149 research outputs found

    Compression wood in Pinus radiata II: Density and chemical composition

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    Ten 22 year old radiata pine trees growing in two stands in Chile, one in clay and the other in humid sand soils showing some lean, were assessed for chemical composition and wood density of compres-sion wood.Signifi cant differences in type of wood in density (33 kg/m3), lignin (1.944 %), alpha-cellulose (-2.634 %), ethanol toluene extractives (0.567 %) and pentose (0.742 %) were found between matched sample of compression and opposite woods.Differences in juvenile and mature wood were signifi cant for both density (-4 kg/m3) and pentose (1.628 %), and site differences were found for wood density (28 kg/m3), extractives (0.978 %) and apparent for alpha cellulose (1.223%).In comparison with other studies, our results suggested that the compression wood formed from trees with light visible lean corresponded to a mild compression class.Se analizó la madera de compresión en diez árboles de 22 años de edad de Pinus radiata D Don creciendo en dos sitios en Chile, uno en suelo de arena húmeda y el otro en suelo arcilloso. Singulari-dades de la madera de compresión y madera opuesta se compararon en estos árboles con inclinaciones menores a 10º y excentricidades reducidas.Diferencias signifi cativas se registraron entre madera de compresión y opuesta en los valores regis-trados para la densidad  básica de 33 (kg/m3), en proporción de lignina de 1.944 (%), en alfa-celulosa de -2.634 (%), en pentosanos de 0.742 (%) y en extraíbles en etanol-tolueno de 0.978 (%) y aparentemente diferente en el caso de alfa celulosa en 1.223 (%).Las diferencias entre  madera  juvenil y madera madura fueron signifi cativas en los casos de la densidad de -4 (kg/m3) y en pentosanos en 1.628 (%), y diferencias entre los dos sitios para los casos de la densidad con 28 (kg/m3), en extractivos con 0.978 (%) y diferencias moderadas en alfa celulosa con 1.223 (%).Las diferencias y coincidencias de estos resultados con los de otros autores se han considerado para estimar que la madera de compresión formada por estos árboles, con inclinaciones reducidas, corres-pondería al tipo de madera de compresión leve

    Infrared Observations of AR Ursae Majoris: Modeling the Ellipsoidal Variations

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    We have obtained time-series infrared photometry for the highly magnetic cataclysmic variable AR UMa. Our J and K' band observations occurred during a low state and they show a distinctive double-humped structure. Using detailed models for the expected ellipsoidal variations in the infrared due to the non-spherical secondary star, we find that the most likely value for the system inclination is 70 degrees. We also model low state V band photometry and find that its observed double-humped structure is not caused by ellipsoidal variations, as they have been ascribed to, but are due to beamed cyclotron radiation. We use this result to estimate the magnetic field strength of the active southern accretion region (B <= 190 MG) and its magnetic longitude (330 degrees).Comment: Accepted to AJ, to appear Jan 2001 issu

    Infrared Observations of Nova Muscae 1991: Black Hole Mass Determination from Ellipsoidal Variations

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    We have obtained infrared photometry for the soft x-ray transient GU Mus. We present J and K_s band light curves modeled with WD98, the newest version of the Wilson-Devinney light curve modeling code. Using detailed models for the expected ellipsoidal variations due to the non-spherical secondary star, we show that the most likely value for the orbital inclination is 54 +/-1.5 deg. This inclination angle is consistent with those previously published, but has a much smaller error. This inclination implies a primary black hole mass of 6.95 +/-0.6 M_sun. While we do not see any evidence for contamination of our infrared light curves from other sources in the system, a conservative model with a contamination level of 15% increases the uncertainty in the inclination angle to 54 +4/-1.5 deg.Comment: 20 pages, 4 figures, Accepted to A

    Sub- and above barrier fusion of loosely bound 6^6Li with 28^{28}Si

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    Fusion excitation functions are measured for the system 6^6Li+28^{28}Si using the characteristic γ\gamma-ray method, encompassing both the sub-barrier and above barrier regions, viz., ElabE_{lab}= 7-24 MeV. Two separate experiments were performed, one for the above barrier region (ElabE_{lab}= 11-24 MeV) and another for the below barrier region (ElabE_{lab}= 7-10 MeV). The results were compared with our previously measured fusion cross section for the 7^7Li+28^{28}Si system. We observed enhancement of fusion cross section at sub-barrier regions for both 6^6Li and 7^7Li, but yield was substantially larger for 6^6Li. However, for well above barrier regions, similar type of suppression was identified for both the systems.Comment: 8 pages, 6 figures, as accepted for publication in Eur.Phys.J.

    Expected Performance of the ATLAS Experiment - Detector, Trigger and Physics

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    A detailed study is presented of the expected performance of the ATLAS detector. The reconstruction of tracks, leptons, photons, missing energy and jets is investigated, together with the performance of b-tagging and the trigger. The physics potential for a variety of interesting physics processes, within the Standard Model and beyond, is examined. The study comprises a series of notes based on simulations of the detector and physics processes, with particular emphasis given to the data expected from the first years of operation of the LHC at CERN

    The ATLAS Data Acquisition and High-Level Trigger: Concept, Design and Status

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    The Trigger and Data Acquisition system (TDAQ) of the ATLAS experiment at the CERN Large Hadron Collider is based on a multi-level selection process and a hierarchical acquisition tree. The system, consisting of a combination of custom electronics and commercial products from the computing and telecommunication industry, is required to provide an online selection power of 105 and a total throughput in the range of Terabit/sec. This paper introduces the basic system requirements and concepts, describes the architecture of the system, discusses the basic measurements supporting the validity of the design and reports on the actual status of construction and installation

    Countdown to 2030 : tracking progress towards universal coverage for reproductive, maternal, newborn, and child health

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    Building upon the successes of Countdown to 2015, Countdown to 2030 aims to support the monitoring and measurement of women's, children's, and adolescents' health in the 81 countries that account for 95% of maternal and 90% of all child deaths worldwide. To achieve the Sustainable Development Goals by 2030, the rate of decline in prevalence of maternal and child mortality, stillbirths, and stunting among children younger than 5 years of age needs to accelerate considerably compared with progress since 2000. Such accelerations are only possible with a rapid scale-up of effective interventions to all population groups within countries (particularly in countries with the highest mortality and in those affected by conflict), supported by improvements in underlying socioeconomic conditions, including women's empowerment. Three main conclusions emerge from our analysis of intervention coverage, equity, and drivers of reproductive, maternal, newborn, and child health (RMNCH) in the 81 Countdown countries. First, even though strong progress was made in the coverage of many essential RMNCH interventions during the past decade, many countries are still a long way from universal coverage for most essential interventions. Furthermore, a growing body of evidence suggests that available services in many countries are of poor quality, limiting the potential effect on RMNCH outcomes. Second, within-country inequalities in intervention coverage are reducing in most countries (and are now almost non-existent in a few countries), but the pace is too slow. Third, health-sector (eg, weak country health systems) and non-health-sector drivers (eg, conflict settings) are major impediments to delivering high-quality services to all populations. Although more data for RMNCH interventions are available now, major data gaps still preclude the use of evidence to drive decision making and accountability. Countdown to 2030 is investing in improvements in measurement in several areas, such as quality of care and effective coverage, nutrition programmes, adolescent health, early childhood development, and evidence for conflict settings, and is prioritising its regional networks to enhance local analytic capacity and evidence for RMNCH

    Circulating microRNAs in sera correlate with soluble biomarkers of immune activation but do not predict mortality in ART treated individuals with HIV-1 infection: A case control study

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    Introduction: The use of anti-retroviral therapy (ART) has dramatically reduced HIV-1 associated morbidity and mortality. However, HIV-1 infected individuals have increased rates of morbidity and mortality compared to the non-HIV-1 infected population and this appears to be related to end-organ diseases collectively referred to as Serious Non-AIDS Events (SNAEs). Circulating miRNAs are reported as promising biomarkers for a number of human disease conditions including those that constitute SNAEs. Our study sought to investigate the potential of selected miRNAs in predicting mortality in HIV-1 infected ART treated individuals. Materials and Methods: A set of miRNAs was chosen based on published associations with human disease conditions that constitute SNAEs. This case: control study compared 126 cases (individuals who died whilst on therapy), and 247 matched controls (individuals who remained alive). Cases and controls were ART treated participants of two pivotal HIV-1 trials. The relative abundance of each miRNA in serum was measured, by RTqPCR. Associations with mortality (all-cause, cardiovascular and malignancy) were assessed by logistic regression analysis. Correlations between miRNAs and CD4+ T cell count, hs-CRP, IL-6 and D-dimer were also assessed. Results: None of the selected miRNAs was associated with all-cause, cardiovascular or malignancy mortality. The levels of three miRNAs (miRs -21, -122 and -200a) correlated with IL-6 while miR-21 also correlated with D-dimer. Additionally, the abundance of miRs -31, -150 and -223, correlated with baseline CD4+ T cell count while the same three miRNAs plus miR- 145 correlated with nadir CD4+ T cell count. Discussion: No associations with mortality were found with any circulating miRNA studied. These results cast doubt onto the effectiveness of circulating miRNA as early predictors of mortality or the major underlying diseases that contribute to mortality in participants treated for HIV-1 infection
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