293 research outputs found

    The USNO/NRL Green Bank interferometer program

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    Application of the connected-element radio interferometer of the National Radio Astronomy Observation in Green Bank, West Virginia to the determination of improved source coordinates, astronomical constants, and variations in Earth rotation parameters is discussed. It is concluded that because of the brevity and discontinuity of the data so far no reliable conclusions regarding the accuracy of the data can be drawn

    Knowledge Transfer and Teaching Public Administration: the Academy Model

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    Since the beginnings of Public Administration in the US and its accompanying education in other parts of the world, government and policy have become more complex. The education in Public Administration created a professional pathway to public service. The addition of education to Public Administration came out of the Progressive Movement in the United States to make knowledge in Public Administration more important in the face of corruption brought on by patronage appointments. When nonprofits became part the US public sector as elsewhere along with nonprofit healthcare, the complexity expanded enormously, requiring professionals to know more in what has become a multidisciplinary field of study. Given the diversity and complexity of the public sector and the need for Public Administration to embrace more knowledge from many disciplines, it stands to reason that an earlier start on the education portion of Public Administration or a pathway would be beneficial. A model of early Public Administration knowledge transfer is described and illustrated below. The Academy described is based on the US career pathways and high school academies as part of the school to work educational movement. The success of the combination of these two areas will also be pointed out in the academy described. Translation of lessons learned from the Acdemy to Europe and Asia are also considered

    Exceptional Larval Morphology of Nine Species of the Anastrepha mucronota Species Group (Diptera: Tephritidae)

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    Anastrepha is the most diverse and economically important genus of Tephritidae in the American tropics and subtropics. The striking morphology of the third instars of Anastrepha caballeroi Norrbom, Anastrepha crebra Stone, Anastrepha haplacantha Norrbom & Korytkowski, Anastrepha korytkowskii Norrbom, Anastrepha nolazcoae Norrbom & Korytkowski, and three newly discovered and as yet formally unnamed species (Anastrepha sp. Peru-82, Anastrepha sp. nr. protuberans, and Anastrepha sp. Sur-16), and the more typical morphology of Anastrepha aphelocentema Stone, are described using light and scanning electron microscopy. To contribute to a better understanding of the interspecific and intraspecific variation among species in the mucronota species group and facilitate phylogenetic studies, we integrate molecular and morphological techniques to confirm the identity and describe third instars. Larva-adult associations and the identification of described larvae were confirmed using DNA barcodes. We provide diagnostic characters to distinguish larvae among these nine species of the mucronota group and separate them from those of the 29 other Anastrepha species previously described. We introduce the vertical comb-like processes on the oral margin as a novel character, and the unusual character states, including position and shape of the preoral lobe, and dentate or fringed posterior margins of the oral ridges and accessory plates. Our comparative morphology concurs with most previously inferred phylogenetic relationships within the mucronota group

    Experimental Evidence of Time Delay Induced Death in Coupled Limit Cycle Oscillators

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    Experimental observations of time delay induced amplitude death in a pair of coupled nonlinear electronic circuits that are individually capable of exhibiting limit cycle oscillations are described. In particular, the existence of multiply connected death islands in the parameter space of the coupling strength and the time delay parameter for coupled identical oscillators is established. The existence of such regions was predicted earlier on theoretical grounds in [Phys. Rev. Lett. 80, 5109 (1998); Physica 129D, 15 (1999)]. The experiments also reveal the occurrence of multiple frequency states, frequency suppression of oscillations with increased time delay and the onset of both in-phase and anti-phase collective oscillations.Comment: 4 aps formatted RevTeX pages; 6 figures; to appear in Phys. Rev. Let

    Hypomethylation of the IL17RC promoter in peripheral blood leukocytes is not a hallmark of age-related macular degeneration

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    This is an open-access article distributed under the terms of the Creative Commons Attribution-NonCommercial-No Derivative Works License, which permits non-commercial use, distribution, and reproduction in any medium, provided the original author and source are credited.Age-related macular degeneration (AMD) is a leading cause of visual impairment worldwide. Aberrant DNA methylation within the promoter of IL17RC in peripheral blood mononuclear cells has recently been reported in AMD. To validate this association, we examined DNA methylation of the IL17RC promoter in peripheral blood. First, we used Illumina Human Methylation450 Bead Arrays, a widely accepted platform for measuring global DNA methylation. Second, methylation status at multiple sites within the IL17RC promoter was determined by bisulfite pyrosequencing in two cohorts. Third, a methylation-sensitive quantitative PCR-based assay was performed on a subset of samples. In contrast to previous findings, we did not find evidence of differential methylation between AMD cases and age-matched controls. We conclude that hypomethylation within the IL17RC gene promoter in peripheral blood is not suitable for use as a clinical biomarker of AMD. This study highlights the need for considerable replication of epigenetic association studies prior to clinical application

    CFH haplotypes without the Y402H coding variant show strong association with susceptibility to age-related macular degeneration

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    In developed countries, age-related macular degeneration is a common cause of blindness in the elderly. A common polymorphism, encoding the sequence variation Y402H in complement factor H (CFH), has been strongly associated with disease susceptibility. Here, we examined 84 polymorphisms in and around CFH in 726 affected individuals (including 544 unrelated individuals) and 268 unrelated controls. In this sample, 20 of these polymorphisms showed stronger association with disease susceptibility than the Y402H variant. Further, no single polymorphism could account for the contribution of the CFH locus to disease susceptibility. Instead, multiple polymorphisms defined a set of four common haplotypes (of which two were associated with disease susceptibility and two seemed to be protective) and multiple rare haplotypes (associated with increased susceptibility in aggregate). Our results suggest that there are multiple disease susceptibility alleles in the region and that noncoding CFH variants play a role in disease susceptibility

    Classifying and scoring of molecules with the NGN: new datasets, significance tests, and generalization

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    <p>Abstract</p> <p/> <p>This paper demonstrates how a Neural Grammar Network learns to classify and score molecules for a variety of tasks in chemistry and toxicology. In addition to a more detailed analysis on datasets previously studied, we introduce three new datasets (BBB, FXa, and toxicology) to show the generality of the approach. A new experimental methodology is developed and applied to both the new datasets as well as previously studied datasets. This methodology is rigorous and statistically grounded, and ultimately culminates in a Wilcoxon significance test that proves the effectiveness of the system. We further include a complete generalization of the specific technique to arbitrary grammars and datasets using a mathematical abstraction that allows researchers in different domains to apply the method to their own work.</p> <p>Background</p> <p>Our work can be viewed as an alternative to existing methods to solve the quantitative structure-activity relationship (QSAR) problem. To this end, we review a number approaches both from a methodological and also a performance perspective. In addition to these approaches, we also examined a number of chemical properties that can be used by generic classifier systems, such as feed-forward artificial neural networks. In studying these approaches, we identified a set of interesting benchmark problem sets to which many of the above approaches had been applied. These included: ACE, AChE, AR, BBB, BZR, Cox2, DHFR, ER, FXa, GPB, Therm, and Thr. Finally, we developed our own benchmark set by collecting data on toxicology.</p> <p>Results</p> <p>Our results show that our system performs better than, or comparatively to, the existing methods over a broad range of problem types. Our method does not require the expert knowledge that is necessary to apply the other methods to novel problems.</p> <p>Conclusions</p> <p>We conclude that our success is due to the ability of our system to: 1) encode molecules losslessly before presentation to the learning system, and 2) leverage the design of molecular description languages to facilitate the identification of relevant structural attributes of the molecules over different problem domains.</p

    Improvement in the Reproducibility and Accuracy of DNA Microarray Quantification by Optimizing Hybridization Conditions

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    BACKGROUND: DNA microarrays, which have been increasingly used to monitor mRNA transcripts at a global level, can provide detailed insight into cellular processes involved in response to drugs and toxins. This is leading to new understandings of signaling networks that operate in the cell, and the molecular basis of diseases. Custom printed oligonucleotide arrays have proven to be an effective way to facilitate the applications of DNA microarray technology. A successful microarray experiment, however, involves many steps: well-designed oligonucleotide probes, printing, RNA extraction and labeling, hybridization, and imaging. Optimization is essential to generate reliable microarray data. RESULTS: Hybridization and washing steps are crucial for a successful microarray experiment. By following the hybridization and washing conditions recommended by an oligonucleotide provider, it was found that the expression ratios were compressed greater than expected and data analysis revealed a high degree of non-specific binding. A series of experiments was conducted using rat mixed tissue RNA reference material (MTRRM) and other RNA samples to optimize the hybridization and washing conditions. The optimized hybridization and washing conditions greatly reduced the non-specific binding and improved the accuracy of spot intensity measurements. CONCLUSION: The results from the optimized hybridization and washing conditions greatly improved the reproducibility and accuracy of expression ratios. These experiments also suggested the importance of probe designs using better bioinformatics approaches and the need for common reference RNA samples for platform performance evaluation in order to fulfill the potential of DNA microarray technology

    Worldwide Argus II implantation: recommendations to optimize patient outcomes

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    Abstract Background A position paper based on the collective experiences of Argus II Retinal Prosthesis System investigators to review strategies to optimize outcomes in patients with retinitis pigmentosa undergoing retinal prosthesis implantation. Methods Retinal surgeons, device programmers, and rehabilitation specialists from Europe, Canada, Middle East, and the United States were convened to the first international Argus II Investigator Meeting held in Ann Arbor, MI in March 2015. The recommendations from the collective experiences were collected. Factors associated with successful outcomes were determined. Results Factors leading to successful outcomes begin with appropriate patient selection, expectation counseling, and preoperative retinal assessment. Challenges to surgical implantation include presence of staphyloma and inadequate Tenon’s capsule or conjunctiva. Modified surgical technique may reduce risks of complications such as hypotony and conjunctival erosion. Rehabilitation efforts and correlation with validated outcome measures following implantation are critical. Conclusions Bringing together Argus II investigators allowed the identification of strategies to optimize patient outcomes. Establishing an on-line collaborative network will foster coordinated research efforts to advance outcome assessment and rehabilitation strategies.http://deepblue.lib.umich.edu/bitstream/2027.42/134581/1/12886_2016_Article_225.pd
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