Search results for "shift"

NMR Spectroscopic and quantum chemical characterization of the (E)- and (Z)- isomers of the penta-1,3-dienyl-2-cation

2003

Dilute solutions of the (E )− and (Z )− isomers of pent-1,3-dienyl-2-cations (1) were obtained from reaction of 4-chloro-1,2-pentadiene (2) with SbF5 in SO2ClF/SO2F2 at −135 °C using high-vacuum co-condensation techniques. The experimental NMR spectra of the mixture of the two isomers were compared with quantum chemical 13C NMR chemical shift calculations at HF-SCF, MP2, CCSD and CCSD(T) levels using MP2/tzp geometries. Quantum chemical shift calculations were performed with a tzp basis (9s5p1d/5s3p1d) for carbon and a dz basis (4s/2s) for hydrogen using gauge-including atomic orbitals (GIAOs). The HF-SCF calculations deviate significantly for the positively charged carbon atoms of the ally…

Estimating the substitutability between private and public consumption: the case of Spain, 1960–2003

2005

This paper examines the relationship between private and public consumption using Spanish data over the period 1960–2003, using a two-good permanent-income model. We extend previous analysis addressing the question of whether this relationship is stable over time, or exhibits a structural break allowing the instability to occur at an unknown point in time. Our empirical results indicated the existence of a long-run relationship between private and public consumption. We also detect a structural change of regime shift in the cointegration regression around the time of 1973–74. Finally, the estimated intratemporal and intertemporal elasticities of substitution between the two types of expendi…

Tuning four-wave mixing through temperature in ethanol-filled photonic crystal fiber

2016

In this paper, continuous tuning of four-wave mixing bands in an ethanol-filled photonic crystal fiber is investigated. A wide tuning range of the parametric bands, from 745 nm to 920 nm (signal) and from 1260 nm to 1710 nm (idler), is achieved through the thermo-optic effect. This corresponds to a frequency tuning range higher than 2000 cm−1; such wide range can be particularly useful in applications that require broadband wavelength conversion, e.g., CARS microscopy. Numerical calculations are in good agreement with experimental measurements.

Synthesis of 8,9-dihydrodipyrazolo[3,4-b:4′,3′-f][1,5]diazocin-10(1H)-one. A new ring system

1995

8,9-Dihydrodipyrazolo[3,4-b:4′,3′-f][1,5]diazocin-10(1H)-ones 7 were prepared by cyclization of 1-ethyl-N,3-dimethyl-4-acetamido-N-(1-R1-3-R2-1H-pyrazol-5-yl)-1H-pyrazole-5-carboxamides 6 by a Bischler-Napieralski cyclization. A complete assignment of the chemical shifts to the carbon atoms of compound 7 was performed by different nmr experiments, such as DEPT and XHDEPT for onebond CH correlations and COLOC experiments for long-range C-H correlations.

<em>El dibujado</em>: volver a la pared

2021

The exhibition El dibujado by Paco Roca (IVAM, 2019) is an exploration of the paradigm shift brought forth by the abandonment of paper and reproducibility as a space for the dissemination of the comic strip. The exhibition hall of a museum (the Instituto Valenciano de Arte Moderno) becomes a space for formal and ephemeral experimentation at different levels, from the purely creative to the pondering about the unexplored possibilities of the language of the comic book. With this exhibition cartoonist Paco Roca poses a challenge to a spectator who is called to leave his/her role as a visitor and become the reader of an experience in which s/he becomes a part of the work’s own narrative. The a…

Familial hypobetalipoproteinemia: Analysis by next generation sequencing and identification of a novel frameshift mutation in the apoB gene

2017

Pressure Shift and Gravitational Red Shift of Balmer Lines in White Dwarfs. Rediscussion

2015

The Stark-induced shift and asymmetry, the so-called pressure shift (PS) of $H_\alpha$ and $H_\beta$ Balmer lines in spectra of DA white dwarfs (WDs), as masking effects in measurements of the gravitational red shift in WDs, have been examined in detail. The results are compared with our earlier ones from before a quarter of a century (Grabowski et al. 1987, hereafter ApJ'87; Madej and Grabowski 1990). In these earlier papers, as a dominant constituent of the Balmer-line-profiles, the standard, symmetrical Stark line profiles, shifted as the whole by PS-effect, were applied to all spectrally active layers of the WD atmosphere. At present, in each of the WD layers, the Stark-line-profiles (e…

GW170817: Implications for the Stochastic Gravitational-Wave Background from Compact Binary Coalescences

2018

The LIGO Scientific and Virgo Collaborations have announced the first detection of gravitational waves from the coalescence of two neutron stars. The merger rate of binary neutron stars estimated from this event suggests that distant, unresolvable binary neutron stars create a significant astrophysical stochastic gravitational-wave background. The binary neutron star background will add to the background from binary black holes, increasing the amplitude of the total astrophysical background relative to previous expectations. In the Advanced LIGO-Virgo frequency band most sensitive to stochastic backgrounds (near 25 Hz), we predict a total astrophysical background with amplitude $\Omega_{\rm…

Efectos de la crisis económica de 2008 sobre el empleo en las cooperativas andaluzas: un estudio del impacto provincial mediante el análisis shift-sh…

2018

Durante la reciente crisis económica, las cooperativas instaladas en la comunidad autónoma de Andalucía han demostrado ser una opción estratégica de desarrollo territorial con mayor estabilidad en el empleo frente a otras formas jurídicas empresariales. Este comportamiento es una consecuencia de su capacidad para
 actuar como elemento dinamizador y de adaptación a las singularidades de los territorios sobre los que actúa. Sin embargo, del análisis a nivel provincial efectuado en esta investigación se constata un comportamiento diferenciado, debido en gran medida a la existencia de diferencias socioeconómicas entre ellas.
 En este trabajo se propone la utilización de la metodología…

Star-Shaped Compounds Having 1,3,5-Triazine Cores

2003

The 1,3,5-triazine derivatives 1−4 having styryl or higher oligo(phenylenevinylene) chains in the 2-, 4-, and 6-positions represent star-shaped push-pull compounds. Alkoxy or dimethylamino groups on the peripheral benzene rings, which act as electron donors, and the central 1,3,5-triazine ring, which acts as an electron acceptor, cause intramolecular charge transfer (ICT) to occur in the absorption S0⇄S1. Protonation of the 1,3,5-triazine core enhances the effect, as demonstrated by a bathochromic shift; a secondary protonation on the dimethylamino groups, however, leads to the breakdown of the ICT. Thus, the yellow compound 1d first becomes violet and then colorless upon the addition of tr…