313 research outputs found

    Quadrature noise in light propagating through a cold 87Rb atomic gas

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    We report on the study of the noise properties of laser light propagating through a cold 87Rb atomic sample held in a magneto-optical trap. The laser is tuned around the Fg = 2 \rightarrow Fe = 1, 2 D1 transitions of 87Rb. We observe quadrature-dependent noise in the light signal, an indication that it may be possible to produce squeezed states of light. We measure the minimum and maximum phase-dependent noise as a function of detuning and compare these results to theoretical predictions to explore the best conditions for light squeezing using cold atomic Rb

    The 70 Percent Solution Summary Report

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    This summary report offers a different vision of how educators, employers, parents, and all those who care about the development of young people should understand and address life after high school. The report finds that students and all Americans need better and more informed choices for the next step after high school, and at every stage of their careers, as they seek the knowledge and skills that will help them succeed in the workplace and meet their economic necessities. It calls upon parents, students, policymakers, and educators to recognize the realities and opportunities of the changing new economy for people of different educational backgrounds -- and to support the increasing importance of lifelong learning to the success of so many Americans

    The 70 Percent Solution: Five Principles for Helping Young People Make Decisions During and After High School

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    This report offers a different vision of how educators, employers, parents, and all those who care about the development of young people should understand and address life after high school. The report finds that students and all Americans need better and more informed choices for the next step after high school, and at every stage of their careers, as they seek the knowledge and skills that will help them succeed in the workplace and meet their economic necessities. It calls upon parents, students, policymakers, and educators to recognize the realities and opportunities of the changing new economy for people of different educational backgrounds -- and to support the increasing importance of lifelong learning to the success of so many Americans

    Polarization Self-rotation in Ultracold Atomic Rb

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    We report on a combined experimental and theoretical study of polarization self-rotation in an ultracold atomic sample. In the experiments, a probe laser is tuned in the spectral vicinity of the D1 line to observe polarization self-rotation in a sample of ultracold Rb prepared in a magneto-optical trap. Systematic measurements of the rotation angle of the light-polarization ellipse as a function of laser intensity, initial ellipticity and detuning are made. The observations, in good agreement with theoretical simulations, are indicative of the presence of a residual static magnetic field, resulting in measured asymmetries in the rotation angle for right and left ellipticities. In this paper we present our detailed experimental results and analysis of the combined influences of polarization self-rotation and the Faraday effect.Comment: 9 pages, 12 figures Some figures redone for clarity, better explanation for discrepancy of model and experimental dat

    Huddle test measurement of a near Johnson noise limited geophone

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    In this paper, the sensor noise of two geophone configurations (L-22D and L-4C geophones from Sercel with custom built amplifiers) was measured by performing two huddle tests. It is shown that the accuracy of the results can be significantly improved by performing the huddle test in a seismically quiet environment and by using a large number of reference sensors to remove the seismic foreground signal from the data. Using these two techniques, the measured sensor noise of the two geophone configurations matched the calculated predictions remarkably well in the bandwidth of interest (0.01 Hz–100 Hz). Low noise operational amplifiers OPA188 were utilized to amplify the L-4C geophone to give a sensor that was characterized to be near Johnson noise limited in the bandwidth of interest with a noise value of 10−11 m/Hz⎯⎯⎯⎯⎯√10−11 m/Hz at 1 Hz

    Expression profiling of SCN8A and NDUFC2 genes in colorectal carcinoma

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    The expression differences of SCN8A (which encodes type VIII alpha subunit of voltage gated sodium channel) and NDUFC2 (which encodes C2 subunit of Complex I enzyme in oxidative phosphorylation) genes were evaluated in paired colorectal cancer (CRC) tissues which was relied on our partial transcriptome analysis data in cancer cell lines. Materials and Methods: A total of 62 paired tissues of CRC patients (34 male, 28 female) were included in the study. The mRNA levels of SCN8A and NDUFC2 genes were determined by using real-time PCR (qRT-PCR and semiquantitative PCR). Results: SCN8A gene expression level was significantly lower in tumor tissues (p = 0.0128) and in the patients with the age below 45 years (p = 0.0049). There were also meaningful relationships between the gender, grade of CRC, tumor location, histopathological classification, and SCN8A expression. There was no NDUFC2 differential expression. However, the tumors taken from right colon had significantly lower NDUFC2 expression. Conclusion: Although the voltage gated sodium channels (VGSCs) and Complex I (CI) were associated to a number of diseases including different types of cancers, the different subunits of CI and individual members of VGSCs seem to be cancer type-specific in varying proportions. Key Words: colorectal carcinoma, SCN8A, NDUFC2, Complex I, voltage gated sodium channels, gene expression

    Dynamic and volumetric variables reliably predict fluid responsiveness in a porcine model with pleural effusion

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    Background: The ability of stroke volume variation (SVV), pulse pressure variation (PPV) and global end-diastolic volume (GEDV) for prediction of fluid responsiveness in presence of pleural effusion is unknown. The aim of the present study was to challenge the ability of SVV, PPV and GEDV to predict fluid responsiveness in a porcine model with pleural effusions. Methods: Pigs were studied at baseline and after fluid loading with 8 ml kg−1 6% hydroxyethyl starch. After withdrawal of 8 ml kg−1 blood and induction of pleural effusion up to 50 ml kg−1 on either side, measurements at baseline and after fluid loading were repeated. Cardiac output, stroke volume, central venous pressure (CVP) and pulmonary occlusion pressure (PAOP) were obtained by pulmonary thermodilution, whereas GEDV was determined by transpulmonary thermodilution. SVV and PPV were monitored continuously by pulse contour analysis. Results: Pleural effusion was associated with significant changes in lung compliance, peak airway pressure and stroke volume in both responders and non-responders. At baseline, SVV, PPV and GEDV reliably predicted fluid responsiveness (area under the curve 0.85 (p<0.001), 0.88 (p<0.001), 0.77 (p = 0.007). After induction of pleural effusion the ability of SVV, PPV and GEDV to predict fluid responsiveness was well preserved and also PAOP was predictive. Threshold values for SVV and PPV increased in presence of pleural effusion. Conclusions: In this porcine model, bilateral pleural effusion did not affect the ability of SVV, PPV and GEDV to predict fluid responsiveness

    RNA secondary structure prediction from multi-aligned sequences

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    It has been well accepted that the RNA secondary structures of most functional non-coding RNAs (ncRNAs) are closely related to their functions and are conserved during evolution. Hence, prediction of conserved secondary structures from evolutionarily related sequences is one important task in RNA bioinformatics; the methods are useful not only to further functional analyses of ncRNAs but also to improve the accuracy of secondary structure predictions and to find novel functional RNAs from the genome. In this review, I focus on common secondary structure prediction from a given aligned RNA sequence, in which one secondary structure whose length is equal to that of the input alignment is predicted. I systematically review and classify existing tools and algorithms for the problem, by utilizing the information employed in the tools and by adopting a unified viewpoint based on maximum expected gain (MEG) estimators. I believe that this classification will allow a deeper understanding of each tool and provide users with useful information for selecting tools for common secondary structure predictions.Comment: A preprint of an invited review manuscript that will be published in a chapter of the book `Methods in Molecular Biology'. Note that this version of the manuscript may differ from the published versio

    Biogeographic patterns of daily wildfire spread and extremes across North America

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    IntroductionClimate change is predicted to increase the frequency of extreme single-day fire spread events, with major ecological and social implications. In contrast with well-documented spatio-temporal patterns of wildfire ignitions and perimeters, daily progression remains poorly understood across continental spatial scales, particularly for extreme single-day events (“blow ups”). Here, we characterize daily wildfire spread across North America, including occurrence of extreme single-day events, duration and seasonality of fire and extremes, and ecoregional climatic niches of fire in terms of Actual Evapotranspiration (AET) and Climatic Water Deficit (CWD) annual climate normals.MethodsRemotely sensed daily progression of 9,636 wildfires ≥400 ha was used to characterize ecoregional patterns of fire growth, extreme single-day events, duration, and seasonality. To explore occurrence, extent, and impacts of single-day extremes among ecoregions, we considered complementary ecoregional and continental extreme thresholds (Ecoregional or Continental Mean Daily Area Burned + 2SD). Ecoregional spread rates were regressed against AET and CWD to explore climatic influence on spread.ResultsWe found three-fold differences in mean Daily Area Burned among 10 North American ecoregions, ranging from 260 ha day−1 in the Marine West Coast Forests to 751 ha day−1 in Mediterranean California. Ecoregional extreme thresholds ranged from 3,829 ha day−1 to 16,626 ha day−1, relative to a continental threshold of 7,173 ha day−1. The ~3% of events classified as extreme cumulatively account for 16–55% of total area burned among ecoregions. We observed four-fold differences in mean fire duration, ranging from 2.7 days in the Great Plains to 10.5 days in Northwestern Forested Mountains. Regions with shorter fire durations also had greater daily area burned, suggesting a paradigm of fast-growing short-duration fires in some regions and slow-growing long-duration fires elsewhere. CWD had a weak positive relationship with spread rate and extreme thresholds, and there was no pattern for AET.DiscussionRegions with shorter fire durations had greater daily area burned, suggesting a paradigm of fast-growing short-duration fires in some regions and slow-growing long-duration fires elsewhere. Although climatic conditions can set the stage for ignition and influence vegetation and fuels, finer-scale mechanisms likely drive variation in daily spread. Daily fire progression offers valuable insights into the regional and seasonal distributions of extreme single-day spread events, and how these events shape net fire effects

    The LBNO long-baseline oscillation sensitivities with two conventional neutrino beams at different baselines

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    The proposed Long Baseline Neutrino Observatory (LBNO) initially consists of 20\sim 20 kton liquid double phase TPC complemented by a magnetised iron calorimeter, to be installed at the Pyh\"asalmi mine, at a distance of 2300 km from CERN. The conventional neutrino beam is produced by 400 GeV protons accelerated at the SPS accelerator delivering 700 kW of power. The long baseline provides a unique opportunity to study neutrino flavour oscillations over their 1st and 2nd oscillation maxima exploring the L/EL/E behaviour, and distinguishing effects arising from δCP\delta_{CP} and matter. In this paper we show how this comprehensive physics case can be further enhanced and complemented if a neutrino beam produced at the Protvino IHEP accelerator complex, at a distance of 1160 km, and with modest power of 450 kW is aimed towards the same far detectors. We show that the coupling of two independent sub-MW conventional neutrino and antineutrino beams at different baselines from CERN and Protvino will allow to measure CP violation in the leptonic sector at a confidence level of at least 3σ3\sigma for 50\% of the true values of δCP\delta_{CP} with a 20 kton detector. With a far detector of 70 kton, the combination allows a 3σ3\sigma sensitivity for 75\% of the true values of δCP\delta_{CP} after 10 years of running. Running two independent neutrino beams, each at a power below 1 MW, is more within today's state of the art than the long-term operation of a new single high-energy multi-MW facility, which has several technical challenges and will likely require a learning curve.Comment: 21 pages, 12 figure
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