2,651 research outputs found

    Retention Analysis Modeling for the Acquisition Workforce II

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    Acquisition Research Program Sponsored Report SeriesSponsored Acquisition Research & Technical ReportsTo support the modern warfighters tasked with increasing demands in a constantly changing global environment, it is imperative that the defense acquisition system continue to evolve to maintain its capability and flexibility. In this effort, growing a talented, experienced, and well-qualified civilian workforce will be vital. As part of this broad effort, the Section 809 Panel has recommended change to the DoD’s career management framework to grow and augment the workforce, and the DoD AWF Strategic Plan — FY 2016 – FY 2021 has emphasized efforts since 2010 to restore and restructure the AWF after a period of twenty years of shrinkage. This technical research report is the second in a proposed series of three linked studies to provide a cutting-edge modeling and simulation tool that leverages the increase in availability of AWF data and the large increases in computing power in the last decades. Building on the proof-of-concept model created as part of the first-year effort, we continue our development of a “Dynamic Retention Model (DRM)” designed from the ground-up for the AWF. Using a large personnel dataset of the acquisition workforce as well as a representative dataset of the civilian population from the Bureau of Labor Statistics, we estimate our DRM. DRM is a leading-edge technique that uses a powerful mathematical/econometric technique called dynamic programming. It takes a complex, multi-period problem (such as the lifetime labor market decisions of an acquisition worker) and breaks it down into simpler, one-period sub-problems in a recursive manner. Solving a single-period problem “nests” the future decisions that the worker will make, allowing the estimation and prediction of complex behavior in a surprisingly manageable framework. With estimates from the model, we simulate how various modifications in personnel policies, such as changes in salary structure and bonuses, would have affected the labor market decisions of the workforce. In particular, our model takes into account civilian positions the AWF may move into upon the decision to separate from DoD, allowing a more accurate prediction of the impact of monetary personnel policies, which must be evaluated in relation to what the worker could realistically earn in the civilian sector. In doing so, the model can help the AWF leadership in achieving the desired workforce size and structure. We conclude this report by expanding on possible extensions to enrich the model to provide yet more accurate estimation and richer simulations, including evaluating the potential impact of COVID-19 on the long-run career trajectory of the workforce.Approved for public release; distribution is unlimited.Approved for public release; distribution is unlimited

    Improving Loss Estimation for Woodframe Buildings. Volume 2: Appendices

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    This report documents Tasks 4.1 and 4.5 of the CUREE-Caltech Woodframe Project. It presents a theoretical and empirical methodology for creating probabilistic relationships between seismic shaking severity and physical damage and loss for buildings in general, and for woodframe buildings in particular. The methodology, called assembly-based vulnerability (ABV), is illustrated for 19 specific woodframe buildings of varying ages, sizes, configuration, quality of construction, and retrofit and redesign conditions. The study employs variations on four basic floorplans, called index buildings. These include a small house and a large house, a townhouse and an apartment building. The resulting seismic vulnerability functions give the probability distribution of repair cost as a function of instrumental ground-motion severity. These vulnerability functions are useful by themselves, and are also transformed to seismic fragility functions compatible with the HAZUS software. The methods and data employed here use well-accepted structural engineering techniques, laboratory test data and computer programs produced by Element 1 of the CUREE-Caltech Woodframe Project, other recently published research, and standard construction cost-estimating methods. While based on such well established principles, this report represents a substantially new contribution to the field of earthquake loss estimation. Its methodology is notable in that it calculates detailed structural response using nonlinear time-history structural analysis as opposed to the simplifying assumptions required by nonlinear pushover methods. It models physical damage at the level of individual building assemblies such as individual windows, segments of wall, etc., for which detailed laboratory testing is available, as opposed to two or three broad component categories that cannot be directly tested. And it explicitly models uncertainty in ground motion, structural response, component damageability, and contractor costs. Consequently, a very detailed, verifiable, probabilistic picture of physical performance and repair cost is produced, capable of informing a variety of decisions regarding seismic retrofit, code development, code enforcement, performance-based design for above-code applications, and insurance practices

    Superoxide dismutase downregulation in osteoarthritis progression and end-stage disease

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    Oxidative stress is proposed as an important factor in osteoarthritis (OA). To investigate the expression of the three superoxide dismutase (SOD) antioxidant enzymes in OA. SOD expression was determined by real-time PCR and immunohistochemistry using human femoral head cartilage. SOD2 expression in Dunkin–Hartley guinea pig knee articular cartilage was determined by immunohistochemistry. The DNA methylation status of the SOD2 promoter was determined using bisulphite sequencing. RNA interference was used to determine the consequence of SOD2 depletion on the levels of reactive oxygen species (ROS) using MitoSOX and collagenases, matrix metalloproteinase 1 (MMP-1) and MMP-13, gene expression. All three SOD were abundantly expressed in human cartilage but were markedly downregulated in end-stage OA cartilage, especially SOD2. In the Dunkin–Hartley guinea pig spontaneous OA model, SOD2 expression was decreased in the medial tibial condyle cartilage before, and after, the development of OA-like lesions. The SOD2 promoter had significant DNA methylation alterations in OA cartilage. Depletion of SOD2 in chondrocytes increased ROS but decreased collagenase expression. This is the first comprehensive expression profile of all SOD genes in cartilage and, importantly, using an animal model, it has been shown that a reduction in SOD2 is associated with the earliest stages of OA. A decrease in SOD2 was found to be associated with an increase in ROS but a reduction of collagenase gene expression, demonstrating the complexities of ROS function

    Rationalizing the Activity of an “Artificial Diels-Alderase”: Establishing Efficient and Accurate Protocols for Calculating Supramolecular Catalysis

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    Self-assembled cages have emerged as novel platforms to explore bio-inspired catalysis. While many different size and shape supramolecular structures are now readily accessible, only a few are known to accelerate chemical reactions under sub-stoichiometric conditions. These limited examples point to a poor understanding of cage catalysis in general, limiting the ability to design new systems. Here we show that a simple and efficient density functional theory-based methodology, in-formed by explicitly solvated molecular dynamics and coupled-cluster calculations is sufficient to accurately reproduce experimental guest binding affinities (MAD = 1.9 kcal mol-1) and identify the catalytic Diels-Alder proficiencies (>80 % accuracy) of two homologous Pd2L4 metallocages with a variety of substrates. This analysis reveals how subtle structural differences in the cage framework affect binding and catalysis. These effects manifest in a smaller distortion and more favorable interaction energy for the catalytic cage compared to the inactive structure. This study gives a detailed insight that would otherwise be difficult to obtain from experiments, providing new opportunities in the design catalytically active supramolecular cages

    Exploring the Role of Contextual Integrity in Electronic Medical Record (EMR) System Workaround Decisions: An Information Security and Privacy Perspective

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    Many healthcare providers in the US are seeking increased efficiency and effectiveness by rapidly adopting information technology (IT) solutions such as electronic medical record (EMR) systems. Legislation such as the Health Information Technology for Economic and Clinical Health Act (HITECH), which codified the adoption and “meaningful use” of electronic records in the US, has further spurred the industry-wide adoption of EMR. However, despite what are often large investments in EMR, studies indicate that the healthcare industry maintains a culture of system workarounds. Though perhaps not uncommon, the creation of informal workflows among healthcare workers is problematic for assuring information security and patient privacy, particularly when involving decisions of information management (e.g., information storage, retrieval, and/or transmission). Drawing on the framework of contextual integrity, we assert that one can often explain workarounds involving information transmissions in terms of trade-offs informed by context-specific informational norms. We surveyed healthcare workers and analyzed their willingness to engage in a series of EMR workaround scenarios. Our results indicate that contextual integrity provides a useful framework for understanding information transmission and workaround decisions in the health sector. Armed with these findings, managers and system designers should be better able to anticipate healthcare workers’ information transmission principles (e.g., privacy norms) and workaround patterns (e.g., usage norms). We present our findings and discuss their significance for research and practice

    Computational Modeling of Supramolecular Metallo-organic Cages-Challenges and Opportunities

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    [Image: see text] Self-assembled metallo-organic cages have emerged as promising biomimetic platforms that can encapsulate whole substrates akin to an enzyme active site. Extensive experimental work has enabled access to a variety of structures, with a few notable examples showing catalytic behavior. However, computational investigations of metallo-organic cages are scarce, not least due to the challenges associated with their modeling and the lack of accurate and efficient protocols to evaluate these systems. In this review, we discuss key molecular principles governing the design of functional metallo-organic cages, from the assembly of building blocks through binding and catalysis. For each of these processes, computational protocols will be reviewed, considering their inherent strengths and weaknesses. We will demonstrate that while each approach may have its own specific pitfalls, they can be a powerful tool for rationalizing experimental observables and to guide synthetic efforts. To illustrate this point, we present several examples where modeling has helped to elucidate fundamental principles behind molecular recognition and reactivity. We highlight the importance of combining computational and experimental efforts to speed up supramolecular catalyst design while reducing time and resources

    Instability of a four-dimensional de Sitter black hole with a conformally coupled scalar field

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    We study the stability of new neutral and electrically charged four-dimensional black hole solutions of Einstein's equations with a positive cosmological constant and conformally coupled scalar field. The neutral black holes are always unstable. The charged black holes are also shown analytically to be unstable for the vast majority of the parameter space of solutions, and we argue using numerical techniques that the configurations corresponding to the remainder of the parameter space are also unstable.Comment: revtex4, 8 pages, 4 figures, minor changes, accepted for publication in Phys. Rev.
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