Offset frequency dynamics and phase noise properties of a self-referenced 10 GHz Ti:sapphire frequency comb

This paper shows the experimental details of the stabilization scheme that allows full control of the repetition rate and the carrier-envelope offset frequency of a 10 GHz frequency comb based on a femtosecond Ti:sapphire laser. Octave-spanning spectra are produced in nonlinear microstructured optical fiber, in spite of the reduced peak power associated with the 10 GHz repetition rate. Improved stability of the broadened spectrum is obtained by temperature-stabilization of the nonlinear optical fiber. The carrier-envelope offset frequency and the repetition rate are simultaneously frequency stabilized, and their short- and long-term stabilities are characterized. We also measure the transfer of amplitude noise of the pump source to phase noise on the offset frequency and verify an increased sensitivity of the offset frequency to pump power modulation compared to systems with lower repetition rate. Finally, we discuss merits of this 10 GHz system for the generation of low-phase-noise microwaves

Bayesian splines versus fractional polynomials in network meta-analysis

BACKGROUND: Network meta-analysis (NMA) provides a powerful tool for the simultaneous evaluation of multiple treatments by combining evidence from different studies, allowing for direct and indirect comparisons between treatments. In recent years, NMA is becoming increasingly popular in the medical literature and underlying statistical methodologies are evolving both in the frequentist and Bayesian framework. Traditional NMA models are often based on the comparison of two treatment arms per study. These individual studies may measure outcomes at multiple time points that are not necessarily homogeneous across studies. METHODS: In this article we present a Bayesian model based on B-splines for the simultaneous analysis of outcomes across time points, that allows for indirect comparison of treatments across different longitudinal studies. RESULTS: We illustrate the proposed approach in simulations as well as on real data examples available in the literature and compare it with a model based on P-splines and one based on fractional polynomials, showing that our approach is flexible and overcomes the limitations of the latter. CONCLUSIONS: The proposed approach is computationally efficient and able to accommodate a large class of temporal treatment effect patterns, allowing for direct and indirect comparisons of widely varying shapes of longitudinal profiles

The Rotationally-Resolved Absorption Spectrum of Formaldehyde from 6547 to 7051 cm−1

We report new experimental data on the rotationally resolved room temperature absorption spectrum of CH2O in the near infrared (NIR) region between 6804 and 7051 cm–1 (1470–1418 nm). Data have been obtained by cavity enhanced absorption spectroscopy and complement the spectrum in the wavelength range 6547–6804 cm–1, obtained using virtually the same experimental set-up and already published in an earlier publication (Staak et al., J. Mol. Spectrosc. 229 (2005) 115–121). Several vibrational combination bands occur in this region and give rise to a congested spectrum and over 4500 lines with cross- sections over 5 · 10–23 cm2 were observed. Recent experimental studies using NIR absorption spectroscopy for quantifying CH2O in different chemical systems indicate that the absorption cross-sections obtained by Staak et al. may have been overestimated. The results of these experiments are reviewed here and a recommendation for absolute absorption cross sections of CH2O in the NIR range will be given. Absolute absorption cross-sections stated here are corrected by the recommended factor

Myelin abnormalities in the optic and sciatic nerves of mice with GM1-gangliosidosis

Thesis advisor: Thomas N. SeyfriedGM1 gangliosidosis is a glycosphingolipid lysosomal storage disease caused by a genetic deficiency of acid b-galactosidase (β-gal), the enzyme that catabolyzes GM1 within lysosomes. Accumulation of GM1 and its asialo form (GA1) occurs primarily in the brain, leading to progressive neurodegeneration and brain dysfunction. Less information is available on the neurochemical pathology in optic nerve and sciatic nerve of GM1- gangliosidosis. Here we analyzed the lipid content and myelin structure in optic and sciatic nerve in 7 and 10 month old normal β-gal (+/?) and GM1-gangliosidosis β-gal (-/-) mice. Optic nerve weight was lower in the β-gal -/- mice than in unaffected β-gal +/? mice, but no difference was seen between the normal and the β-gal -/- mice for sciatic nerve weight. The concentrations of GM1 and GA1 were significantly higher in optic nerve and sciatic nerve in the β-gal -/- mice than in β-gal +/? mice. The content and composition of myelin-enriched cerebrosides, sulfatides, plasmalogen ethanolamines were significantly lower in optic nerve of β-gal -/- mice than in β-gal +/? mice, however cholesteryl esters were enriched in the β-gal -/- mice. No significant abnormalities in these myelin enriched lipids were detected in sciatic nerve of the β-gal -/- mice. The abnormalities in GM1 and myelin lipids in optic nerve of β-gal -/- mice were also associated with abnormalities in the X-ray diffraction pattern including myelin content in fresh nerves [M/(M +B)] and periodicity (d). With the exception of a slight reduction in myelin content, no abnormalities in the X-ray diffraction pattern were observed in sciatic nerve of β-gal -/- mice. The results indicate that neurochemical pathology is greater in optic nerve than in sciatic nerve of β-gal -/- mice.Thesis (MS) — Boston College, 2014.Submitted to: Boston College. Graduate School of Arts and Sciences.Discipline: Biology

Bayesian Deconvolution and Quantification of Metabolites from J-Resolved NMR Spectroscopy

Two-dimensional (2D) nuclear magnetic resonance (nmr) methods have become increasingly popular in metabolomics, since they have considerable potential to accurately identify and quantify metabolites within complex biological samples. 2D 1 H J-resolved (jres) nmr spectroscopy is a widely used method that expands overlapping resonances into a second dimension. However, existing analytical processing methods do not fully exploit the information in the jres spectrum and, more importantly, do not provide measures of uncertainty associated with the estimates of quantities of interest, such as metabolite concentration. Combining the data-generating mechanisms and the extensive prior knowledge available in online databases, we develop a Bayesian method to analyse 2D jres data, which allows for automatic deconvolution, identification and quantification of metabolites. The model extends and improves previous work on one-dimensional nmr spectral data. Our approach is based on a combination of B-spline tight wavelet frames and theoretical templates, and thus enables the automatic incorporation of expert knowledge within the inferential framework. Posterior inference is performed through specially devised Markov chain Monte Carlo methods. We demonstrate the performance of our approach via analyses of datasets from serum and urine, showing the advantages of our proposed approach in terms of identification and quantification of metabolites

Gender agreement on adverbs in Spanish

In this article we explore the exceptional gender agreement of the Spanish adverb mucho (‘much’), when it modifies comparative adjectives inside DPs that contain a particular type of noun (as in muchafem mejor intenciónfem, ‘much better intention’). This phenomenon, which we describe in detail, raises crucial questions both about the mechanisms of agreement and about the nature of gender in a language such as Spanish. We will argue on the basis of our analysis that agreement is not semantically motivated, but blindly triggered by certain formal configurations. We will also argue that –at least in languages such as Spanish– gender information is scattered in two different positions inside the DP.Peer reviewe

Организационные резервы повышения производительности труда на предприятиях нефтегазовой отрасли

Проблема повышения производительности труда в современной экономике России имеет значительную актуальность, поскольку повышение уровня производительности труда является важнейшим условием социально-экономического развития общества, устойчивого экономического роста и повышения конкурентоспособности национальной экономики. Актуальность представленного исследования определяется необходимостью повышения производительности труда на современных предприятиях России, что может быть достигнуто за счет реализации организационных резервов роста. Целью исследования является структурирование факторов, оказывающих влияние на уровень производительности труда, подтверждение значимости организационных резервов роста, апробация методики выявления организационных резервов повышения производительности труда. Методы исследования. В настоящей работе нашли применение методы сбора первичной экономической информации, включая анализ законодательных и нормативно-правовых актов РФ, официальных статистических данных, данных публичной отчетности отечественных предприятий, анализ прочих открытых источников информации, системный подход, методы статистического и сравнительного анализа. The country's labor productivity in modern Russia over recent years has acquired impressive relevance. Since it is a key indicator of overall economic efficiency, strong labor productivity growth has always been a sufficient condition for socio-economic development, economic stability and enhancing competitiveness of the national economy. The relevance of the study is determined by the urgency of the labor productivity growth at the modern Russian factories that can be achieved through realization of organizational reserves. The main aim of the study is identifying and structuring the factors that seem to affect labor productivity level. It is also pointed at corroborating the necessity of labor productivity growth and approbation of organizational reserves seeking method. Methods. In the present work different methods of information gathering and processing were used to obtain the economic data including the analysis of appropriate laws and regulations, official statistics, companies' public statements and reporting and other open available resources. Also system approach, comparative and statistical analysis were adopted in this research

Hc2 of anisotropy two-band superconductors by Ginzburg-Landau approach

The purpose of this research is to study the upper critical field (Hc2) of two-band superconductors by two-band Ginzburg - Landau approach. The analytical formula of Hc2 included anisotropy of order parameter and anisotropy of effective-mass are found . The parameters of the upper critical field in ab-plane and c-axis can be found by fitting to the experimental data . Finally, we can find the ratio of upper critical field that temperature dependent in the range of experimental result .Comment: 10 pages. accepted by Physica