572 research outputs found

    Automated schema matching techniques: an exploratory study

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    Manual schema matching is a problem for many database applications that use multiple data sources including data warehousing and e-commerce applications. Current research attempts to address this problem by developing algorithms to automate aspects of the schema-matching task. In this paper, an approach using an external dictionary facilitates automated discovery of the semantic meaning of database schema terms. An experimental study was conducted to evaluate the performance and accuracy of five schema-matching techniques with the proposed approach, called SemMA. The proposed approach and results are compared with two existing semi-automated schema-matching approaches and suggestions for future research are made

    Enrolment and Retention in Adult Basic Education Programs Some Theoretical Implications of a National Study Follow-up Study

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    Using the findings of a national follow-up study (n=338), this paper discusses the factors associated with nonenrolment and dropping out of literacy and upgrading programs. In addition to illuminating the complexity of low enrolment and high drop out rates, the paper moves toward a more integrated understanding of the structural and agency-related explanations for these patterns

    Religion, Politics, and the Virgin Queen

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    This paper will analyze Elizabeth I’s political style and the effects on it by both religion and influential men in the “Virgin Queen’s” council. Her relationships with Mary Tudor and Mary, Queen of Scots, and their religion, affected her politics and how her Protestantism clashed with these two Catholic monarchs. Comparing Mary Tudor’s forceful assertion of Catholicism in her reign to Elizabeth’s approach to Protestant dissenters will demon­strate religion’s role in their politics. I will also analyze the aspect of religion on Elizabeth’s and Mary Stuart’s dual claims to the English throne. Elizabeth Jenkins’s work, Elizabeth the Great, explores all aspects of Elizabeth’s life but focuses on her reign as queen and the treatment of Catholics under her now Protestant reign as compared to Mary’s treatment of dissenters. From the very beginning of her reign, Elizabeth was viewed as illegitimate by some English Catholics as well as Scottish Catholics. Many believed that Mary Stuart, Queen of Scots, had the legitimate claim to the English throne rather than Elizabeth. Anne McLaren’s article continues to explore their relationship. Allison Heisch’s article discusses the role of men and the patriarchy in Elizabeth’s rule and the perpet­uation of the image of the “Virgin Queen.” This paper will ultimately analyze the role of religion and Elizabeth’s relationship with Mary Tudor and Mary Stuart as well as the perpetuation of the “Virgin Queen” and the role of men in attempting to influence Elizabeth and her reign

    Multilayered specification of the T-cell lineage fate

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    T-cell development from stem cells has provided a highly accessible and detailed view of the regulatory processes that can go into the choice of a cell fate in a postembryonic, stem cell-based system. But it has been a view from the outside. The problems in understanding the regulatory basis for this lineage choice begin with the fact that too many transcription factors are needed to provide crucial input: without any one of them, T-cell development fails. Furthermore, almost all the factors known to provide crucial functions during the climax of T-lineage commitment itself are also vital for earlier functions that establish the pool of multilineage precursors that would normally feed into the T-cell specification process. When the regulatory genes that encode them are mutated, the confounding effects on earlier stages make it difficult to dissect T-cell specification genetically. Yet both the positive and the negative regulatory events involved in the choice of a T-cell fate are actually a mosaic of distinct functions. New evidence has emerged recently that finally provides a way to separate the major components that fit together to drive this process. Here, we review insights into T-cell specification and commitment that emerge from a combination of molecular, cellular, and systems biology approaches. The results reveal the regulatory structure underlying this lineage decision

    An Early T Cell Lineage Commitment Checkpoint Dependent on the Transcription Factor Bcl11b

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    The identities of the regulators that mediate commitment of hematopoietic precursors to the T lymphocyte lineage have been unknown. The last stage of T lineage commitment in vivo involves mechanisms to suppress natural killer cell potential, to suppress myeloid and dendritic cell potential, and to silence the stem cell or progenitor cell regulatory functions that initially provide T cell receptor–independent self-renewal capability. The zinc finger transcription factor Bcl11b is T cell–specific in expression among hematopoietic cell types and is first expressed in precursors immediately before T lineage commitment. We found that Bcl11b is necessary for T lineage commitment in mice and is specifically required both to repress natural killer cell–associated genes and to down-regulate a battery of stem cell or progenitor cell genes at the pivotal stage of commitment

    The Impact of Pharmacogenomics on Chemotherapeutic Drug Development and Use

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    Cancer therapy is largely dependent on general treatment guidelines, and patients undergoing chemotherapy often experience treatment failure with standard drugs. The development of individualized drug therapy through pharmacogenomics has the potential to enhance chemotherapy regimen selection and improve patient outcomes. Antineoplastic agents such as cetuximab and trastuzumab are effective in treating cancers possessing specific genetic biomarker characteristics. Patients need to undergo genetic testing before these agents are administered to ensure appropriate use. Cetuximab has been shown to improve outcomes in metastatic colorectal cancers and head and neck squamous cell carcinomas positive for EGFR. Trastuzumab has shown benefit in human epidermal growth factor receptor 2 (HER2) overexpressing cancers affecting the breast tissue and gastrointestinal tract. High costs associated with the development of targeted drugs and a lack of clinical studies exploring the effects genetic variations can have on drug therapy limit implementation of pharmacogenomics into routine practice. As drug therapy experts, pharmacists need to be aware of advances in the field of pharmacogenomics and facilitate the use of this new class of personalized drugs

    Atmospheric chemistry of CH\u3csub\u3e3\u3c/sub\u3eCHO: the hydrolysis of CH\u3csub\u3e3\u3c/sub\u3eCHO catalyzed by H\u3csub\u3e2\u3c/sub\u3eSO\u3csub\u3e4\u3c/sub\u3e

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    Elucidating atmospheric oxidation mechanisms and the reaction kinetics of atmospheric compounds is of great importance and necessary for atmospheric modeling and the understanding of the formation of atmospheric organic aerosols. While the hydrolysis of aldehydes has been detected in the presence of sulfuric acid, the reaction mechanism and kinetics remain unclear. Herein, we use electronic structure methods with CCSD(T)/CBS accuracy and canonical variational transition state theory combined with small-curvature tunneling to study the reaction mechanism and kinetics of the hydrolysis of CH3CHO. The calculated results show that the hydrolysis of CH3CHO needs to overcome an energy barrier of 37.21 kcal mol−1, while the energy barrier is decreased to −9.79 kcal mol−1 with a sulfuric acid catalyst. In addition, the calculated kinetic results show that the H2SO4⋯H2O + CH3CHO reaction is faster than H2SO4 + CH3CHO⋯H2O. Additionally, the H2SO4⋯H2O + CH3CHO reaction can play an important role in the sink of CH3CHO below 260 K occurring during the night period when OH, H2SO4, and H2O concentrations are 104, 108, and 1017 molecules cm−3, respectively, because it can compete well with the CH3CHO + OH reaction. There are wide implications in atmospheric chemistry from these findings because of the potential importance of the catalytic effect of H2SO4 on the hydrolysis of CH3CHO in the atmosphere and in the formation of secondary organic aerosols

    Autonomous power expert system

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    The Autonomous Power Expert (APEX) system was designed to monitor and diagnose fault conditions that occur within the Space Station Freedom Electrical Power System (SSF/EPS) Testbed. APEX is designed to interface with SSF/EPS testbed power management controllers to provide enhanced autonomous operation and control capability. The APEX architecture consists of three components: (1) a rule-based expert system, (2) a testbed data acquisition interface, and (3) a power scheduler interface. Fault detection, fault isolation, justification of probable causes, recommended actions, and incipient fault analysis are the main functions of the expert system component. The data acquisition component requests and receives pertinent parametric values from the EPS testbed and asserts the values into a knowledge base. Power load profile information is obtained from a remote scheduler through the power scheduler interface component. The current APEX design and development work is discussed. Operation and use of APEX by way of the user interface screens is also covered

    Why are plant–soil feedbacks so unpredictable, and what to do about it?

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    1.The study of feedbacks between plants and soils (plant‐soil feedbacks; PSFs) is receiving increased attention. However, PSFs have been mostly studied in isolation of abiotic and biotic drivers that could affect their strength and direction. This is problematic because it has led to limited predictive power of PSFs in ‘the real world’, leaving large knowledge gaps in our ability to predict how PSFs contribute to ecosystem processes and functions. 2.Here, we present a synthetic framework to elucidate how abiotic and biotic drivers affect PSFs. We focus on two key abiotic drivers (temperature and soil moisture) and two key biotic drivers (aboveground plant consumers and belowground top‐down control of pathogens and mutualists). We focus on these factors because they are known drivers of plants and soil organisms and the ecosystem processes they control, and hence would be expected to strongly influence PSFs. 3.Our framework describes the proposed mechanisms behind these drivers and explores their effects on PSFs. We demonstrate the impacts of these drivers using the fast‐ to slow‐growing plant economics spectrum. We use this well‐established paradigm because plants on opposite ends of this spectrum differ in their relationships with soil biota and have developed contrasting strategies to cope with abiotic and biotic environmental conditions. 4.Finally, we present suggestions for improved experimental designs and scientific inference that will capture and elucidate the influence of above‐ and belowground drivers on PSFs. By establishing the role of abiotic and biotic drivers of PSFs, we will be able to make more robust predictions of how PSFs impact on ecosystem function
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