534 research outputs found

    Absorption of nutrients by grapevine under field conditions

    Get PDF
    From a well fertilized 7 years-old vineyard var. 'Niagara Rosada' (Vinis labrusca L. X Vitis vinifera L.). situated on an Entisol at country of Jundiaí, SP, Brazil, plants were harvested every fifteen days up to 150 days. The plants were divided into: terminal and basal leaves, terminal and basal shoots, and canes, as well grapes. The plant material was analysed by conventional methods for B, Cu, Fe, Mn and Zn. The research was conducted in order: a. to obtain data on the absorption and distribution of the nutrients by the grapevine; b. to obtain data on the exportation of nutrients by the shoots and by the grapes. Conclusions: The leaves present always a higher concentration in nutrients than the other parts of the plant. The leaves, shoots and grapes present different concentrations of the nutrients during the year. The maximum absorption by the leaves, shoots and grapes in mg per plant was observed at the following age (days): The grapevine exported by shoots (pruned) and by grapes the following quantities of nutrients in mg per plant: A vineyeard of 5,000 plants per hectare contains the following quantitites of nutrients: B = 145.45 g.; Cu = 33.60 g.; Fe = 588.85 g.; Mn = 4,093,35 g.; Za = 373.30 g.Ensaio foi conduzido com viderias da cultivar 'Niagara Rosada' (Vitis labrusca L. X Vitis vinifera L.) com 7 anos de idade, no município de Jundiaí, SP, (23°12' de latitude sul e 46°33' de longitude oeste e 715 m de altitude), situadas sobre um Regossolo unidade Currupira, com os objetivos de: (1) determinar as quantidades de nutrientes absorvidos pela videira nos diferentes estádios de desenvolvimento; (2) avaliar a exportação de nutrientes pela cultura durante um ciclo vegetativo. Após a brotação da videira, foram realizadas 17 coletas quinzenais de material. Foram coletadas e separadas as folhas das partes terminal e basal, sarmentos das partes terminal e basal e cachos. No material coletado foram determinados os teores de micronutrientes, com exceção do molibdênio e cloro. Curvas representativas das concentraçoes dos nutrientes nas partes da planta, em função da idade, foram obtidas a partir dos dados calculados através de equações de regressão. Pelos pontos de máximo estimaram-se as quantidades máximas de nutrientes extraídos. Concluiu-se que: - A concentração dos nutrientes é sempre maior nas folhas do que nos sarmentos e existem diferenças nas concentrações de nutrientes das folhas, sarmentos e cachos, em função da idade. - Os acúmulos máximos de nutrientes nas folhas, sarmentos e cachos ocorrem nas seguintes idades: - A exportação de nutrientes em mg por planta pelos cachos e sarmentos removidos pelas colheitas e poda é a seguinte

    Acúmulo de nitrogênio, fósforo, potássio, cálcio, magnésio e enxofre pela videira (Vitis labrusca L. X Vitis vinifera L.) cv. 'Niágara rosada', durante um ciclo vegetativo

    Get PDF
    Plant material from a well fertilized 7 years-old vineyard var. 'Niagara Rosada' (Vitis labrusca L. X Vitis vinifera L.), situated on an Entisol at country of Jundiai, SP, Brazil, was harvested every fifteen days up to 150 days. The plants were divided into: terminal and basal leaves, terminal and basal shoots, and canes, as well grapes. The plant material was analysed by conventional methods for N, P, K, Ca, Mg, S. The research was conducted in order: a. to obtain information on the accumulation of dry matter, during a period of one year; b. to obtain data on the absorption and distribuition of the nutrients by the grapevine; c. to obtain data on the exportation of nutrients by the shoots and by the grapes. Conclusions : The maximum accumulation of the dry matter took place at the age of 148 days. The leaves present always a higher concentration in nutrients than the other parts of the plant. The leaves, shoots and grapes present different concentration of the nutrients during the year. The maximun absorption by the leaves, shoots and grapes in mg per plant was observed at the following age (days): The grapevine exported by shoots (pruned) and by grapes the following quantities of nutrients in mg per plant: A vineyeard of 5.000 plants per hectare content the following quantities of nutrients: N: 90.85 kg; P:28.40 kg; K: 97.60 kg; Ca: 41.20 kg; Mg: 8.10 kg; S: 9.30 kg.Ensaio foi conduzido com videiras de cultivar 'Niagara Rosada' (Vitis labrusca L. X Vitis vinifeva L.) com 7 anos de idade, no município de Jundiaí, SP (23°12' de latitude sul e 46º33' de longitude oeste e 715 m de altitude), situadas sobre um Regossolo unidade Currupira, com os objetivos de: (1) analisar o crescimento (produção de materia seca); (2) determinar as quantidades de nutrientes absorvidos pela videira nos diferentes estádios de desenvolvimento e (3) avaliar a exportação de nutrientes pela cultura durante o ciclo vegetativo. Após a brotação da videira, foram realizadas 17 coletas quinzenais de material. Foram coletadas e separadas as folhas das partes terminal e basal, sarmentos das partes terminal e basal e cachos. No material coletado foram determinados os teores de N, P, K, Ca, Mg e S. Curvas representativas dos acúmulos de matéria seca e das concentrações dos nutrientes nas partes da planta, em função da idade, foram obtidas a partir dos dados calculados através de equações de regressão. Pelos pontos de máximo estimaram-se a produção maxima de matéria seca e as quantidades de nutrientes extraídos. Conclui-se que: . A produção maxima de materia seca ocorre aos 148 dias. . A concentração dos nutrientes é sempre maior nas folhas do que nos sarmentos e existem diferenças nas concentrações de nutrientes das folhas, sarmentos e cachos, em função da idade. . Os acúmulos máximos de nutrientes nas folhas, sarmentos e cachos ocorrem nas seguintes idades

    Overview of Plasma Lens Experiments and Recent Results at SPARC_LAB

    Get PDF
    Beam injection and extraction from a plasma module is still one of the crucial aspects to solve in order to produce high quality electron beams with a plasma accelerator. Proper matching conditions require to focus the incoming high brightness beam down to few microns size and to capture a high divergent beam at the exit without loss of beam quality. Plasma-based lenses have proven to provide focusing gradients of the order of kT/m with radially symmetric focusing thus promising compact and affordable alternative to permanent magnets in the design of transport lines. In this paper an overview of recent experiments and future perspectives of plasma lenses is reported

    Measuring Black Hole Spin using X-ray Reflection Spectroscopy

    Full text link
    I review the current status of X-ray reflection (a.k.a. broad iron line) based black hole spin measurements. This is a powerful technique that allows us to measure robust black hole spins across the mass range, from the stellar-mass black holes in X-ray binaries to the supermassive black holes in active galactic nuclei. After describing the basic assumptions of this approach, I lay out the detailed methodology focusing on "best practices" that have been found necessary to obtain robust results. Reflecting my own biases, this review is slanted towards a discussion of supermassive black hole (SMBH) spin in active galactic nuclei (AGN). Pulling together all of the available XMM-Newton and Suzaku results from the literature that satisfy objective quality control criteria, it is clear that a large fraction of SMBHs are rapidly-spinning, although there are tentative hints of a more slowly spinning population at high (M>5*10^7Msun) and low (M<2*10^6Msun) mass. I also engage in a brief review of the spins of stellar-mass black holes in X-ray binaries. In general, reflection-based and continuum-fitting based spin measures are in agreement, although there remain two objects (GROJ1655-40 and 4U1543-475) for which that is not true. I end this review by discussing the exciting frontier of relativistic reverberation, particularly the discovery of broad iron line reverberation in XMM-Newton data for the Seyfert galaxies NGC4151, NGC7314 and MCG-5-23-16. As well as confirming the basic paradigm of relativistic disk reflection, this detection of reverberation demonstrates that future large-area X-ray observatories such as LOFT will make tremendous progress in studies of strong gravity using relativistic reverberation in AGN.Comment: 19 pages. To appear in proceedings of the ISSI-Bern workshop on "The Physics of Accretion onto Black Holes" (8-12 Oct 2012). Revised version adds a missing source to Table 1 and Fig.6 (IRAS13224-3809) and corrects the referencing of the discovery of soft lags in 1H0707-495 (which were in fact first reported in Fabian et al. 2009

    Theoretical overview on high-energy emission in microquasars

    Get PDF
    Microquasar (MQ) jets are sites of particle acceleration and synchrotron emission. Such synchrotron radiation has been detected coming from jet regions of different spatial scales, which for the instruments at work nowadays appear as compact radio cores, slightly resolved radio jets, or (very) extended structures. Because of the presence of relativistic particles and dense photon, magnetic and matter fields, these outflows are also the best candidates to generate the very high-energy (VHE) gamma-rays detected coming from two of these objects, LS 5039 and LS I +61 303, and may be contributing significantly to the X-rays emitted from the MQ core. In addition, beside electromagnetic radiation, jets at different scales are producing some amount of leptonic and hadronic cosmic rays (CR), and evidences of neutrino production in these objects may be eventually found. In this work, we review on the different physical processes that may be at work in or related to MQ jets. The jet regions capable to produce significant amounts of emission at different wavelengths have been reduced to the jet base, the jet at scales of the order of the size of the system orbital semi-major axis, the jet middle scales (the resolved radio jets), and the jet termination point. The surroundings of the jet could be sites of multiwavelegnth emission as well, deserving also an insight. We focus on those scenarios, either hadronic or leptonic, in which it seems more plausible to generate both photons from radio to VHE and high-energy neutrinos. We briefly comment as well on the relevance of MQ as possible contributors to the galactic CR in the GeV-PeV range.Comment: Astrophysics & Space Science, in press (invited talk in the conference: The multimessenger approach to the high-energy gamma-ray sources", Barcelona/Catalonia, in July 4-7); 10 pages, 6 figures, 2 tables (one reference corrected

    Project momo: Multiwavelength observations and modeling of oj 287

    Get PDF
    Our project MOMO (Multiwavelength observations and modeling of OJ 287) consists of dedicated, dense, long-term flux and spectroscopic monitoring, and deep follow-up observations of the blazar OJ 287 at >13 frequencies from the radio to the X-ray band since late 2015. In particular, we are using Swift to obtain optical-UV-X-ray spectral energy distributions (SEDs) and the Effelsberg telescope to obtain radio measurements between 2 and 40 GHz. MOMO is the densest long-term monitoring of OJ 287 involving X-rays and broad-band SEDs. The theoretical part of the project aims at understanding jet and accretion physics of the blazar central engine in general and the supermassive binary black hole scenario in particular. Results are presented in a sequence of publications and so far included: detection and detailed analysis of the bright 2016/17 and 2020 outbursts and the long-term light curve; Swift, XMM, and NuSTAR spectroscopy of the 2020 outburst around maximum; and interpretation of selected events in the context of the binary black hole scenario of OJ 287 (papers I–IV). Here, we provide a description of the project MOMO, a summary of previous results, the latest results, and we discuss future prospects. View Full-TextKeywords: active galactic nuclei; blazars; jets; black holes; supermassive binary black holes; OJ 287; spectral energy distributions; Neil Gehrels Swift observatory; XMM-Newton; NuSTAR</p

    Relationships of Sleep Duration, Midpoint, and Variability with Physical Activity in the HCHS/SOL Sueño Ancillary Study

    Get PDF
    Objective/Background: Short and long sleep duration, later sleep midpoint, and greater intra-individual sleep variability are associated with lower physical activity, but previous research lacks objective and concurrent assessment of sleep and physical activity. This cross-sectional study examined whether sleep duration, midpoint, and variability in duration and midpoint were related to wrist actigraphy-measured physical activity. Participants: Participants were 2156 Hispanics/Latinos in the Hispanic Community Health Study/Study of Latinos (HCHS/SOL) Sueño Ancillary Study. Methods: Participants wore Actiwatch devices to measure sleep and physical activity via the wrist for ≥5 days. Physical activity was defined as minutes/day in the upper quartile of the sampling distribution’s non-sleep activity, capturing light to vigorous physical activity. Results: An inverse linear relationship between sleep duration and physical activity was found such that each additional sleep hour related to 29 fewer minutes of physical activity (B = −28.7, SE = 3.8), p <.01). Variability in sleep midpoint was also associated with physical activity; with each 1-hr increase in variability there were 24 more minutes of physical activity (B = 24.2, SE = 5.6, p <.01). In contrast, sleep midpoint and variability in duration were not associated with physical activity. Sensitivity analyses identified an association of short sleep duration and greater variability in sleep duration with greater accelerometry-derived moderate-to-vigorous physical activity measured at the HCHS/SOL baseline (M = 2.1 years before the sleep assessment). Conclusions: Findings help clarify inconsistent prior research associating short sleep duration and sleep variability with greater health risks but also contribute novel information with simultaneous objective assessments

    Black Hole Spin via Continuum Fitting and the Role of Spin in Powering Transient Jets

    Full text link
    The spins of ten stellar black holes have been measured using the continuum-fitting method. These black holes are located in two distinct classes of X-ray binary systems, one that is persistently X-ray bright and another that is transient. Both the persistent and transient black holes remain for long periods in a state where their spectra are dominated by a thermal accretion disk component. The spin of a black hole of known mass and distance can be measured by fitting this thermal continuum spectrum to the thin-disk model of Novikov and Thorne; the key fit parameter is the radius of the inner edge of the black hole's accretion disk. Strong observational and theoretical evidence links the inner-disk radius to the radius of the innermost stable circular orbit, which is trivially related to the dimensionless spin parameter a_* of the black hole (|a_*| < 1). The ten spins that have so far been measured by this continuum-fitting method range widely from a_* \approx 0 to a_* > 0.95. The robustness of the method is demonstrated by the dozens or hundreds of independent and consistent measurements of spin that have been obtained for several black holes, and through careful consideration of many sources of systematic error. Among the results discussed is a dichotomy between the transient and persistent black holes; the latter have higher spins and larger masses. Also discussed is recently discovered evidence in the transient sources for a correlation between the power of ballistic jets and black hole spin.Comment: 30 pages. Accepted for publication in Space Science Reviews. Also to appear in hard cover in the Space Sciences Series of ISSI "The Physics of Accretion onto Black Holes" (Springer Publisher). Changes to Sections 5.2, 6.1 and 7.4. Section 7.4 responds to Russell et al. 2013 (MNRAS, 431, 405) who find no evidence for a correlation between the power of ballistic jets and black hole spi

    Diabetes, cognitive decline, and mild cognitive impairment among diverse Hispanics/ Latinos: Study of Latinos–Investigation of neurocognitive aging results (HCHS/SOL)

    Get PDF
    OBJECTIVE Hispanics/Latinos are the largest ethnic/racial group in the U.S., have the highest prevalence of diabetes, and are at increased risk for neurodegenerative disorders. Currently, little is known about the relationship between diabetes and cognitive decline and disorders among diverse Hispanics/Latinos. The purpose of this study is to clarify these relationships in diverse middle-aged and older Hispanics/Latinos. RESEARCH DESIGN AND METHODS The Study of Latinos–Investigation of Neurocognitive Aging (SOL-INCA) is an ancillary study of the Hispanic Community Health Study/Study of Latinos (HCHS/SOL). HCHS/ SOL is a multisite (Bronx, NY; Chicago, IL; Miami, FL; and San Diego, CA), probability-sampled (i.e., representative of targeted populations), and prospective cohort study. Between 2016 and 2018, SOL-INCA enrolled diverse Hispanics/Latinos aged ‡50 years (n 5 6,377). Global cognitive decline and mild cognitive impairment (MCI) were the primary outcomes. RESULTS Prevalent diabetes at visit 1, but not incident diabetes at visit 2, was associated with significantly steeper global cognitive decline (bGC 5 20.16 [95% CI 20.25; 20.07]; P &lt; 0.001), domain-specific cognitive decline, and higher odds of MCI (odds ratio 1.74 [95% CI 1.34; 2.26]; P &lt; 0.001) compared with no diabetes in age- and sex-adjusted models. CONCLUSIONS Diabetes was associated with cognitive decline and increased MCI prevalence among diverse Hispanics/Latinos, primarily among those with prevalent diabetes at visit 1. Our findings suggest that significant cognitive decline and MCI may be considered additional disease complications of diabetes among diverse middle-aged and older Hispanics/Latinos
    corecore