729 research outputs found

    On the Effect of Quantum Interaction Distance on Quantum Addition Circuits

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    We investigate the theoretical limits of the effect of the quantum interaction distance on the speed of exact quantum addition circuits. For this study, we exploit graph embedding for quantum circuit analysis. We study a logical mapping of qubits and gates of any Ω(log⁥n)\Omega(\log n)-depth quantum adder circuit for two nn-qubit registers onto a practical architecture, which limits interaction distance to the nearest neighbors only and supports only one- and two-qubit logical gates. Unfortunately, on the chosen kk-dimensional practical architecture, we prove that the depth lower bound of any exact quantum addition circuits is no longer Ω(log⁥n)\Omega(\log {n}), but Ω(nk)\Omega(\sqrt[k]{n}). This result, the first application of graph embedding to quantum circuits and devices, provides a new tool for compiler development, emphasizes the impact of quantum computer architecture on performance, and acts as a cautionary note when evaluating the time performance of quantum algorithms.Comment: accepted for ACM Journal on Emerging Technologies in Computing System

    Quantum Estimation of Parameters of Classical Spacetimes

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    We describe a quantum limit to measurement of classical spacetimes. Specifically, we formulate a quantum Cramer-Rao lower bound for estimating the single parameter in any one-parameter family of spacetime metrics. We employ the locally covariant formulation of quantum field theory in curved spacetime, which allows for a manifestly background-independent derivation. The result is an uncertainty relation that applies to all globally hyperbolic spacetimes. Among other examples, we apply our method to detection of gravitational waves using the electromagnetic field as a probe, as in laser-interferometric gravitational-wave detectors. Other applications are discussed, from terrestrial gravimetry to cosmology.Comment: 23 pages. This article supersedes arXiv:1108.522

    D-BAS - A dialog-based online argumentation system

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    In this paper, we present D-BAS, a dialog-based online argumentation system, tailored to support e-participation processes. The main idea of D-BAS is to let users exchange proposals and arguments with each other in the form of a timeshifted dialog where arguments are presented and acted upon one-at-a-time. We highlight the key research challenges that needed to be addressed in order to realize such a system, provide solutions for those challenges, report on a full scale implementation of D-BAS and summarize the findings from a real world e-participation process, where D-BAS provided the infrastructure for online argumentation

    The nitrogen legacy: emerging evidence of nitrogen accumulation in anthropogenic landscapes

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    Watershed and global-scale nitrogen (N) budgets indicate that the majority of the N surplus in anthropogenic landscapes does not reach the coastal oceans. While there is general consensus that this \u27missing\u27 N either exits the landscape via denitrification or is retained within watersheds as nitrate or organic N, the relative magnitudes of these pools and fluxes are subject to considerable uncertainty. Our study, for the first time, provides direct, large-scale evidence of N accumulation in the root zones of agricultural soils that may account for much of the \u27missing N\u27 identified in mass balance studies. We analyzed long-term soil data (1957–2010) from 2069 sites throughout the Mississippi River Basin (MRB) to reveal N accumulation in cropland of 25–70 kg ha−1 yr−1, a total of 3.8 ± 1.8 Mt yr−1 at the watershed scale. We then developed a simple modeling framework to capture N depletion and accumulation dynamics under intensive agriculture. Using the model, we show that the observed accumulation of soil organic N (SON) in the MRB over a 30 year period (142 Tg N) would lead to a biogeochemical lag time of 35 years for 99% of legacy SON, even with complete cessation of fertilizer application. By demonstrating that agricultural soils can act as a net N sink, the present work makes a critical contribution towards the closing of watershed N budgets

    Fatalistic Beliefs and Completion of the HPV Vaccination Series Among a Sample of Young Appalachian Kentucky Women

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    PURPOSE: Uptake and completion of the 3-dose human papillomavirus (HPV) vaccine is important for the primary prevention of cervical cancer. However, HPV vaccination rates among adolescent females and young women remain low in certain geographic areas of the United States, including Appalachia. Although greater fatalistic beliefs have been previously associated with lower rates of preventive cancer behaviors among adults, little research exists on the impact of fatalism on HPV vaccination behaviors, especially among younger individuals. Therefore, the purpose of this study was to examine the association between fatalistic beliefs and completion of the full HPV vaccine series among young women, ages 18-26, in Appalachian Kentucky. RESULTS: Data from this study were from a baseline survey completed by 344 women randomized into a communication intervention trial focused on increasing adherence to the 3-dose HPV vaccine series. Principal components analysis was used to construct 2 fatalism-related subscales from 8 survey questions. FINDINGS: In a controlled analysis, 1 subscale-- lack of control over cancer --was significantly associated with not completing the full HPV vaccine series. In a rural area that experiences higher rates of cervical cancer, poverty, limited access to health care, and negative cancer-related attitudes and experiences, fatalism may be common, even among young people. CONCLUSION: Future educational and interventional research addressing fatalistic beliefs in a culturally sensitive manner may be warranted to improve HPV vaccination behaviors and impact cancer disparities among Appalachian women

    Novel Report of Expression and Function of CD97 in Malignant Gliomas: Correlation With Wilms Tumor 1 Expression and Glioma Cell Invasiveness Laboratory investigation

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    Object. The Wilms tumor 1 (WT1) protein—a developmentally regulated transcription factor—is aberrantly expressed in gliomas and promotes their malignant phenotype. However, little is known about the molecular allies that help it mediate its oncogenic functions in glioma cells. Methods. The authors used short interfering RNA (siRNA) to suppress WT1 expression in glioblastoma (GBM) cells and evaluated the effect of this on GBM cell invasiveness. Gene expression analysis was then used to identify the candidate genes that were altered as a result of WT1 silencing. One candidate target, CD97, was then selected for further investigation into its role by suppressing its expression using siRNA silencing, followed by proliferation and invasion assays. Results. WT1 levels were reliably and reproducibly suppressed by siRNA application. This resulted in a significant decrease in cellular invasiveness. Microarray analyses identified the gene products that were consistently downregulated (27) and upregulated (11) with WT1 silencing. Of these, CD97 expression was consistently suppressed across the 3 different GBM cell lines studied and was found on further investigation to significantly impact GBM cell invasiveness. Conclusions. Although CD97 expression in gliomas has not been described previously, we conclude that the possible upregulation of CD97 mediated by WT1 promotes cellular invasiveness—one of the most characteristic and challenging aspects of glial tumor cells. Further studies are needed to clarify the nature of this regulation and its impact, as CD97 could represent a novel target for antiglioma therapies

    A procedure to characterize geographic distributions of rare disorders in cohorts

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    <p>Abstract</p> <p>Background</p> <p>Individual point data can be analyzed against an entire cohort instead of only sampled controls to accurately picture the geographic distribution of populations at risk for low prevalence diseases. Analyzed as individual points, many smaller clusters with high relative risks (RR) and low empirical p values are indistinguishable from a random distribution. When points are aggregated into areal units, small clusters may result in a larger cluster with a low RR or be lost if divided into pieces included in units of larger populations that show no increased prevalence. Previous simulation studies showed lowered validity of spatial scan tests for true clusters with low RR. Using simulations, this study explored the effects of low cluster RR and areal unit size on local area clustering test (LACT) results, proposing a procedure to improve accuracy of cohort spatial analysis for rare events.</p> <p>Results</p> <p>Our simulations demonstrated the relationship of true RR to observed RR and p values with various, randomly located, cluster shapes, areal unit sizes and scanning window shapes in a diverse population distribution. Clusters with RR < 1.7 had elevated observed RRs and high p values.</p> <p>We propose a cluster identification procedure that applies parallel multiple LACTs, one on point data and three on two distinct sets of areal units created with varying population parameters that minimize the range of population sizes among units. By accepting only clusters identified by all LACTs, having a minimum population size, a minimum relative risk and a maximum p value, this procedure improves the specificity achieved by any one of these tests alone on a cohort study of low prevalence data while retaining sensitivity for small clusters. The procedure is demonstrated on two study regions, each with a five-year cohort of births and cases of a rare developmental disorder.</p> <p>Conclusion</p> <p>For truly exploratory research on a rare disorder, false positive clusters can cause costly diverted research efforts. By limiting false positives, this procedure identifies 'crude' clusters that can then be analyzed for known demographic risk factors to focus exploration for geographically-based environmental exposure on areas of otherwise unexplained raised incidence.</p

    Novel Report of Expression and Function of CD97 in Malignant Gliomas: Correlation With Wilms Tumor 1 Expression and Glioma Cell Invasiveness Laboratory investigation

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    Object. The Wilms tumor 1 (WT1) protein—a developmentally regulated transcription factor—is aberrantly expressed in gliomas and promotes their malignant phenotype. However, little is known about the molecular allies that help it mediate its oncogenic functions in glioma cells. Methods. The authors used short interfering RNA (siRNA) to suppress WT1 expression in glioblastoma (GBM) cells and evaluated the effect of this on GBM cell invasiveness. Gene expression analysis was then used to identify the candidate genes that were altered as a result of WT1 silencing. One candidate target, CD97, was then selected for further investigation into its role by suppressing its expression using siRNA silencing, followed by proliferation and invasion assays. Results. WT1 levels were reliably and reproducibly suppressed by siRNA application. This resulted in a significant decrease in cellular invasiveness. Microarray analyses identified the gene products that were consistently downregulated (27) and upregulated (11) with WT1 silencing. Of these, CD97 expression was consistently suppressed across the 3 different GBM cell lines studied and was found on further investigation to significantly impact GBM cell invasiveness. Conclusions. Although CD97 expression in gliomas has not been described previously, we conclude that the possible upregulation of CD97 mediated by WT1 promotes cellular invasiveness—one of the most characteristic and challenging aspects of glial tumor cells. Further studies are needed to clarify the nature of this regulation and its impact, as CD97 could represent a novel target for antiglioma therapies

    Spiritual Directors and Clinical Psychologists: A Comparison of Mental Health and Spiritual Values (Taken from Chapter 3 of Spiritual Formation, Counseling, and Psychotherapy)

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    We surveyed a total of 315 spiritual directors, psychologist members of the Christian Association for Psychological Studies (CAPS), and psychologist members of the American Psychological Association (APA) to determine their respective values on ten mental health themes derives from Jensen and Bergin (1988), and three spirituality scales drawn from the writings of John of the Cross. All three groups endorsed the value of expressing feelings, personal autonomy and maturity, and integrating work and leisure. CAPS psychologists and spiritual directors endorsed more than APA psychologists the values of spirituality, forgiveness, and the three John of the Cross scales. Spiritual directors reported greater endorsement of the self-awareness and growth theme then did psychodynamic psychologists who, in turn, reported greater endorsement than cognitive-behavioral psychologists. The results are examined in light of the pre-Enlightenment paradigm and value system in which spiritual direction and Christian theology are rooted
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