884 research outputs found

    The Carbon_h-Factor: Predicting Individuals' Research Impact at Early Stages of Their Career

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    Assessing an individual's research impact on the basis of a transparent algorithm is an important task for evaluation and comparison purposes. Besides simple but also inaccurate indices such as counting the mere number of publications or the accumulation of overall citations, and highly complex but also overwhelming full-range publication lists in their raw format, Hirsch (2005) introduced a single figure cleverly combining different approaches. The so-called h-index has undoubtedly become the standard in scientometrics of individuals' research impact (note: in the present paper I will always use the term “research impact” to describe the research performance as the logic of the paper is based on the h-index, which quantifies the specific “impact” of, e.g., researchers, but also because the genuine meaning of impact refers to quality as well). As the h-index reflects the number h of papers a researcher has published with at least h citations, the index is inherently positively biased towards senior level researchers. This might sometimes be problematic when predictive tools are needed for assessing young scientists' potential, especially when recruiting early career positions or equipping young scientists' labs. To be compatible with the standard h-index, the proposed index integrates the scientist's research age (Carbon_h-factor) into the h-index, thus reporting the average gain of h-index per year. Comprehensive calculations of the Carbon_h-factor were made for a broad variety of four research-disciplines (economics, neuroscience, physics and psychology) and for researchers performing on three high levels of research impact (substantial, outstanding and epochal) with ten researchers per category. For all research areas and output levels we obtained linear developments of the h-index demonstrating the validity of predicting one's later impact in terms of research impact already at an early stage of their career with the Carbon_h-factor being approx. 0.4, 0.8, and 1.5 for substantial, outstanding and epochal researchers, respectively

    Asymptotic normality of the Parzen-Rosenblatt density estimator for strongly mixing random fields

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    We prove the asymptotic normality of the kernel density estimator (introduced by Rosenblatt (1956) and Parzen (1962)) in the context of stationary strongly mixing random fields. Our approach is based on the Lindeberg's method rather than on Bernstein's small-block-large-block technique and coupling arguments widely used in previous works on nonparametric estimation for spatial processes. Our method allows us to consider only minimal conditions on the bandwidth parameter and provides a simple criterion on the (non-uniform) strong mixing coefficients which do not depend on the bandwith.Comment: 16 page

    Absolute Spectrally Continuous Stellar Irradiance Calibration in the Infrared

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    Exploring the financial and investment implications of the Paris Agreement

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    A global energy transition is underway. Limiting warming to 2°C (or less), as envisaged in the Paris Agreement, will require a major diversion of scheduled investments in the fossil-fuel industry and other high-carbon capital infrastructure towards renewables, energy efficiency, and other low or negative carbon technologies. The article explores the scale of climate finance and investment needs embodied in the Paris Agreement. It reveals that there is little clarity in the numbers from the plethora of sources (official and otherwise) on climate finance and investment. The article compares the US100billiontargetintheParisAgreementwitharangeofotherfinancialmetrics,suchasinvestment,incrementalinvestment,energyexpenditure,energysubsidies,andwelfarelosses.WhiletherelativelynarrowlydefinedclimatefinanceincludedintheUS100 billion target in the Paris Agreement with a range of other financial metrics, such as investment, incremental investment, energy expenditure, energy subsidies, and welfare losses. While the relatively narrowly defined climate finance included in the US100 billion figure is a fraction of the broader finance and investment needs of climate-change mitigation and adaptation, it is significant when compared to some estimates of the net incremental costs of decarbonization that take into account capital and operating cost savings. However, even if the annual US$100 billion materializes, achieving the much larger implied shifts in investment will require the enactment of long-term internationally coordinated policies, far more stringent than have yet been introduced.</i

    Energy efficiency and renewables

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    The debate between exponents of 'supply side' and 'demand side' approaches to dealing with environmental problems like climate change can sometimes become polarised. At one extreme it is sometimes claimed that the potential for energy efficiency and demands reductions is so large that we hardly need to worry about the supply side. At the other extreme it is sometimes claimed that the potential for renewables is so large that we can forget about energy conservation. This paper looks at how these views stand up in the context of both short and long term sustainable energy policy and seeks a pragmatic strategic compromise

    Critical success factors for embedding carbon management in organizations: lessons from the UK higher education sector

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    Organizations are under increasing pressure from governments and stakeholders to reduce carbon emissions from their business operations for climate change mitigation. Universities are not exempt from this challenge and are operating in a complex external environment, not least responding to the UK government's Climate Change Act 2008 (80% carbon reductions by 2050 as per 1990 baseline). In 2012–2013, the UK Higher Education (HE) sector consumed 7.9 billion kWh of energy and produced 2.3 million tonnes of carbon emissions. This indicates the scale of the challenge and carbon management is central to reduce carbon emissions. However, effective processes for implementing and embedding carbon management in organizations in general, and universities in particular, have yet to be realized. This paper explores the critical success factors (CSFs) for embedding carbon management in universities and, more widely, in organizations. This exploratory study adopted a mixed-methods approach including the content analysis of universities' carbon management plans alongside semi-structured interviews in the UK HE sector. The paper identifies six key factors for successfully embedding carbon management that are pertinent not just for the HE sector, but to organizations broadly: senior management leadership; funding and resources; stakeholder engagement; planning; governance and management; and evaluation and reporting

    Nitrogen abundances in Planet-harbouring stars

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    We present a detailed spectroscopic analysis of nitrogen abundances in 91 solar-type stars, 66 with and 25 without known planetary mass companions. All comparison sample stars and 28 planet hosts were analysed by spectral synthesis of the near-UV NH band at 3360 \AA observed at high resolution with the VLT/UVES,while the near-IR NI 7468 \AA was measured in 31 objects. These two abundance indicators are in good agreement. We found that nitrogen abundance scales with that of iron in the metallicity range -0.6 <[Fe/H]< +0.4 with the slope 1.08 \pm 0.05. Our results show that the bulk of nitrogen production at high metallicities was coupled with iron. We found that the nitrogen abundance distribution in stars with exoplanets is the high [Fe/H] extension of the curve traced by the comparison sample of stars with no known planets. A comparison of our nitrogen abundances with those available in the literature shows a good agreement.Comment: 15 pages, 7 figures, Accepted for publication in A&

    Galactic Evolution of Nitrogen

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    We present detailed spectroscopic analysis of nitrogen abundances in 31 unevolved metal-poor stars analysed by spectral synthesis of the near-UV NH band at 3360 A observed at high resolution with various telescopes. We found that [N/Fe] scales with that of iron in the metallicity range -3.1 < [Fe/H] <0 with the slope 0.01+-0.02. Furthermore, we derive uniform and accurate (N/O) ratios using oxygen abundances from near-UV OH lines obtained in our previous studies. We find that a primary component of nitrogen is required to explain the observations. The NH lines are discovered in the VLT/UVES spectra of the very metal-poor subdwarfs G64-12 and LP815-43 indicating that these stars are N rich. The results are compared with theoretical models and observations of extragalactic HII regions and Damped Lyα\alpha systems. This is the first direct comparison of the (N/O) ratios in these objects with those in Galactic stars.Comment: 10 pages, 6 figures, to appear in Astronomy and Astrophysic

    Early Galactic Evolution of Carbon, Nitrogen and Oxygen

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    We present results on carbon, nitrogen, and oxygen abundances for a sample of unevolved metal-poor stars with metallicities in the range -0.3< [Fe/H]< -3. Oxygen abundances derived from different indicators are compared showing consistently that in the range 0.3 >[Fe/H]>-3.0, the [O/Fe] ratio increases from approximately 0 to 1. We find a good agreement between abundances based on the forbidden line, the OH and IR triplet lines when gravities based on Hipparcos} parallaxes are considered for the sample stars. Gravities derived from LTE ionization balance in metal-poor stars with [Fe/H]< -1 are likely too low, and could be responsible for an underestimation of the oxygen abundances derived using the [OI] line. [C/Fe] and [N/Fe] ratios appear to be constant, independently of metallicity, in the same range. However, they show larger scatter than oxygen at a given metallicity, which could reflect the larger variety of stellar production sites for these other elements.Comment: 10 pages, 3 figures, To appear in the proceedings of the conference "The Chemical Evolution of The Milky Way: Stars versus Clusters", eds. F. Matteucci and F. Giovannelli, Vulcano, Italy, September 20-24 199
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