1,982 research outputs found
THE MUNICIPALITY AS A UNIT IN RATEMAKING AND CONFISCATION CASES
The recent decision of the Supreme Court of the United States in the so-called Martinsville case has been interpreted by some critics as laying down a municipal unit doctrine of rate making, denying to a system utility the right to earn from its entire operations a fair return on the value of its entire property, and substituting therefor a bundle of rights to earn in each municipality served a fair return on the value of the property used and useful therefor
Noncooperatively Optimized Tolerance: Decentralized Strategic Optimization in Complex Systems
We introduce noncooperatively optimized tolerance (NOT), a generalization of
highly optimized tolerance (HOT) that involves strategic (game theoretic)
interactions between parties in a complex system. We illustrate our model in
the forest fire (percolation) framework. As the number of players increases,
our model retains features of HOT, such as robustness, high yield combined with
high density, and self-dissimilar landscapes, but also develops features of
self-organized criticality (SOC) when the number of players is large enough.
For example, the forest landscape becomes increasingly homogeneous and
protection from adverse events (lightning strikes) becomes less closely
correlated with the spatial distribution of these events. While HOT is a
special case of our model, the resemblance to SOC is only partial; for example,
the distribution of cascades, while becoming increasingly heavy-tailed as the
number of players increases, also deviates more significantly from a power law
in this regime. Surprisingly, the system retains considerable robustness even
as it becomes fractured, due in part to emergent cooperation between
neighboring players. At the same time, increasing homogeneity promotes
resilience against changes in the lightning distribution, giving rise to
intermediate regimes where the system is robust to a particular distribution of
adverse events, yet not very fragile to changes
Correction to: Solvent free synthesis of PdZn/TiO2 catalysts for the hydrogenation of CO2 to methanol
The article Solvent Free Synthesis of PdZn/TiO2 Catalysts for the Hydrogenation of CO2 to Methanol by Hasliza Bahruji, Jonathan Ruiz Esquius, Michael Bowker, Graham Hutchings, Robert D. Armstrong, Wilm Jones was originally published Online First without open access. After publication in volume 61, issue 3–4, pages 144–153, the author decided to opt for Open Choice and to make the article an open access publication. Therefore, the copyright of the article has been changed to ©The Author(s) 2018 and the article is forthwith distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits use, duplication, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made
Where are the paediatricians? An international survey to understand the global paediatric workforce
Objective: Our primary objective was to examine the global paediatric workforce and to better understand geographic differences in the number of paediatricians globally. Secondary objectives were to describe paediatric workforce expectations, who provides children with preventative care and when children transition out of paediatric care. Design: Survey of identified paediatric leaders in each country. Setting: Paediatric association leaders worldwide. Main outcome measures: Paediatrician numbers, provision of primary care for children, age of transition to adult care. Results: Responses were obtained from 121 countries (73% of countries approached). The number of paediatricians per 100 000 children ranged from a median of 0.5 (IQR 0.3–1.4) in low-income countries to 72 (IQR 4–118) in high-income countries. Africa and South-East Asia reported the lowest paediatrician density (median of 0.8 paediatricians per 100 000 children, IQR 0.4–2.6 and median of 4, IQR 3–9, respectively) and fewest paediatricians entering the workforce. 82% of countries reported transition to adult care by age 18% and 39% by age 15. Most countries (91%) but only 64% of low-income countries reported provision of paediatric preventative care (p\u3c0.001, Cochran-Armitage trend test). Systems of primary care provision varied widely. A majority of countries (63%) anticipated increases in their paediatric workforce in the next decade. Conclusions: Paediatrician density mirrors known inequities in health provider distribution. Fewer paediatricians are entering the workforce in areas with already low paediatrician density, which may exacerbate disparities in child health outcomes. In some regions, children transition to adult care during adolescence, with implications for healthcare training and delivery. Paediatrician roles are heterogeneous worldwide, and country-specific strategies should be used to address inequity in child health provisio
EVM and Achievable Data Rate Analysis of Clipped OFDM Signals in Visible Light Communication
Orthogonal frequency division multiplexing (OFDM) has been considered for
visible light communication (VLC) thanks to its ability to boost data rates as
well as its robustness against frequency-selective fading channels. A major
disadvantage of OFDM is the large dynamic range of its time-domain waveforms,
making OFDM vulnerable to nonlinearity of light emitting diodes (LEDs). DC
biased optical OFDM (DCO-OFDM) and asymmetrically clipped optical OFDM
(ACO-OFDM) are two popular OFDM techniques developed for the VLC. In this
paper, we will analyze the performance of the DCO-OFDM and ACO-OFDM signals in
terms of error vector magnitude (EVM), signal-to-distortion ratio (SDR), and
achievable data rates under both average optical power and dynamic optical
power constraints. EVM is a commonly used metric to characterize distortions.
We will describe an approach to numerically calculate the EVM for DCO-OFDM and
ACO-OFDM. We will derive the optimum biasing ratio in the sense of minimizing
EVM for DCO-OFDM. Additionally, we will formulate the EVM minimization problem
as a convex linear optimization problem and obtain an EVM lower bound against
which to compare the DCO-OFDM and ACO-OFDM techniques. We will prove that the
ACO-OFDM can achieve the lower bound. Average optical power and dynamic optical
power are two main constraints in VLC. We will derive the achievable data rates
under these two constraints for both additive white Gaussian noise (AWGN)
channel and frequency-selective channel. We will compare the performance of
DCO-OFDM and ACO-OFDM under different power constraint scenarios
The selective oxidation of n-butanol to butyraldehyde by oxygen using stable Pt-based nanoparticulate catalysts: an efficient route for upgrading aqueous biobutanol
Supported Pt nanoparticles are shown to be active and selective towards butyraldehyde in the base-free oxidation of n-butanol by O2 in an aqueous phase. The formation of butyric acid as a by-product promoted the leaching of Pt and consequently the activity of the catalysts decreased upon reuse. Characterisation showed that the degree to which Pt leached from the catalysts was related to both the metal–support interaction and metal particle size. A catalyst active and stable (<1% metal leaching) in the aqueous reaction medium was obtained when Pt nanoparticles were supported on activated carbon and prepared by a chemical vapour impregnation method. The presence of n-butanol in the aqueous medium is required to inhibit the over oxidation of butyraldehyde to butyric acid. Consequently, high selectivities towards butyraldehyde can only be obtained at intermediate n-butanol conversion
A hetero-alkali-metal version of the utility amide LDA : lithium-potassium diisopropylamide
Designed to extend the synthetically important alkali-metal diisopropylamide [(NPr2)-Pr-i; DA] class of compounds, the first example of a hetero-alkali-metallic complex of DA has been prepared as a partial TMEDA solvate. Revealed by an X-ray crystallographic study, its structure exists as a discrete lithium-rich trinuclear Li2KN3 heterocycle, with TMEDA only solvating the largest of the alkali-metals, with the two-coordinate lithium atoms being close to linearity [161.9(2)degrees]. A variety of NMR spectroscopic studies, including variable temperature and DOSY NMR experiments, suggests that this new form of LDA maintains its integrity in non-polar hydrocarbon solution. This complex thus represents a rare example of a KDA molecule which is soluble in non-polar medium without the need for excessive amounts of solubilizing Lewis donor being added
Developing lithium chemistry of 1,2-dihydropyridines : from kinetic intermediates to isolable characterized compounds
Generally considered kinetic intermediates in addition reactions of alkyllithiums to pyridine, 1-lithio-2-alkyl-1,2-dihydropyridines have been rarely isolated or characterized. This study develops their "isolated" chemistry. By a unique stoichiometric (that is 1:1, alkyllithium:pyridine ratios) synthetic approach using tridentate donors we show it is possible to stabilize and hence crystallize monomeric complexes where alkyl is tert-butyl. Theoretical calculations probing the donor-free parent tert-butyl species reveal 12 energetically similar stereoisomers in two distinct cyclotrimeric (LiN)3 conformations. NMR studies (including DOSY spectra) and thermal volatility analysis compare new sec-butyl and iso-butyl isomers showing the former is a hexane soluble efficient hydrolithiation agent converting benzophenone to lithium diphenylmethoxide. Emphasizing the criticalness of stoichiometry, reaction of nBuLi/Me6TREN with two equivalents of pyridine results in non-alkylated 1-lithio-1,4-dihydropyridine·Me6TREN and 2-n-butylpyridine, implying mechanistically the kinetic 1,2-n-butyl intermediate hydrolithiates the second pyridine
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