678 research outputs found

    Development of Novel Methods for Characterization of Complex Organic Mixtures By Liquid Chromatography and Raman Spectroscopy

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    ABSTRACT DEVELOPMENT OF NOVEL METHODS FOR CHARACTERIZATION OF COMPLEX ORGANIC MIXTURES BY LIQUID CHROMATOGRAPHY AND RAMAN SPECTROSCOPY by Veronica Marco Alvarez The University of Wisconsin-Milwaukee, 2014 Under the Supervision of Professor Joseph H. Aldstadt III The development of methods for the study of Humic Acids (HAs) and related substances is described. In the first part, a reversed-phase liquid chromatography (RP-LC) instrument was designed, fabricated, and a method for the separation of HAs was optimized for application as the second dimension in a two-dimensional LC (LCxLC) system. The optimized method for the RP-LC was used in the study of amino acid mixtures and HA standard solutions. The RP-LC used a monolithic disk in which the stationary phase was composed of butyl (C4) functional groups. The method had the following conditions: 100 µL injection volume, 1.0 mL/min flow rate, 30:70 acetonitrile:water (pH = 7.00) mobile phase, and fluorescence detection (λex = 257 nm, λex = 310 nm). Several HA fractions from solid-phase extraction separations were examined as a means to simplify the HA standard and their spectra were compared to the characteristic peaks found for HAs in the literature. The next step in this work is to integrate the RP-LC method into the LCxLC system. In the second part of this thesis, the characterization of two natural varnishes -- Linseed Oil and Chinawood Oil-- was studied by accelerated ageing experiments and Fourier Transform Raman Spectroscopy (FT Raman). An ageing chamber designed in our group for a previous investigation was modified to perform the ageing experiments. Two factors were studied over a range of time periods: heat and ultraviolet light. Thermal studies were conducted from 25ᵒC to 210ᵒC while the time periods ranged from 2 to 170 hr. A direct correlation was found between the changes in the vibrational bands that were observed in the FT Raman spectra and the observation of overt physical changes in the samples. Based upon these data, several reaction mechanisms for the decomposition of the varnishes were proposed. The FT Raman method may also be applied in the future to fractions collected from the LCxLC system for a more detailed off-line characterization of the molecular structures that are present

    Risk of progression in chronic phase-chronic myeloid leukemia patients eligible for tyrosine kinase inhibitor discontinuation: Final analysis of the TFR-PRO study

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    Disease progression to accelerated/blast phase (AP/BP) in patients with chronic phase chronic myeloid leukemia (CP-CML) after treatment discontinuation (TD) has never been systematically reported in clinical trials. However, recent reports of several such cases has raised concern. To estimate the risk of AP/BP among TD-eligible patients, we conducted TFR-PRO, a cohort retro-prospective study: 870 CP-CML patients eligible for TD formed a discontinuation cohort (505 patients) and a reference one (365 patients). The primary objective was the time adjusted rate (TAR) of progression in relation to TD. Secondary endpoints included the TAR of molecular relapse, that is, loss of major molecular response (MMR). With a median follow up of 5.5 years and 5188.2 person-years available, no events occurred in the TD cohort. One event of progression was registered 55 months after the end of TD, when the patient was contributing to the reference cohort. The TAR of progression was 0.019/100 person-years (95% CI [0.003-0.138]) in the overall group; 0.0 (95% CI [0-0.163]) in the discontinuation cohort; and 0.030 (95% CI [0.004-0.215]) in the reference cohort. These differences are not statistically significant. Molecular relapses occurred in 172/505 (34.1%) patients after TD, and in 64/365 (17.5%) patients in the reference cohort, p < .0001. Similar rates were observed in TD patients in first, second or third line of treatment. CML progression in patients eligible for TD is rare and not related to TD. Fears about the risk of disease progression among patients attempting TD should be dissipated

    City of Hitchcock Comprehensive Plan 2020-2040

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    Hitchcock is a small town located in Galveston County (Figure 1.1), nestled up on the Texas Gulf Coast. It lies about 40 miles south-east of Houston. The boundaries of the city encloses an area of land of 60.46 sq. miles, an area of water of 31.64 sq. miles at an elevation just 16 feet above sea level. Hitchcock has more undeveloped land (~90% of total area) than the county combined. Its strategic location gives it a driving force of opportunities in the Houston-Galveston Region.The guiding principles for this planning process were Hitchcock’s vision statement and its corresponding goals, which were crafted by the task force. The goals focus on factors of growth and development including public participation, development considerations, transportation, community facilities, economic development, parks, and housing and social vulnerabilityTexas Target Communitie

    Calidad de las elecciones a titular del Ejecutivo en el Centro y Centro-occidente de México

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    Este libro, que tiene por objetivo analizar la calidad de las elecciones celebradas entre 2006 y 2011 para ocupar la titularidad del Poder Ejecutivo de las 14 entidades federativas de la República Mexicana que conforman las regiones Centro y Centro-occidente de este país, ha sido elaborado por investigadores pertenecientes a la Red Nacional de Investigación sobre la Calidad de la Democracia en México (Renicadem), la cual cuenta con un equipo de investigación en cada una de las entidades federativas del país. A su vez, esta Red constituye una de las cuatro líneas temáticas que componen la red temática del Conacyt “Sociedad civil y calidad de la democracia”. Con todo, la presente obra puede considerarse, en dos sentidos, como el resultado parcial de estudios realizados por investigadores que conforman la mencionada Renicadem. Por un lado, trata sólo de una de las varias dimensiones que esta Red ha establecido como necesarias para analizar la calidad de la democracia: la calidad electoral (otras dimensiones, que se encuentran en proceso de investigación, son calidad de vida, rendición de cuentas y Estado de derecho). También es parcial porque no abarca la totalidad de la República Mexicana, sino únicamente a las 14 entidades indicadas.UAE

    Copernicus Ocean State Report, issue 6

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    The 6th issue of the Copernicus OSR incorporates a large range of topics for the blue, white and green ocean for all European regional seas, and the global ocean over 1993–2020 with a special focus on 2020

    Height and body-mass index trajectories of school-aged children and adolescents from 1985 to 2019 in 200 countries and territories: a pooled analysis of 2181 population-based studies with 65 million participants

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    Summary Background Comparable global data on health and nutrition of school-aged children and adolescents are scarce. We aimed to estimate age trajectories and time trends in mean height and mean body-mass index (BMI), which measures weight gain beyond what is expected from height gain, for school-aged children and adolescents. Methods For this pooled analysis, we used a database of cardiometabolic risk factors collated by the Non-Communicable Disease Risk Factor Collaboration. We applied a Bayesian hierarchical model to estimate trends from 1985 to 2019 in mean height and mean BMI in 1-year age groups for ages 5–19 years. The model allowed for non-linear changes over time in mean height and mean BMI and for non-linear changes with age of children and adolescents, including periods of rapid growth during adolescence. Findings We pooled data from 2181 population-based studies, with measurements of height and weight in 65 million participants in 200 countries and territories. In 2019, we estimated a difference of 20 cm or higher in mean height of 19-year-old adolescents between countries with the tallest populations (the Netherlands, Montenegro, Estonia, and Bosnia and Herzegovina for boys; and the Netherlands, Montenegro, Denmark, and Iceland for girls) and those with the shortest populations (Timor-Leste, Laos, Solomon Islands, and Papua New Guinea for boys; and Guatemala, Bangladesh, Nepal, and Timor-Leste for girls). In the same year, the difference between the highest mean BMI (in Pacific island countries, Kuwait, Bahrain, The Bahamas, Chile, the USA, and New Zealand for both boys and girls and in South Africa for girls) and lowest mean BMI (in India, Bangladesh, Timor-Leste, Ethiopia, and Chad for boys and girls; and in Japan and Romania for girls) was approximately 9–10 kg/m2. In some countries, children aged 5 years started with healthier height or BMI than the global median and, in some cases, as healthy as the best performing countries, but they became progressively less healthy compared with their comparators as they grew older by not growing as tall (eg, boys in Austria and Barbados, and girls in Belgium and Puerto Rico) or gaining too much weight for their height (eg, girls and boys in Kuwait, Bahrain, Fiji, Jamaica, and Mexico; and girls in South Africa and New Zealand). In other countries, growing children overtook the height of their comparators (eg, Latvia, Czech Republic, Morocco, and Iran) or curbed their weight gain (eg, Italy, France, and Croatia) in late childhood and adolescence. When changes in both height and BMI were considered, girls in South Korea, Vietnam, Saudi Arabia, Turkey, and some central Asian countries (eg, Armenia and Azerbaijan), and boys in central and western Europe (eg, Portugal, Denmark, Poland, and Montenegro) had the healthiest changes in anthropometric status over the past 3·5 decades because, compared with children and adolescents in other countries, they had a much larger gain in height than they did in BMI. The unhealthiest changes—gaining too little height, too much weight for their height compared with children in other countries, or both—occurred in many countries in sub-Saharan Africa, New Zealand, and the USA for boys and girls; in Malaysia and some Pacific island nations for boys; and in Mexico for girls. Interpretation The height and BMI trajectories over age and time of school-aged children and adolescents are highly variable across countries, which indicates heterogeneous nutritional quality and lifelong health advantages and risks

    Study of the BΛc+ΛˉcKB^{-} \to \Lambda_{c}^{+} \bar{\Lambda}_{c}^{-} K^{-} decay

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    The decay BΛc+ΛˉcKB^{-} \to \Lambda_{c}^{+} \bar{\Lambda}_{c}^{-} K^{-} is studied in proton-proton collisions at a center-of-mass energy of s=13\sqrt{s}=13 TeV using data corresponding to an integrated luminosity of 5 fb1\mathrm{fb}^{-1} collected by the LHCb experiment. In the Λc+K\Lambda_{c}^+ K^{-} system, the Ξc(2930)0\Xi_{c}(2930)^{0} state observed at the BaBar and Belle experiments is resolved into two narrower states, Ξc(2923)0\Xi_{c}(2923)^{0} and Ξc(2939)0\Xi_{c}(2939)^{0}, whose masses and widths are measured to be m(Ξc(2923)0)=2924.5±0.4±1.1MeV,m(Ξc(2939)0)=2938.5±0.9±2.3MeV,Γ(Ξc(2923)0)=0004.8±0.9±1.5MeV,Γ(Ξc(2939)0)=0011.0±1.9±7.5MeV, m(\Xi_{c}(2923)^{0}) = 2924.5 \pm 0.4 \pm 1.1 \,\mathrm{MeV}, \\ m(\Xi_{c}(2939)^{0}) = 2938.5 \pm 0.9 \pm 2.3 \,\mathrm{MeV}, \\ \Gamma(\Xi_{c}(2923)^{0}) = \phantom{000}4.8 \pm 0.9 \pm 1.5 \,\mathrm{MeV},\\ \Gamma(\Xi_{c}(2939)^{0}) = \phantom{00}11.0 \pm 1.9 \pm 7.5 \,\mathrm{MeV}, where the first uncertainties are statistical and the second systematic. The results are consistent with a previous LHCb measurement using a prompt Λc+K\Lambda_{c}^{+} K^{-} sample. Evidence of a new Ξc(2880)0\Xi_{c}(2880)^{0} state is found with a local significance of 3.8σ3.8\,\sigma, whose mass and width are measured to be 2881.8±3.1±8.5MeV2881.8 \pm 3.1 \pm 8.5\,\mathrm{MeV} and 12.4±5.3±5.8MeV12.4 \pm 5.3 \pm 5.8 \,\mathrm{MeV}, respectively. In addition, evidence of a new decay mode Ξc(2790)0Λc+K\Xi_{c}(2790)^{0} \to \Lambda_{c}^{+} K^{-} is found with a significance of 3.7σ3.7\,\sigma. The relative branching fraction of BΛc+ΛˉcKB^{-} \to \Lambda_{c}^{+} \bar{\Lambda}_{c}^{-} K^{-} with respect to the BD+DKB^{-} \to D^{+} D^{-} K^{-} decay is measured to be 2.36±0.11±0.22±0.252.36 \pm 0.11 \pm 0.22 \pm 0.25, where the first uncertainty is statistical, the second systematic and the third originates from the branching fractions of charm hadron decays.Comment: All figures and tables, along with any supplementary material and additional information, are available at https://cern.ch/lhcbproject/Publications/p/LHCb-PAPER-2022-028.html (LHCb public pages

    Measurement of the ratios of branching fractions R(D)\mathcal{R}(D^{*}) and R(D0)\mathcal{R}(D^{0})

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    The ratios of branching fractions R(D)B(BˉDτνˉτ)/B(BˉDμνˉμ)\mathcal{R}(D^{*})\equiv\mathcal{B}(\bar{B}\to D^{*}\tau^{-}\bar{\nu}_{\tau})/\mathcal{B}(\bar{B}\to D^{*}\mu^{-}\bar{\nu}_{\mu}) and R(D0)B(BD0τνˉτ)/B(BD0μνˉμ)\mathcal{R}(D^{0})\equiv\mathcal{B}(B^{-}\to D^{0}\tau^{-}\bar{\nu}_{\tau})/\mathcal{B}(B^{-}\to D^{0}\mu^{-}\bar{\nu}_{\mu}) are measured, assuming isospin symmetry, using a sample of proton-proton collision data corresponding to 3.0 fb1{ }^{-1} of integrated luminosity recorded by the LHCb experiment during 2011 and 2012. The tau lepton is identified in the decay mode τμντνˉμ\tau^{-}\to\mu^{-}\nu_{\tau}\bar{\nu}_{\mu}. The measured values are R(D)=0.281±0.018±0.024\mathcal{R}(D^{*})=0.281\pm0.018\pm0.024 and R(D0)=0.441±0.060±0.066\mathcal{R}(D^{0})=0.441\pm0.060\pm0.066, where the first uncertainty is statistical and the second is systematic. The correlation between these measurements is ρ=0.43\rho=-0.43. Results are consistent with the current average of these quantities and are at a combined 1.9 standard deviations from the predictions based on lepton flavor universality in the Standard Model.Comment: All figures and tables, along with any supplementary material and additional information, are available at https://cern.ch/lhcbproject/Publications/p/LHCb-PAPER-2022-039.html (LHCb public pages

    Multidifferential study of identified charged hadron distributions in ZZ-tagged jets in proton-proton collisions at s=\sqrt{s}=13 TeV

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    Jet fragmentation functions are measured for the first time in proton-proton collisions for charged pions, kaons, and protons within jets recoiling against a ZZ boson. The charged-hadron distributions are studied longitudinally and transversely to the jet direction for jets with transverse momentum 20 <pT<100< p_{\textrm{T}} < 100 GeV and in the pseudorapidity range 2.5<η<42.5 < \eta < 4. The data sample was collected with the LHCb experiment at a center-of-mass energy of 13 TeV, corresponding to an integrated luminosity of 1.64 fb1^{-1}. Triple differential distributions as a function of the hadron longitudinal momentum fraction, hadron transverse momentum, and jet transverse momentum are also measured for the first time. This helps constrain transverse-momentum-dependent fragmentation functions. Differences in the shapes and magnitudes of the measured distributions for the different hadron species provide insights into the hadronization process for jets predominantly initiated by light quarks.Comment: All figures and tables, along with machine-readable versions and any supplementary material and additional information, are available at https://cern.ch/lhcbproject/Publications/p/LHCb-PAPER-2022-013.html (LHCb public pages

    Search for dark matter produced in association with bottom or top quarks in √s = 13 TeV pp collisions with the ATLAS detector

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    A search for weakly interacting massive particle dark matter produced in association with bottom or top quarks is presented. Final states containing third-generation quarks and miss- ing transverse momentum are considered. The analysis uses 36.1 fb−1 of proton–proton collision data recorded by the ATLAS experiment at √s = 13 TeV in 2015 and 2016. No significant excess of events above the estimated backgrounds is observed. The results are in- terpreted in the framework of simplified models of spin-0 dark-matter mediators. For colour- neutral spin-0 mediators produced in association with top quarks and decaying into a pair of dark-matter particles, mediator masses below 50 GeV are excluded assuming a dark-matter candidate mass of 1 GeV and unitary couplings. For scalar and pseudoscalar mediators produced in association with bottom quarks, the search sets limits on the production cross- section of 300 times the predicted rate for mediators with masses between 10 and 50 GeV and assuming a dark-matter mass of 1 GeV and unitary coupling. Constraints on colour- charged scalar simplified models are also presented. Assuming a dark-matter particle mass of 35 GeV, mediator particles with mass below 1.1 TeV are excluded for couplings yielding a dark-matter relic density consistent with measurements
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