3,314 research outputs found

    Solar Neutrino Results from the Sudbury Neutrino Observatory

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    We describe here the measurement of the flux of neutrinos created by the decay of solar ^8B by the Sudbury Neutrino Observatory (SNO). The neutrinos were detected via the charged current (CC) reaction on deuterium and by the elastic scattering (ES) of electrons. The CC reaction is sensitive exclusively to νe\nu_e's, while the ES reaction also has a small sensitivity to νμ\nu_{\mu}'s and ντ\nu_{\tau}'s. The flux of νe\nu_e's from ^8B decay measured by the CC reaction rate is ϕCC(νe)=1.75±0.07(stat.)0.11+0.12(sys.)±0.05(theor.)×106cm2s1\phi^CC (\nu_e) = 1.75 \pm 0.07 (stat.)^{+0.1 2}_{-0.11} (sys.) \pm 0.05 (theor.) \times 10^6 cm^-2 s^-1. Assuming no flavor transformation, the flux inferred from the ES reaction rate is ϕES(νx)=2.39±0.34(stat.)0.14+0.16(sys.)×106cm2s1\phi^ES (\nu_x)=2.39\pm 0.34 (stat.) ^{+0.16}_{-0.14} (sys.) \times 10^6 cm^-2 s^-1. Comparison of ϕCC(νe)\phi^CC (\nu_e) to the Super-Kamiokande Collaboration's precision value of ϕES(νx)\phi^ES (\nu_x) yields a 3.3σ3.3\sigma difference, assuming the systematic uncertainties are normally distributed, providing evidence that there is a non-electron flavor active neutrino component in the solar flux. The total flux of active ^8B neutrinos is thus determined to be 5.44±0.99×106cm2s15.44\pm 0.99 \times 10^6 cm^-2 s^-1, in close agreement with the predictions of solar models.Comment: Talk given at the XX International Symposium on Lepton and Photon Interactions at High Energie

    Few and Far Between: How HIV May Be Evading Antibody Avidity

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    Prototype Detector for Ultrahigh Energy Neutrino Detection

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    Necessary technical experience is being gained from successful construction and deployment of current prototype detectors to search for UHE neutrinos in Antarctica, Lake Baikal in Russia, and the Mediterranean. The prototype detectors have also the important central purpose of determining whether or not UHE neutrinos do in fact exist in nature by observation of at least a few UHE neutrino-induced leptons with properties that are not consistent with expected backgrounds. We discuss here the criteria for a prototype detector to accomplish that purpose in a convincing way even if the UHE neutrino flux is substantially lower than predicted at present.Comment: 18 pages, 8 figures, submitted to Astroparticle Physic

    Towards precision distances and 3D dust maps using broadband Period--Magnitude relations of RR Lyrae stars

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    We determine the period-magnitude relations of RR Lyrae stars in 13 photometric bandpasses from 0.4 to 12 {\mu}m using timeseries observations of 134 stars. The Bayesian formalism, extended from our previous work to include the effects of line-of-sight dust extinction, allows for the simultaneous inference of the posterior distribution of the mean absolute magnitude, slope of the period-magnitude power-law, and intrinsic scatter about a perfect power-law for each bandpass. In addition, the distance modulus and line-of-sight dust extinction to each RR Lyrae star in the calibration sample is determined, yielding a sample median fractional distance error of 0.66%. The intrinsic scatter in all bands appears to be larger than the photometric errors, except in WISE W1 (3.4 {\mu}m) and W2 (4.6 {\mu}m) where the photometric error (σ0.05\sigma \approx 0.05 mag) is to be comparable or larger than the intrinsic scatter. Additional observations at these wavelengths could improve the inferred distances to these sources further. As an application of the methodology, we infer the distance to the RRc-type star RZCep at low Galactic latitude (b=5.5b = 5.5^\circ) to be μ=8.0397±0.0123\mu=8.0397\pm0.0123 mag (405.4±2.3405.4\pm2.3 pc) with colour excess E(BV)=0.2461±0.0089E(B-V)=0.2461\pm0.0089 mag. This distance, equivalent to a parallax of 2467±142467\pm14 microarcsec, is consistent with the published HST parallax measurement but with an uncertainty that is 13 times smaller than the HST measurement. If our measurements (and methodology) hold up to scrutiny, the distances to these stars have been determined to an accuracy comparable to those expected with Gaia. As RR Lyrae are one of the primary components of the cosmic distance ladder, the achievement of sub-1% distance errors within a formalism that accounts for dust extinction may be considered a strong buttressing of the path to eventual 1% uncertainties in Hubble's constant.Comment: 21 pages, 29 figures, 2 tables, abstract abridged for arXiv. Comments solicited on referee report (received June 9, 2014) linked: https://gist.github.com/profjsb/c6c4e2f3a20ea02f1762 . Public archive of code used to generate results and figures: https://github.com/ckleinastro/period_luminosity_relation_fittin

    Nucleus: A Pilot Project

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    Early in 2016, an environmental scan was conducted by the Research Library Data Working Group for three purposes: 1.) Perform a survey of the data management landscape at Los Alamos National Laboratory in order to identify local gaps in data management services. 2.) Conduct an environmental scan of external institutions to benchmark budgets, infrastructure, and personnel dedicated to data management. 3.) Draft a research data infrastructure model that aligns with the current workflow and classification restrictions at Los Alamos National Laboratory. This report is a summary of those activities and the draft for a pilot data management project.Comment: 13 pages, repor

    Activity-dependent modulation of neuronal sodium channel expression

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    Electoral Recall in Washington State and California: California Needs Stricter Standards to Protect Elected Officials from Harassment

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    This article highlights the weaknesses of the electoral recall mechanisms in California and the way in which the Washington recall process has avoided such weaknesses. Part II provides general background information on the development of recall mechanisms. Part III explores how the United States Supreme Court has ruled on recall attempts and the specific guidance the Court has provided for states in developing adequately protective recall processes. Part IV analyzes the strengths and weaknesses of the California recall provisions by examining the recall-related opinions of California courts and the complexities of Governor Davis\u27s recall. Part V provides a solution to the California dilemma by exploring an alternative form of recall established in Washington, examines both the constitutional and statutory provisions of Washington\u27s recall mechanism, and analyzes Washington courts\u27 interpretation of these provisions. After comparing the two recall regimes, Part V argues that the Washington mechanism is superior to California\u27s process. Finally, Part VI urges California legislators to promote the true purposes of recall by ensuring government accountability and public participation while minimizing the risks of hindering the government functioning that such harassment of elected officials tends to elicit

    Algorithms for integrated analysis of glycomics and glycoproteomics by LC-MS/MS

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    The glycoproteome is an intricate and diverse component of a cell, and it plays a key role in the definition of the interface between that cell and the rest of its world. Methods for studying the glycoproteome have been developed for released glycan glycomics and site-localized bottom-up glycoproteomics using liquid chromatography-coupled mass spectrometry and tandem mass spectrometry (LC-MS/MS), which is itself a complex problem. Algorithms for interpreting these data are necessary to be able to extract biologically meaningful information in a high throughput, automated context. Several existing solutions have been proposed but may be found lacking for larger glycopeptides, for complex samples, different experimental conditions, different instrument vendors, or even because they simply ignore fundamentals of glycobiology. I present a series of open algorithms that approach the problem from an instrument vendor neutral, cross-platform fashion to address these challenges, and integrate key concepts from the underlying biochemical context into the interpretation process. In this work, I created a suite of deisotoping and charge state deconvolution algorithms for processing raw mass spectra at an LC scale from a variety of instrument types. These tools performed better than previously published algorithms by enforcing the underlying chemical model more strictly, while maintaining a higher degree of signal fidelity. From this summarized, vendor-normalized data, I composed a set of algorithms for interpreting glycan profiling experiments that can be used to quantify glycan expression. From this I constructed a graphical method to model the active biosynthetic pathways of the sample glycome and dig deeper into those signals than would be possible from the raw data alone. Lastly, I created a glycopeptide database search engine from these components which is capable of identifying the widest array of glycosylation types available, and demonstrate a learning algorithm which can be used to tune the model to better understand the process of glycopeptide fragmentation under specific experimental conditions to outperform a simpler model by between 10% and 15%. This approach can be further augmented with sample-wide or site-specific glycome models to increase depth-of-coverage for glycoforms consistent with prior beliefs

    Reading Ability and Success in Algebra 1: Using Reading Scores and Regression to Predict Success on the Ohio Algebra 1 EOC

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    The state of Ohio requires high school students to meet course credit and testing requirements in order to graduate. The purpose of standardized testing is to ensure all students are being taught and learning the same standards at the same proficient level. An algebra teacher who is already teaching the Ohio algebra standards would assume that students would be successful on the algebra 1 EOC exam. When students are not successful, it becomes necessary to determine where instruction has failed, or what interventions must be used to supplement learning to achieve success. Because these are high-stakes tests, being able to determine before instruction which students need more attention and supplementing that instruction from the start can be much more beneficial. One goal of this study was to use data that can be easily accessed to determine which students are more likely to need additional support to improve student achievement. The other main purpose was to determine the need to include reading intervention strategies, content specific reading, working on interpreting word problems, and putting a focus on vocabulary within our lessons will help to improve reading strategies and comprehension. Linear regression techniques were used to determine that a Star instructional reading level reliably predicts scores for the algebra 1 EOC exam. Combined with other predictors, multiple regression analysis compiled an equation to predict algebra 1 EOC scores. A statistically reliable model included Star instructional reading level, eighth-grade course grade and math EOC score, and school district to predict the algebra 1 EOC score. Logistic regression methods were used to create a model to predict success on the algebra 1 EOC exam. Success is defined as a score of 684 or higher on the Ohio algebra 1 EOC. The full model was statistically significant with all predictors, but the reduced model was a better fit with the data. The backward step regression reduced the model to four predictors: 8th grade English course grade and EOC, math EOC, and gender. Again, as predicted reading and comprehension skills are predictive of success on the algebra 1 EOC exam. The results confirmed that reading and comprehension skills are necessary, foundational skills needed to be successful in algebra. The researchers determined formulas to be used to help predict scores on the algebra 1 EOC or predict success on the algebra 1 EOC. Using these formulas, students can be identified before starting algebra to better supplement instruction and provide strategies to support struggling readers. Ultimately if students are below a certain reading level additional reading support could be provided in addition to differentiations in the algebra course. The results imply that there is an undeniable literacy component to the algebra 1 EOC exam
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