2,756 research outputs found

    Capability of the Invasive Tree Prosopis glandulosa Torr. to Remediate Soil Treated with Sewage Sludge

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    Sewage sludge improves agricultural soil and plant growth, but there are hazards associated with its use, including high metal(loid) contents. An experimental study was conducted under greenhouse conditions to examine the effects of sewage sludge on growth of the invasive tree Prosopis glandulosa, as well as to determine its phytoremediation capacity. Plants were established and grown for seven months along a gradient of sewage sludge content. Plant traits, soil properties, and plant and soil concentrations of N, P, K, Cd, Pb, Cu, Ni, Zn, Cr, Co, As, and Fe were recorded. The addition of sewage sludge led to a significant decrease in soil pH, and Ni, Co, and As concentrations, as well as an increase in soil organic matter and the concentrations of N, P, Cu, Zn, and Cr. Increasing sewage sludge content in the growth medium raised the total uptake of most metals by P. glandulosa plants due to higher biomass accumulation (taller plants with more leaves) and higher metal concentrations in the plant tissues. P. glandulosa concentrated more Cd, Pb, Cu, Zn, and Fe in its below-ground biomass (BGB) than in its above-ground biomass (AGB). P. glandulosa concentrated Ni, Co, and As in both BGB and AGB. P. glandulosa has potential as a biotool for the phytoremediation of sewage sludges and sewage-amended soils in arid and semi-arid environments, with a potential accumulation capability for As in plant leaves

    The Role of Sustainability in Brand Equity Value in the Financial Sector

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    The behavior of firms is changing as new kinds of businesses evolve. In particular, companies are now seeking to optimize their value, especially their intangible value¿referred to as brand equity value¿which has many behavioral drivers. The analysis of brand equity determinants in the financial sector (e.g., ethical investments, sustainability and firm behavior) has received little attention. The methodology used in this study included the collection of information from publicly listed companies, followed by the execution of a statistical analysis to study the correlations between brand equity values and their determinants. We aimed to close this gap by raising the awareness of the positive impacts of sustainable investments in the financial sector and the need for a managerial implementation model to build a sustainability-oriented brand value. The objective of this research was to examine the relationships between elements such as sustainability scores or diversity measures and firms' brand value. Considering sectoral and regional effects, we observed a positive relationship between environmental and social governance scores and brand equity value

    National policy-makers speak out: are researchers giving them what they need?

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    The objective of this empirical study was to understand the perspectives and attitudes of policy-makers towards the use and impact of research in the health sector in low- and middle-income countries. The study used data from 83 semi-structured, in-depth interviews conducted with purposively selected policy-makers at the national level in Argentina, Egypt, Iran, Malawi, Oman and Singapore. The interviews were structured around an interview guide developed based on existing literature and in consultation with all six country investigators. Transcripts were processed using a thematic-analysis approach. Policy-makers interviewed for this study were unequivocal in their support for health research and the high value they attribute to it. However, they stated that there were structural and informal barriers to research contributing to policy processes, to the contribution research makes to knowledge generally, and to the use of research in health decision-making specifically. Major findings regarding barriers to evidence-based policy-making included poor communication and dissemination, lack of technical capacity in policy processes, as well as the influence of the political context. Policy-makers had a variable understanding of economic analysis, equity and burden of disease measures, and were vague in terms of their use in national decisions. Policy-maker recommendations regarding strategies for facilitating the uptake of research into policy included improving the technical capacity of policy-makers, better packaging of research results, use of social networks, and establishment of fora and clearinghouse functions to help assist in evidence-based policy-makin

    Electronically Controllable Phase Shifter with Progressive Impedance Transformation at K Band

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    This communication presents the design of a two-port electronically tunable phase shifter at K band. The phase shifter consists of a 3 dB hybrid coupler loaded with reflective phase-controllable circuits. The reflective circuits are formed by varactors and non-sequential impedance transformers which increase the operational bandwidth and the provided phase shift. The final phase shifter design is formed by two loaded-coupler stages of phase shifting to guarantee a complete phase turn. An 18 GHz phase shifter design with dynamic range of 600 degrees of phase shift is depicted in this document. The prototype is manufactured and validated through measurements showing good agreement with the simulation results.This work has been partially supported by the TIN2016-75097-P, RTI2018-102002-A-I00, and EQC2018- 004988-P projects of the Spanish National Program of Research, Development, and Innovation and project B-TIC-402-UGR18 of Junta de Andalucí

    Supernova progenitor stars in the initial range of 23 to 33 solar masses and their relation with the SNR Cas A

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    Multi wavelength observations of Cassiopeia A (Cas A) have provided us with a strong evidence for the presence of circumstellar material surrounding the progenitor star. It has been suggested that its progenitor was a massive star with a strong mass loss. But, despite the large amount of observational data from optical, IR, radio and x-ray observations, the identity of Cas A progenitor is still elusive. In this work, we compute stellar and circumstellar numerical models to look for the progenitor of Cas A. The models will be compared with the observational constraints. We have computed stellar evolution models to get time-dependent wind parameters and surface abundances. We have chosen a set of probable progenitor stars, with initial masses of 23, 28, 29, 30 and 33 \Mo, with mass loss. The derived mass loss rates and wind terminal velocities are used to simulate the evolution of the circumstellar medium. Our stellar set gives distinct SN progenitors: RSG, luminous blue super giants (LBSGs) and Wolf-Rayet (WR) stars. The 23 \Mo star explodes as a RSG in a ρr2\rm \rho \sim r^{-2} dense, free streaming wind surrounded by a thin, compressed, RSG shell. The 28 \Mo star explodes as a LBSG, and the SN blast wave interacts with a low density, free streaming wind surrounded by an unstable and massive ''RSG+LBSG'' shell. Finally, the 30 and 33 \Mo stars explode as WR stars surrounded by fast, WR winds that terminate in highly fragmented ''WR+RSG shell''. We have compared the surface chemical abundances of our stellar models with the observational abundances in Cas A. The abundance analysis shows that the progenitor was a star with an initial mass of the order of 30 \Mo, while the hydrodynamical analysis favors progenitors of initial masses around 23.Comment: 12 pages, 11 figures, accepted for publication in Astronomy & Astrophysic

    Does inter-vertebral range of motion increase after spinal manipulation? A prospective cohort study.

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    Background: Spinal manipulation for nonspecific neck pain is thought to work in part by improving inter-vertebral range of motion (IV-RoM), but it is difficult to measure this or determine whether it is related to clinical outcomes. Objectives: This study undertook to determine whether cervical spine flexion and extension IV-RoM increases after a course of spinal manipulation, to explore relationships between any IV-RoM increases and clinical outcomes and to compare palpation with objective measurement in the detection of hypo-mobile segments. Method: Thirty patients with nonspecific neck pain and 30 healthy controls matched for age and gender received quantitative fluoroscopy (QF) screenings to measure flexion and extension IV-RoM (C1-C6) at baseline and 4-week follow-up between September 2012-13. Patients received up to 12 neck manipulations and completed NRS, NDI and Euroqol 5D-5L at baseline, plus PGIC and satisfaction questionnaires at follow-up. IV-RoM accuracy, repeatability and hypo-mobility cut-offs were determined. Minimal detectable changes (MDC) over 4 weeks were calculated from controls. Patients and control IV-RoMs were compared at baseline as well as changes in patients over 4 weeks. Correlations between outcomes and the number of manipulations received and the agreement (Kappa) between palpated and QF-detected of hypo-mobile segments were calculated. Results: QF had high accuracy (worst RMS error 0.5o) and repeatability (highest SEM 1.1o, lowest ICC 0.90) for IV-RoM measurement. Hypo-mobility cut offs ranged from 0.8o to 3.5o. No outcome was significantly correlated with increased IV-RoM above MDC and there was no significant difference between the number of hypo-mobile segments in patients and controls at baseline or significant increases in IV-RoMs in patients. However, there was a modest and significant correlation between the number of manipulations received and the number of levels and directions whose IV-RoM increased beyond MDC (Rho=0.39, p=0.043). There was also no agreement between palpation and QF in identifying hypo-mobile segments (Kappa 0.04-0.06). Conclusions: This study found no differences in cervical sagittal IV-RoM between patients with non-specific neck pain and matched controls. There was a modest dose-response relationship between the number of manipulations given and number of levels increasing IV-RoM - providing evidence that neck manipulation has a mechanical effect at segmental levels. However, patient-reported outcomes were not related to this
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