Search results for "shift"
showing 10 items of 1226 documents
Online Education and Quality of Life: Universidad de Palermo as a Model of Innovation in Latin America
2019
We are living in a time full of challenges as the Fourth Industrial Revolution unfolds at an unprecedented pace, in an interconnected world which has changed the way we work, the way we communicate, and education can’t be an exception. The boundaries between the physical and digital worlds are becoming more and more blurred, and the convergence of online and face-to-face interaction is becoming ever more evident, with machine learning and artificial intelligence applied to everyday life. Technology is changing the world, and universities must not only adapt to this reality but also innovate and take advantage of it, in order to offer more and better quality education to an increasingly dive…
1H, 13C and 15N NMR spectral and theoretical studies of some methyl and alkylamino derivatives of 4-halopyridine N-oxides
2006
Abstract Nine new and three earlier known 4-halogen (Cl and Br) substituted pyridine N-oxides have been prepared and their 1 H, 13 C and 15 N NMR chemical shifts assigned based on PFG 1 H, X (X= 13 C and 15 N) HMQC and HMBC experiments as well as the comparison with our earlier results for substituted pyridine N-oxide derivatives. The 15 N resonances of the pyridine nitrogen are 27–40 ppm more shielded in 4-halo-2-alkylamino-6-methyl-5-nitropyridine N-oxide than in parent 4-halopyridine N-oxide. According to quantum chemical ab initio HF/6-311G** calculations the amino tautomer of 4-chloro-2-methylamino-6-methyl-5-nitropyridine N-oxide is more stable than its imino form. Using B3LYP/6-311G*…
E-2-Benzylidenebenzocycloalkanones III. Studies on transmission of substituent effects on IR carbonyl stretching frequencies and 13C NMR chemical shi…
2004
Abstract Single substituent parameter and dual substituent parameter analysis was applied to study transmission of substituent effects on IR carbonyl stretching frequencies of E -2-(X-benzylidene)-1-indanones ( 3 ), -tetralones ( 4 ), and -benzosuberones ( 5 ). Similar analyses were performed for selected 13 C NMR chemical shifts of some E -2-(X-benzylidene)-1-indanones ( 3 ). For a better understanding of the results semiempirical and ab initio quantum chemical calculations were performed to determine the preferred geometry and to calculate the theoretical 13 C NMR chemical shifts of the selected compounds ( 3 ). The differences among the regression coefficients were discussed in terms of …
Using neural networks for (13)c NMR chemical shift prediction-comparison with traditional methods.
2002
Abstract Interpretation of 13 C chemical shifts is essential for structure elucidation of organic molecules by NMR. In this article, we present an improved neural network approach and compare its performance to that of commonly used approaches. Specifically, our recently proposed neural network ( J. Chem. Inf. Comput. Sci. 2000, 40, 1169–1176) is improved by introducing an extended hybrid numerical description of the carbon atom environment, resulting in a standard deviation (std. dev.) of 2.4 ppm for an independent test data set of ∼42,500 carbons. Thus, this neural network allows fast and accurate 13 C NMR chemical shift prediction without the necessity of access to molecule or fragment d…
Perthamides C-F, potent human antipsoriatic cyclopeptides
2011
Abstract Two new cyclopeptides, perthamides E and F were isolated from the polar extracts of the sponge Theonella swinhoei . The new structures, featuring an unprecedented β-amino acid unit (AHMOA), were determined by interpretation of NMR and MS data. The absolute configuration of the AHMOA residue was proposed on the basis of quantum chemical calculation of NMR chemical shifts. Perthamides were proved to inhibit TNF-α and IL-8 release in primary human keratinocytes cells and therefore could represent potentially leads for the treatment of psoriasis.
Low-energy symmetries of QCD and the structure of the nucleon
2015
Abstract We present some updated results regarding the scalar and electromagnetic structure of the nucleon obtained by the relativistic formulation of chiral effective field theory with baryons. We compare them with previous determinations available in the literature, and show their relevance for searches of physics beyond the standard model in the low energy frontier.
Accommodating three low-scale anomalies (g-2, Lamb shift, and Atomki) in the framed standard model
2019
The framed Standard Model (FSM) predicts a [Formula: see text] boson with mass around 20 MeV in the “hidden sector,” which mixes at tree level with the standard Higgs [Formula: see text] and hence acquires small couplings to quarks and leptons which can be calculated in the FSM apart from the mixing parameter [Formula: see text]. The exchange of this mixed state [Formula: see text] will contribute to [Formula: see text] and to the Lamb shift. By adjusting [Formula: see text] alone, it is found that the FSM can satisfy all present experimental bounds on the [Formula: see text] and Lamb shift anomalies for [Formula: see text] and [Formula: see text], and for the latter for both hydrogen and …
The Feasibility of a Text-Messaging Intervention Promoting Physical Activity in Shift Workers : A Process Evaluation
2023
Workplace health promotion programs (WHPPs) can improve shift workers’ physical activity. The purpose of this paper is to present the process evaluation of a text messaging health promotion intervention for mining shift workers during a 24-day shift cycle. Data collected from intervention participants with a logbook (n = 25) throughout the intervention, exit interviews (n = 7) and online surveys (n = 17) examined the WHPP using the RE-AIM (Reach, Efficacy, Adoption, Implementation and Maintenance) framework. The program reached 66% of workers across three departments, with 15% of participants dropping out. The program showed the potential to be adopted if the recruitment strategies are impr…
Measurement of vibrational line profiles inH2–rare-gas mixtures: Determination of the speed dependence of the line shift
1994
High-resolution inverse Raman experiments for ${\mathrm{H}}_{2}$ diluted in Ar have revealed unusual Q-line profile features at various concentrations which have been interpreted in terms of speed-changing collisions. A more general approach including both speed- and phase-changing collisions has led to an alternative interpretation of these features. In order to further analyze the role of these various collisional mechanisms, new experiments have been performed. Pure ${\mathrm{H}}_{2}$ and ${\mathrm{H}}_{2}$ perturbed by Ne, Ar, and Xe have been investigated at various temperatures between 295 and 800 K.
A comment on mortgage procylicality
2012
This paper comments on mortgage procyclicality. A framework for credit constraints along the lines of Kiyotaki and Moore (1997) is applied to illustrate a potential regime shift in the credit risk assessments of mortgagees. Depending on the relationship between house price growth and the alternative rate of return the weight given to collateral and debt-servicing ability may vary according to the house price cycle as mortgagees engage in search-for-yield. The regime shifts induced by increased global liquidity and expectations of continued housing appreciation might stimulate owner-occupation and LTV-ratios and induce mortgage procyclicality.