1,026 research outputs found

    ISSM: Ice Sheet System Model

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    In order to have the capability to use satellite data from its own missions to inform future sea-level rise projections, JPL needed a full-fledged ice-sheet/iceshelf flow model, capable of modeling the mass balance of Antarctica and Greenland into the near future. ISSM was developed with such a goal in mind, as a massively parallelized, multi-purpose finite-element framework dedicated to ice-sheet modeling. ISSM features unstructured meshes (Tria in 2D, and Penta in 3D) along with corresponding finite elements for both types of meshes. Each finite element can carry out diagnostic, prognostic, transient, thermal 3D, surface, and bed slope simulations. Anisotropic meshing enables adaptation of meshes to a certain metric, and the 2D Shelfy-Stream, 3D Blatter/Pattyn, and 3D Full-Stokes formulations capture the bulk of the ice-flow physics. These elements can be coupled together, based on the Arlequin method, so that on a large scale model such as Antarctica, each type of finite element is used in the most efficient manner. For each finite element referenced above, ISSM implements an adjoint. This adjoint can be used to carry out model inversions of unknown model parameters, typically ice rheology and basal drag at the ice/bedrock interface, using a metric such as the observed InSAR surface velocity. This data assimilation capability is crucial to allow spinning up of ice flow models using available satellite data. ISSM relies on the PETSc library for its vectors, matrices, and solvers. This allows ISSM to run efficiently on any parallel platform, whether shared or distrib- ISSM: Ice Sheet System Model NASA's Jet Propulsion Laboratory, Pasadena, California uted. It can run on the largest clusters, and is fully scalable. This allows ISSM to tackle models the size of continents. ISSM is embedded into MATLAB and Python, both open scientific platforms. This improves its outreach within the science community. It is entirely written in C/C++, which gives it flexibility in its design, and the power/speed that C/C++ allows. ISSM is svn (subversion) hosted, on a JPL repository, to facilitate its development and maintenance. ISSM can also model propagation of rifts using contact mechanics and mesh splitting, and can interface to the Dakota software. To carry out sensitivity analysis, mesh partitioning algorithms are available, based on the Scotch, Chaco, and Metis partitioners that ensure equal area mesh partitions can be done, which are then usable for sampling and local reliability methods

    Medical bioremediation of age-related diseases

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    Catabolic insufficiency in humans leads to the gradual accumulation of a number of pathogenic compounds associated with age-related diseases, including atherosclerosis, Alzheimer's disease, and macular degeneration. Removal of these compounds is a widely researched therapeutic option, but the use of antibodies and endogenous human enzymes has failed to produce effective treatments, and may pose risks to cellular homeostasis. Another alternative is "medical bioremediation," the use of microbial enzymes to augment missing catabolic functions. The microbial genetic diversity in most natural environments provides a resource that can be mined for enzymes capable of degrading just about any energy-rich organic compound. This review discusses targets for biodegradation, the identification of candidate microbial enzymes, and enzyme-delivery methods

    The Influence of Individual Characteristics and the Work Environment on Varying Levels of Training Outcomes

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    This study tested a model in which pretraining self-efficacy and motivation were hypothesized to mediate the relationship between job involvement, organizational commitment, perceptions of the work environment, and training reactions and knowledge acquisition. It also proposed hierarchical relationships between levels of training effectiveness criteria. A series of analyses demonstrated support for the model. Future research should incorporate a multilevel framework and consider the multidimensional nature of training outcomes

    Exploiting tumor epigenetics to improve oncolytic virotherapy

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    Oncolytic viruses (OVs) comprise a versatile and multi-mechanistic therapeutic platform in the growing arsenal of anticancer biologics. These replicating therapeutics find favorable conditions in the tumor niche, characterized among others by increased metabolism, reduced anti-tumor/antiviral immunity, and disorganized vasculature. Through a self-amplification that is dependent on multiple cancer-specific defects, these agents exhibit remarkable tumor selectivity. With several OVs completing or entering Phase III clinical evaluation, their therapeutic potential as well as the challenges ahead are increasingly clear. One key hurdle is tumor heterogeneity, which results in variations in the ability of tumors to support productive infection by OVs and to induce adaptive anti-tumor immunity. To this end, mounting evidence suggests tumor epigenetics may play a key role. This review will focus on the epigenetic landscape of tumors and how it relates to OV infection. Therapeutic strategies aiming to exploit the epigenetic identity of tumors in order to improve OV therapy are also discussed

    Barriers, facilitators and views about next steps to implementing supports for evidence-informed decision-making in health systems: a qualitative study

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    Background: Mobilizing research evidence for daily decision-making is challenging for health system decision-makers. In a previous qualitative paper, we showed the current mix of supports that Canadian health-care organizations have in place and the ones that are perceived to be helpful to facilitate the use of research evidence in health system decision-making. Factors influencing the implementation of such supports remain poorly described in the literature. Identifying the barriers to and facilitators of different interventions is essential for implementation of effective, context-specific, supports for evidence-informed decision-making (EIDM) in health systems. The purpose of this study was to identify (a) barriers and facilitators to implementing supports for EIDM in Canadian health-care organizations, (b) views about emerging development of supports for EIDM, and (c) views about the priorities to bridge the gaps in the current mix of supports that these organizations have in place. Methods: This qualitative study was conducted in three types of health-care organizations (regional health authorities, hospitals, and primary care practices) in two Canadian provinces (Ontario and Quebec). Fifty-seven in-depth semi-structured telephone interviews were conducted with senior managers, library managers, and knowledge brokers from health-care organizations that have already undertaken strategic initiatives in knowledge translation. The interviews were taped, transcribed, and then analyzed thematically using NVivo 9 qualitative data analysis software. Results: Limited resources (i.e., money or staff), time constraints, and negative attitudes (or resistance) toward change were the most frequently identified barriers to implementing supports for EIDM. Genuine interest from health system decision-makers, notably their willingness to invest money and resources and to create a knowledge translation culture over time in health-care organizations, was the most frequently identified facilitator to implementing supports for EIDM. The most frequently cited views about emerging development of supports for EIDM were implementing accessible and efficient systems to support the use of research in decision-making (e.g., documentation and reporting tools, communication tools, and decision support tools) and developing and implementing an infrastructure or position where the accountability for encouraging knowledge use lies. The most frequently stated priorities for bridging the gaps in the current mix of supports that these organizations have in place were implementing technical infrastructures to support research use and to ensure access to research evidence and establishing formal or informal ties to researchers and knowledge brokers outside the organization who can assist in EIDM. Conclusions: These results provide insights on the type of practical implementation imperatives involved in supporting EIDM

    SHARED TEAM EXPERIENCES AND TEAM EFFECTIVENESS: UNPACKING THE CONTINGENT EFFECTS OF ENTRAINED RHYTHMS AND TASK CHARACTERISTICS

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    This study explores the conditions under which shared team task-specific (STTS) experiences in crew-based arrangements may negatively influence team effectiveness.We suggest that the entrained rhythms featured in social entrainment theory act as a dual-edged sword with the potential to generate complacency detriments in addition to the commonly cited synchronization benefits. We argue that the manifestation and influence of the countervailing forces (i.e., synchronization and complacency) on the STTS experience—team effectiveness relationship will depend on salient task characteristics (i.e., frequency and difficulty). More specifically, frequently performed tasks create conditions for complacency tomanifest (generating an inverted-U shaped relationship between STTS experience—team efficiency), whereas infrequently performed tasks do not (generating a positive, linear relationship). We further this distinction by layering on task difficulty that, we posit, acts to amplify the respective negative and positive consequences. Analyses of archival data from 8,236 surgeries performed over one year at a large hospital located in the southwestern region of the United States were consistent with our hypotheses and 30 semi-structured interviews with operating room personnel added richness and precision to our theory. Ancillary analyses on patient post-surgery recovery rate yielded additional insights. Implications and future directions are discussed

    SHARED TEAM EXPERIENCES AND TEAM EFFECTIVENESS: UNPACKING THE CONTINGENT EFFECTS OF ENTRAINED RHYTHMS AND TASK CHARACTERISTICS

    Get PDF
    This study explores the conditions under which shared team task-specific (STTS) experiences in crew-based arrangements may negatively influence team effectiveness.We suggest that the entrained rhythms featured in social entrainment theory act as a dual-edged sword with the potential to generate complacency detriments in addition to the commonly cited synchronization benefits. We argue that the manifestation and influence of the countervailing forces (i.e., synchronization and complacency) on the STTS experience—team effectiveness relationship will depend on salient task characteristics (i.e., frequency and difficulty). More specifically, frequently performed tasks create conditions for complacency tomanifest (generating an inverted-U shaped relationship between STTS experience—team efficiency), whereas infrequently performed tasks do not (generating a positive, linear relationship). We further this distinction by layering on task difficulty that, we posit, acts to amplify the respective negative and positive consequences. Analyses of archival data from 8,236 surgeries performed over one year at a large hospital located in the southwestern region of the United States were consistent with our hypotheses and 30 semi-structured interviews with operating room personnel added richness and precision to our theory. Ancillary analyses on patient post-surgery recovery rate yielded additional insights. Implications and future directions are discussed

    Escherichia coli ST8196 is a novel, locally evolved, and extensively drug resistant pathogenic lineage within the ST131 clonal complex

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    The H30Rx subclade of Escherichia coli ST131 is a clinically important, globally dispersed pathogenic lineage that typically displays resistance to fluoroquinolones and extended spectrum β-lactams. Isolates EC233 and EC234, variants of ST131-H30Rx with a novel sequence type (ST) 8196, isolated from unrelated patients presenting with bacteraemia at a Sydney Hospital in 2014 are characterised here. EC233 and EC234 are phylogroup B2, serotype O25:H4A, and resistant to ampicillin, amoxicillin, cefoxitin, ceftazidime, ceftriaxone, ciprofloxacin, norfloxacin and gentamicin and are likely clonal. Both harbour an IncFII_2 plasmid (pSPRC_Ec234-FII) that carries most of the resistance genes on an IS26 associated translocatable unit, two small plasmids and a novel IncI1 plasmid (pSPRC_Ec234-I). SNP-based phylogenetic analysis of the core genome of representatives within the ST131 clonal complex places both isolates in a subclade with three clinical Australian ST131-H30Rx clade-C isolates. A MrBayes phylogeny analysis of EC233 and EC234 indicates ST8196 share a most recent common ancestor with ST131-H30Rx strain EC70 isolated from the same hospital in 2013. Our study identified genomic hallmarks that define the ST131-H30Rx subclade in the ST8196 isolates and highlights a need for unbiased genomic surveillance approaches to identify novel high-risk MDR E. coli pathogens that impact healthcare facilities
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