4,748 research outputs found
Magnetic monolayer LiN: Density Functional Theory Calculations
Density functional theory (DFT) calculations are used to investigate the
electronic and magnetic structures of a two-dimensional (2D) monolayer
LiN. It is shown that bulk LiN is a non-magnetic semiconductor. The
non-spinpolarized DFT calculations show that electrons of N in 2D LiN
form a narrow band at the Fermi energy due to a low coordination
number, and the density of states at the Fermi energy ()) is
increased as compared with bulk LiN. The large ) shows
instability towards magnetism in Stoner's mean field model. The spin-polarized
calculations reveal that 2D LiN is magnetic without intrinsic or impurity
defects. The magnetic moment of 1.0\, in 2D LiN is mainly
contributed by the electrons of N, and the band structure shows
half-metallic behavior. {Dynamic instability in planar LiN monolayer is
observed, but a buckled LiN monolayer is found to be dynamically stable.}
The ferromagnetic (FM) and antiferromagnetic (AFM) coupling between the N atoms
is also investigated to access the exchange field strength. {We found that
planar (buckled) 2D LiN is a ferromagnetic material with Curie
temperature of 161 (572) K.}Comment: Euro Phys. Lett. 2017 (Accepted
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Integrated Arable Farming Systems and their potential uptake in the UK
Integrated Arable Farming Systems are examined from the perspective of the farmer considering the use of such techniques, and data are presented which suggest that the uptake of the approach may expose the manager to a greater degree of risk. Observations are made about the possible uptake of such systems in the UK and the implications this may have for agricultural and environmental policy in general
Iron(III)-catalyzed chlorination of activated arenes
A general and regioselective method for the chlorination of activated arenes has been developed. The transformation uses iron(III) triflimide as a powerful Lewis acid for the activation of N-chlorosuccinimide and the subsequent chlorination of a wide range of anisole, aniline, acetanilide and phenol derivatives. The reaction was utilized for the late-stage mono- and di-chlorination of a range of target compounds such as the natural product nitrofungin, the antibacterial agent chloroxylenol and the herbicide chloroxynil. The facile nature of this transformation was demonstrated with the development of one-pot tandem iron-catalyzed dihalogenation processes allowing highly regioselective formation of different carbon-halogen bonds. The synthetic utility of the resulting dihalogenated aryl compounds as building blocks was established with the synthesis of natural products and pharmaceutically relevant targets
Dirac versus Reduced Quantization of the Poincar\'{e} Symmetry in Scalar Electrodynamics
The generators of the Poincar\'{e} symmetry of scalar electrodynamics are
quantized in the functional Schr\"{o}dinger representation. We show that the
factor ordering which corresponds to (minimal) Dirac quantization preserves the
Poincar\'{e} algebra, but (minimal) reduced quantization does not. In the
latter, there is a van Hove anomaly in the boost-boost commutator, which we
evaluate explicitly to lowest order in a heat kernel expansion using zeta
function regularization. We illuminate the crucial role played by the gauge
orbit volume element in the analysis. Our results demonstrate that preservation
of extra symmetries at the quantum level is sometimes a useful criterion to
select between inequivalent, but nevertheless self-consistent, quantization
schemes.Comment: 24 page
Investigating the Impacts of Cyber-Attacks on Pricing Data of Home Energy Management Systems in Demand Response Programs
© 2018 IEEE. Provision of security involves protecting lives and properties, and properties in this context include data and services. This paper investigates the impact of cyber-attacks on load scheduling applications by simulating various possible modes for these attacks while observing possible effects on the users. The attack modes used are in the form of denial of service (DoS) and phishing attacks whereby the attacker is able to interfere with data intake to the Home Energy Management Systems (HEMS) or a modification of critical data to the HEMS. The dynamic pricing information and load profile data is the target here although other types of data utilized by the central controller for load scheduling purposes can also be targeted. The test-bed uses load scheduling applications based on genetic algorithm optimization. Results show the impact on optimized load profiles and how they can discourage active demand response participation if such attacks are not properly managed.Published versio
Determination of gamma-ray widths in N using nuclear resonance fluorescence
The stable nucleus N is the mirror of O, the bottleneck in the
hydrogen burning CNO cycle. Most of the N level widths below the proton
emission threshold are known from just one nuclear resonance fluorescence (NRF)
measurement, with limited precision in some cases. A recent experiment with the
AGATA demonstrator array determined level lifetimes using the Doppler Shift
Attenuation Method (DSAM) in O. As a reference and for testing the
method, level lifetimes in N have also been determined in the same
experiment. The latest compilation of N level properties dates back to
1991. The limited precision in some cases in the compilation calls for a new
measurement in order to enable a comparison to the AGATA demonstrator data. The
widths of several N levels have been studied with the NRF method. The
solid nitrogen compounds enriched in N have been irradiated with
bremsstrahlung. The -rays following the deexcitation of the excited
nuclear levels were detected with four HPGe detectors. Integrated
photon-scattering cross sections of ten levels below the proton emission
threshold have been measured. Partial gamma-ray widths of ground-state
transitions were deduced and compared to the literature. The photon scattering
cross sections of two levels above the proton emission threshold, but still
below other particle emission energies have also been measured, and proton
resonance strengths and proton widths were deduced. Gamma and proton widths
consistent with the literature values were obtained, but with greatly improved
precision.Comment: Final published version, minor grammar changes, 10 pages, 4 figures,
8 tables; An addendum is published where the last section is revised: T.
Sz\"ucs and P. Mohr, Phys. Rev. C 92, 044328 (2015) [arXiv:1510.04956
Cholate Conjugated Polymeric Amphiphiles as Efficient Artificial Ionophores
A family of amphiphilic copolymers containing hydrophobic cholate pendants has been prepared by copolymerization of cholic acid-based monomer 2-(methacryloxy)-ethyl cholate (MAECA) with polyethylene glycol methyl ether methacrylate (PEGMA). The polymers differ for the content of MAECA that increases from 0 to 35%. The copolymers partition within liposomes and display potent ionophoric activity forming large pores in the membrane and allowing the leakage of small inorganic ions (H+, Na+) and of large polar organic molecules (calcein). Their activity is strictly correlated to the content of cholic acid subunits, increasing as the fraction of cholate moiety increases
Qualitative analysis of essential oil of Rosmarinus officinalis L. cultivated in Uttaranchal Hills, India
Gas chromatography and gas chromatography and mass spectroscopy analysis of essentialoil hydrodistilled from fresh aerial part of rosemary (Rosmarinus officinalis) cultivated inUttaranchal, India, resolved into 33 compounds representing 96.29% of the essential oilaccording to their chromatographic retention indices and mass spectra. The major compoundsof the oil were, camphor (26.40%), 1, 8-cineole (23.40%), α-pinene (9.94%), camphene (5.83%),myrcene (4.86%), bornyl acetate (3.97%), verbenone (3.32%), limonene (3.08%), borneol(2.05%) and α-terpineol (2.68%).
 
Effect of plant growth regulators and activated charcoal on in vitro growth and development of oil palm (Elaeis guineensis Jacq. var. Dura) zygotic embryo
The effect of plant growth regulators and activated charcoal (AC) on in vitro regeneration and plantlet development of oil palm (Elaeis guineensis Jacq. var. Dura) zygotic embryos were assessed. Zygotic embryos were cultured on Murashige and Skoog (MS) medium supplemented with a blend of 0.05 or 0.1 mg/L of each plant growth regulators (PGR) (gibberellic acid, 6-benzlaminopurine and α-naphthaleneacetic acid) without or with 2 g/L AC. The growth and development of the embryos were affected by the types of media formulations. Zygotic embryos cultured on MS medium supplemented with both PGR and AC enhanced shoot initiation and subsequent plantlet development, while PGR supplemented MS media without AC led to abnormal growth, suggesting that AC is indispensable for oil palm plantlet regeneration in vitro. The best medium for growth and development of plantlets was MS medium supplemented with 0.1 mg/L PGR and 2 g/L AC which significantly increased plantlet height (9.4 cm) as well as root length (4.4 cm) than the remaining media formulations.Key words: Activated charcoal, oil palm, plant growth regulators, zygotic embryo
A critical look at studies applying over-sampling on the TPEHGDB dataset
Preterm birth is the leading cause of death among young children and has a large prevalence globally. Machine learning models, based on features extracted from clinical sources such as electronic patient files, yield promising results. In this study, we review similar studies that constructed predictive models based on a publicly available dataset, called the Term-Preterm EHG Database (TPEHGDB), which contains electrohysterogram signals on top of clinical data. These studies often report near-perfect prediction results, by applying over-sampling as a means of data augmentation. We reconstruct these results to show that they can only be achieved when data augmentation is applied on the entire dataset prior to partitioning into training and testing set. This results in (i) samples that are highly correlated to data points from the test set are introduced and added to the training set, and (ii) artificial samples that are highly correlated to points from the training set being added to the test set. Many previously reported results therefore carry little meaning in terms of the actual effectiveness of the model in making predictions on unseen data in a real-world setting. After focusing on the danger of applying over-sampling strategies before data partitioning, we present a realistic baseline for the TPEHGDB dataset and show how the predictive performance and clinical use can be improved by incorporating features from electrohysterogram sensors and by applying over-sampling on the training set
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