarios credible size and morphology information can be obtained using the double-Voigt approximation. The aim of this contribution is to provide a comprehensive introduction to the problem, address the practical application of the developed model, and discuss the accuracy of the double-Voigt approach and derived size parameters. Mathematical formulations for the visualization of modeled morphologies, supporting the application of the recently developed macros, are additionally provided.
To detail the activities of the Veterans Health Administration (VHA) Antimicrobial Stewardship Initiative and evaluate outcomes of the program.
The VHA is a large integrated healthcare system serving approximately 6 million individuals annually at more than 140 medical facilities.
Utilization of nationally developed resources, proportional distribution of antibiotics, changes in stewardship practices and patient safety measures were reported. In addition, inpatient antimicrobial use was evaluated before and after implementation of national stewardship activities.
Nationally developed stewardship resources were well utilized, and many stewardship practices significantly increased, including development of written stewardship policies at 92% of facilities by 2015 (P<.05). While the proportional distribution of antibiotics did not change, inpatient antibiotic use significantly decreased after VHA Antimicrobial Stewardship Initiative activities began (P<.0001). A 12% decrease in antibiotic use was noted overall. The VHA has also noted significantly declining use of antimicrobials prescribed for resistant Gram-negative organisms, including carbapenems, as well as declining hospital readmission and mortality rates. Concurrently, the VHA reported decreasing rates of Clostridium difficile infection.
The VHA National Antimicrobial Stewardship Initiative includes continuing education, disease-specific guidelines, and development of example policies in addition to other highly utilized resources. While no specific ideal level of antimicrobial utilization has been established, the VHA has shown that improving antimicrobial usage in a large healthcare system may be achieved through national guidance and resources with local implementation of antimicrobial stewardship programs.
This paper describes strategies to search for, detect, and identify organic material on the surface and subsurface of Mars. The strategies described include those applied by landed missions in the past and those that will be applied in the future. The value and role of ESA's ExoMars rover and of her key science instrument Mars Organic Molecule Analyzer (MOMA) are critically assessed.
Public interest in food systems has grown dramatically, and agricultural economists have important roles to play in contributing to and leading large-scale interdisciplinary studies of the subject. Key topics include understanding food system participants' behaviors and incentives and determining what food systems can and cannot achieve. I review a global food-security project funded by the National Institute of Food and Agriculture that illustrates the interactions between production, distribution, and consumption of food and regional self-reliance, as well as other important areas in which agricultural and regional economists can gainfully apply their tools and methods, including studies of the impacts of local food and network analyses.
Prelimary results of an extended program of coordinated X-ray and optical observations of TT Ari are presented. The object was observed on August 21/22 1985 both in X-rays (EXOSAT) and optical range, about 100 days after the return to the active state. The first detailed simultaneous study of TT Ari in active state indicates the presence of strongly absorbing structure in the system.
We present preliminary results of the EXOSAT X-ray observations and quasisimultaneous and simultaneous optical photometry of the X-ray source EX0020528+1454.8 = 1E0205+149 found independently as an serendipitous source both with Einstein and EXOSAT satellites. The optical counterpart is a pair of dMe stars, Our results indicate that the object is variable both in X-rays and optical wavelenghts, and probably belongs to dMe flare stars.
Antimicrobial stewardship programs (ASPs) are variably implemented.
To characterize variations of antimicrobial stewardship structure and practices across all inpatient Veterans Affairs facilities in 2012 and correlate key characteristics with antimicrobial usage.
A web-based survey regarding stewardship activities was administered to each facility’s designated contact. Bivariate associations between facility characteristics and inpatient antimicrobial use during 2012 were determined.
Total of 130 Veterans Affairs facilities with inpatient services.
Of 130 responding facilities, 29 (22%) had a formal policy establishing an ASP, and 12 (9%) had an approved ASP business plan. Antimicrobial stewardship teams were present in 49 facilities (38%); 34 teams included a clinical pharmacist with formal infectious diseases (ID) training. Stewardship activities varied across facilities, including development of yearly antibiograms (122 [94%]), formulary restrictions (120 [92%]), stop orders for antimicrobial duration (98 [75%]), and written clinical pathways for specific conditions (96 [74%]). Decreased antimicrobial usage was associated with having at least 1 full-time ID physician (P=.03), an ID fellowship program (P=.003), and a clinical pharmacist with formal ID training (P=.006) as well as frequency of systematic patient-level reviews of antimicrobial use (P=.01) and having a policy to address antimicrobial use in the context of Clostridium difficile infection (P=.01). Stop orders for antimicrobial duration were associated with increased use (P=.03).
ASP-related activities varied considerably. Decreased antibiotic use appeared related to ID presence and certain select practices. Further statistical assessments may help optimize antimicrobial practices.
Aspiration is the introduction of oropharyngeal or gastric contents into the respiratory tract. Three major syndromes may develop as a consequence of aspiration: chemical pneumonitis, bronchial obstruction secondary to aspiration of particulate matter, and bacterial aspiration pneumonia. Less commonly, interstitial lung disease occurs in persons with chronic aspiration. Which of these consequences emerges is determined by the amount and nature of the aspirated material as well as by the integrity of host defense mechanisms.
The term aspiration pneumonia refers to the infectious consequences of introduction of relatively large volumes of oral material into the lower airways (macroaspiration). Although healthy persons frequently aspirate small volumes of pharyngeal secretions during sleep, the development of pneumonia after such microaspiration is normally prevented by mechanical (e.g., cough and mucociliary transport) and immunologic responses. Pneumonia arises when these host defenses are not able to limit bacterial proliferation either because of microaspiration of highly virulent pathogens to which the host lacks specific immunity (e.g., Streptococcus pneumoniae or enteric gram-negative bacteria) or because of macroaspiration of large quantities of organisms that may not necessarily be highly virulent.
Aspiration may be clinically obvious, as when acute pulmonary complications follow inhalation of vomited gastric contents. Such acute chemical pneumonitis, representing damage to lung parenchyma by highly acidic gastric contents, is often referred to as Mendelson’s syndrome. On the other extreme, so-called silent aspiration, as occurs in persons with neurologic impairment who lack cough responses, is often followed by the indolent onset of infectious pneumonia consequent to contamination of the lower airways by low virulence mixtures of aerobic and anaerobic microorganisms from the oropharynx.
A general analysis of the hydrodynamic limit of multi-relaxation time lattice Boltzmann models is presented. We examine multi-relaxation time BGK collision operators that are constructed similarly to those for the MRT case, however, without explicitly moving into a moment space representation. The corresponding ‘moments’ are derived as left eigenvectors of said collision operator in velocity space. Consequently we can, in a representation independent of the chosen base velocity set, generate the conservation equations. We find a significant degree of freedom in the choice of the collision matrix and the associated basis which leaves the collision operator invariant. We explain why MRT implementations in the literature reproduce identical hydrodynamics despite being based on different orthogonalization relations. More importantly, however, we outline a minimal set of requirements on the moment base necessary to maintain the validity of the hydrodynamic equations. This is particularly useful in the context of position and time-dependent moments such as those used in the context of peculiar velocities and some implementations of fluctuations in a lattice-Boltzmann simulation.