PPP Calculations Research Articles

Precise Point Positioning and Differential Solutions by Online GNSS Calculation Tools and RTKLIB: A Comparative Study

The recent advances in GNSS positioning of the recent decades have been possible by the development of increasingly efficient software and online calculation tools. The differences between these online PPP calculation tools result in a different level of performance. Our study shows that for 24-hour or 6-hour observation time, the Canadian Spatial Reference System for PPP (CSRS-PPP), CenterPoint RTX Post-Processing (RTX), Magic/GNSS, Institut Geographique National-PPP (IGN-PPP) and RTKLIB tools have almost similar level of performance with International Terrestrial Reference Frame (ITRF) solutions considered as reference solution. Average deviations on the three components X, Y and Z for the different tools compared to ITRF solutions do not exceed 1 cm. However, the CSRS-PPP tool gives deviations of less than 5 mm. Calculations from the observations of 2 h and 1 h show that the RTX and CSRS-PPP tools keep deviations similar to those obtained with 24 h and 6 h, while RTKLIB and IGN-PPP give deviations exceeding 6 cm and sometimes failures of some calculations for IGN-PPP.

Calculation of Purchasing Power Parities for Pharmaceutical Products via EURIPID database

Abstract Background Purchasing power parities (PPPs) are indicators of price level differences for all goods and services across countries. Their calculation follows the ÉKS method (https://ec.europa.eu/eurostat/cache/metadata/en/prc_ppp_esms.htm). Prices of pharmaceuticals are collected by national statistical offices using different methods, from asking prices in pharmacies to retrieving scanner data. The sample is limited to 150 top-selling medicines, which are not available in all countries. Consequently, the PLIs (price level indices) and PPPs derived are sometimes based on only 50 pharmaceuticals. In a cooperation between Eurostat and EURIPID the PPP calculation was alternatively done with the EURIPID database for 28 countries. Methods The study compared the PLIs/PPPs derived from the E20-2 “Furniture and health” survey (aka CGS) with those from EURIPID for 2018-2020. The main challenge was to identify comparable products from the 224,448 products in EURIPID. For this we grouped those that shared the same 1) ATC, 2) active substance(s) & strength(s), 3) pack size group and 4) dosage form group (e.g., oromucosal) resulting in 157,186 distinctive products compared to 1,928 included in CGS. We used the Gross Retail price (GRP) as defined in the Eurostat PPP manual. Results The ranking of PPPs was similar in both approaches, with Switzerland and Iceland in the lead and Poland and Hungary in the end. Only for some countries, e.g. the Netherlands deviations were identified. The Pearson correlation between the 2020 PLI for the Euripid subsample using the asterisk method with all products marked as representative and the CGS results was 0,946. Conclusions Results from EURIPID show the same trend as the CGS. It is possible to replace the national data collection by a central source. This would reduce the data collection burden on the statistical offices and allows a closer monitoring of the evolution of pharmaceutical prices (bi-annual PPP publication instead of current 3-year interval) Key messages • To monitor affordability of medicines for all citizens it is important to compare prices on a regular basis with a simple tool as e.g. some products prices differed by 1000-times across countries. • The EURIPID database (www.euripid.eu) allows detailed analysis of pharmaceutical prices in Europe and is available for free to non-commerical researchers.

Temporal comparisons of prices, expenditure and growth in India: a state-wise analysis

Purpose – The contribution of this study is both methodological and empirical. It provides a method of estimating preference consistent true cost of living indices and demonstrates the use of unit values (food items), adjusted for quality and demographic effects, as prices. Using NSS data, changes in living standards (measured by per capita real expenditure) in India are examined between 1999/2000 and 2009/2010. The paper aims to discuss these issues. Design/methodology/approach – From the adjusted unit values, “exact” price indices are computed using QAIDS-based preference consistent methods that allow between-item substitution effects and variation across states. Findings – A comparison of the nominal and price deflated real expenditures under alternative temporal price scenario during 1999/2000-2009/2010 shows that the states largely preserve their ranks over the periods, in spite of differential temporal price movement. However, comparison of the nominal and price-deflated real expenditure growth reveals that the rankings are sensitive to the price deflator used. Practical implications – The results question the wisdom of the treatment of large countries with heterogeneous preferences, e.g. India, as single entities in PPP calculations as in the ICP project. Hence, the results have methodological and empirical implications that extend beyond India. Originality/value – The study provides evidence on the issue of spatial difference in the temporal movement in prices, where no such evidence exists, and contains the first evidence on living standards in India in the post global financial crisis era. Also, this is the first attempt to base calculation of temporal movement in prices, as measured by the “exact” price indices, on the adjusted unit values of food items.

Electronic structures of low-lying Bu excited states in trans-oligoenes: Pariser-Parr-Pople and ab initio calculations

Two lowest-lying excited singlets with B(u) symmetry of all-trans-oligoenes, the well-known ionic 1(1)B(u)(+) state as well as the "hidden" ionic-covalent-mixed 1(1)B(u)(-) state, are calculated within both the Pariser-Parr-Pople (PPP) model at full configuration interaction (FCI) level and ab initio methods. The vertical excitation energies as well as wavefunctions from PPP-FCI calculations are found to be in good agreement with those from high-level multi-reference methods, such as multi-reference complete active space self-consistent field (CASSCF) with second order perturbative corrections (CASPT2), multi-reference Møller-Plesset perturbation theory (MRMP), and complete active space valence bond theory (CASVB). The oscillator strengths from PPP calculation are in good agreement with spectroscopy experiments. The relatively small oscillator strength of 1(1)B(u)(-) is due to the approximate electron-hole symmetry of this state. In addition, the bond lengths in both states are found to show remarkable relativity with the bond orders calculated with ground state geometries, which suggests a possible strategy for initial guess in geometry optimization of excited states.

Opacity and radiative power losses calculations

In this contribution we present results on opacity and radiative power losses in laser-produced plasmas. We focus our attention on the inner shell transition array 1 s–2 p in an aluminum plasma. At high densities, electron, Doppler and ion Stark broadening play a role in line merging. This is why the PPP line-shape code developed at Université de Provence was adapted to calculate opacity and radiative power losses in Al and Ge ions. Atomic physics data required in PPP calculations is provided by an MCDF code. Comparison with experiments is discussed.

NMR and MO Studies on the Molecular Structure of a Fluoranthene-Benzene Complex

Fluoranthene (FA) forms a 1:1 van der Waals complex with benzene in cyclohexane. The 1H NMR spectrum of this complex shows that the FA moiety in the complex state has five kinds of hydrogen atoms and that the 1H NMR peaks assigned to the protons attached to the naphthalene skeleton are largely shifted to higher magnetic field on complex formation with benzene. These observations indicate that the complex takes the structure of C S symmetry, in which the benzene molecule mainly interacts with the π electronic system localized on the naphthalene moiety of FA. The present ab initio calculations reproduce well the 1H NMR spectral shifts mentioned above and the experimentally predicted C S structure of the complex. According to the PPP calculations for the electronic absorption spectral changes on the complex formation, the FA-benzene complex is considered to take a sandwich type structure.

Effect of peripheral substitution on the electronic absorption and fluorescence spectra of metal-free and zinc phthalocyanines.

The effect of substituents on the position and intensity of the electronic absorption and fluorescence spectra of phthalocyanines (Pcs) was examined for 35 Pc compounds. When electron-releasing groups are bound to four alpha-benzo positions of the Pc skeleton, the B and Q bands shift to longer wavelength. Relative to this shift, the effect of introducing the same electron-releasing groups at the other four alpha positions amounts to about 1.6-2.0. Although the effect is not always clearly seen, introduction of electron-releasing groups in the beta-benzo positions of the Pc skeleton generally shifts the Q band to shorter wavelength. The effect of electron-withdrawing groups is exactly the opposite with respect to the alpha and beta positions. These effects can be reasonably explained by considering the magnitude of the atomic orbital coefficients of the carbon atoms derived from molecular orbital (MO) calculations. In addition, the following intriguing phenomena were observed in the experiments, although not all were explained theoretically: 1) the splitting of the Q band of metal-free Pcs decreases with increasing wavelength of the Q band, 2) the ring currents of Pcs with Q bands at longer wavelength are generally smaller, and 3) the absorption coefficients of the Q band of Pc compounds with 16-electron-releasing substituents are larger than those of the corresponding tetra- and octasubstituted Pcs by several tens of percent. 4) Our PPP calculations suggested that the absorption coefficient of the Q band of Pcs with more strongly electron releasing substituents is larger. 5) The second HOMO of the Pcs with the Q band at longer wavelength has b(1u) symmetry, as opposed to the a(2u) symmetry of normal Pcs. 6) Pcs showing S1 emission maxima at wavelengths longer than about 740 nm generally have quantum yields of less than 0.1.

Induced Circular Dichroism and Magnetic Circular Dichroism Spectra of Maleimide and Related Molecules

AbstractThe induced circular dichroism (ICD) spectra of the inclusion complexes of maleimide, phthalimide, and naphthalene‐2,3‐dicarboximide with β‐ or γ‐cyclodextrin (CDx) have been measured. The structure of the CDx inclusion complexes are interpreted by the signs and shapes of ICD spectra compared with the results of PPP calculations. In maleimide and naphthalene‐2,3‐dicarboximide, the ICD spectra of the β‐CDx inclusion complex are very similar to those of the γ‐CDx inclusion complex in spite of the differences in dimensions between the cavity of β‐CDx and that of γ‐CDx. In phthalimide, the ICD spectra of the β‐CDx inclusion complex are very different from those of the γ‐CDx inclusion complex. The split‐type ICD bands at 220–235 nm show that the dimer of phthalimide is formed in the presence of β‐CDx.

MS-Windows Application for a PPP Calculation using the Novel Two-Center Electron Repulsion Integral

The application of Windows 95/98/NT for PPP MO (Pariser-Parr-Pople molecular orbital) calculation was developed by using the Inprise C++ builder. The novel two-center electron repulsion integral (new-γ), the concept of spectrochemical softness parameter krs for PPP calculation, was introduced in this application. The user can perform quickly the modeling of π-conjugated compounds on a PC monitor and select many suitable parameters (for example, ionization potentials, resonance integrals etc.) for the PPP calculation. The SCF calculation was momentarily performed and oscillator strength and LCAO coefficients of HOMO, LUMO or others were displayed. The calculations gave satisfactory results for the prediction of the electronic absorption spectra of polycyclic aromatic hydrocarbons(PAHs), symmetric cyanins and so on.

Electronic absorption spectra of benzoquinone and its hydroxy substituents and effect of solvents on their spectra

The electronic absorption spectra of 1,4-benzoquinone (BQ) and its 2,5-dihydroxy and tetrahydroxy derivatives have been studied in detail. The interpretation of the electronic bands is made on the basis of PPP and CNDO calculations. It is found that the π→π* transitions are well predicted by the PPP method. The predictions of the CNDO method are however superior both in their accuracy as well as ability to predict the n→π* transitions. The effect of solvents on the electronic absorption bands have also been investigated in detail. Linear correlations are found between the solvent’s dielectric constant and wavelength of the absorption bands. The solvent shifts are explained on the basis of the polarities of the solute and solvent molecules as well as due to hydrogen bonding.

PPP Calculations for Electronic Spectra of Cyanine Dyes (Part 2).

PPP Calculations for Electronic Spectra of Cyanine Dyes (Part 2).

An Experimental and Theoretical Study of the Photophysical Properties and the Dipole Moments of Methoxynitronaphthalenes

Isomeric methoxynitronaphthalenes (MNN, 14 possible isomers, cf. Scheme 1) were studied theoretically and experimentally. PPP calculations were carried out for all possible isomers and the results were compared with the experimental electronic absorption, fluorescence, and phosphorence spectra of selected isomers. Also the phosphorescence lifetimes were determined. Theoretical ground-state dipole moments of MNN were obtained as a combination of the π-component (PPP method) and the [sgrave]-component (a vector sum of à-bond and group moments). The experimental groundstate dipole moments were measured for a series of MNN (on a dipole meter) and compared with the theoretical values. The effect of solvent polarity upon the electronic absorption and fluorescence spectra of selected MNN was studied and the solvatochromic method using the Bakhshiev and Kawski-Chamma-Viallet equations and the ground-state dipole moments was employed to obtain the experimental first excited singlet-state dipole moments.

シアニン色素の電子スペクトルのPPP計算

N, N'-二置換体 (2, 4), N, N.N', N'=四置換体 (1, 5) を含む一連のcyanine色素 (3) の電子スペクトルにおける吸収極大を, 新概念 (new-γ) の二中心電子反発積分を考慮した式, γrs=e2/ (Rrs+kαrs) を用いたPariser Parr-Pople (PPP) 分子軌道法により計算した。new-γにおけるspectrochemical softness (SCS) パラメータんは, π共役系における二重結合数πを用いて, k=0.33π+0.48とする式により決定した。この式は, 直線状polyaceneのp-吸収帯計算においてんの値をpolyaceneの6員環の数Zを用いた式, k-〇.33Z+0.48と一致する。マリケンの超共役に関する理論に基づき, メチル基は擬似的に2っのπ電子を共役系に供給するとした。炭素原子の第ニイオン化ポテンシャルをメチル基の価電子イオン化ポテンシャル (Ir) として用いた。計算したシアニン色素の吸収極大波長は, 実測値とよく一致した。

Factorization of interaction graphs withn-fold symmetry: Some applications in PPP calculation and molecular vibrational analysis

Factorization of interaction graphs withn-fold symmetry: Some applications in PPP calculation and molecular vibrational analysis

Factorization of interaction graphs with n‐fold symmetry: Some applications in PPP calculation and molecular vibrational analysis

Factorization of interaction graphs with n‐fold symmetry: Some applications in PPP calculation and molecular vibrational analysis

UV–VIS–Near-IR, MO and EPR studies of five redox stages of an octaethyltetraoxa[26]porphyrin

The radical cation (3˙+), the radical anion (3˙–) and the, diamon (32–) of 2,3,9,10,16,17,23,24-octaethyltetraoxa[26]porphyrin were generated from the neutral compound (3) and the dication (32+). The electronic spectra of these five redox stages resemble those in the tetraoxaporphyrin series, 12+, 1˙+, 1,1˙– and 12–, but are shifted to lower energies by 0.7–1.0 eV. Thus, the Soret and Q bands of the four charged species, 32 +, 3˙+, 3˙– and 32–, lie at 450–600 and 700–1300 nm, respectively. The spectrum of the neutral 3 is characteristic of 4nπ-systems. The absorption bands were assigned to electronic transitions with the use of PPP calculations. The diions 32 + and 32– are predicted to preserve the symmetry D4h of the π-system with cyclic delocalization along the 28-membered perimeter, whereas in the neutral 3 the symmetry is lowered to D2h with localization of the double bonds. The four oxygen atoms in 32+ should bear one positive charge which is only slightly decreased on consecutive reductions, so that the additional negative charges are taken up almost exclusively by the perimeter. Proton-coupling constants were determined for the radical cation 3˙+ and the radical anion 3˙– by EPR spectroscopy. Within the limits of experimental resolution, they are the same for both radical ions and consistent with an effective D4h symmetry. The large inherent width of the EPR lines–and their reluctance to saturation–point to a degenerate or nearly degenerate ground state of 3˙+ and 3˙– undergoing a dynamic Jahn–Teller effect.

UV-VIS spectra of some 3-arylazopropenoic acid esters

The π-electronic transitions of 2-aryl- and 2-amino-3-arylazopropenoic acid esters were interpreted in terms of localisation on molecular fragments and charge transfer between them. The localisation is characterised by atomic and the respective fragmental localisation numbers LA obtained by a transition density matrix formalism within a standard PPP calculation. A band analysis of the UV spectra based on a normal logarithmic distribution function is presented.

Electronic transitions of salicylaldehydeethylenediimine and its Cu(II) complexes

AbstractElectronic absorption spectra of Salicylaldehydeethylenediimine (salen) and its Cu(II) complexes have been measured in various media at various temperatures. It is found that salen takes an enol‐imine‐type structure in cyclohexane and exists as an equilibrium mixture of enol‐imine and keto‐amine type species in alcoholic media. The polarization spectrum of salen‐Cu(II) measured in the stretched PVA film shows that 282, ∼ 290, ∼ 250, and 230.4 nm bands are polarized along the longer‐molecular‐axis, and 354, 273.0, 242.4 and ∼ 220 nm bands along the shorter‐molecular‐axis. The 242.4 and ∼ 250 nm bands can be assigned to intramolecular charge transfer (CT) transitions between the metal ion and ligand and between the two π‐electronic systems of the ligand, respectively. The complex of salen‐Cu(II) forms a dimer in EPA (ether: isopentane: ethanol = 5:5:2 in volume) at low temperatures. The first two bands of the monomer at 380 and 362 nm are blue‐shifted by the dimer formation, and appear at 370 and 351 nm, respectively, and the 278 nm monomer band splits into two bands at 275 and 267 nm. These spectral changes on the dimer formation are well reproduced by an extended PPP calculation.

Structure-color correlations of penta- and heptamethines: Syntheses with nitriles XCIV

The synthesis of asymmetric cyanine dyes (penta- and heptamethines), prepared by coupling Fischer's base with indandione, benzo[b]thiophene and pyrazole derivatives via a C-1 unit, is described. Three different synthetic strategies for substituted polymethines are presented. Dye characteristics are given and the correlation between the chemical structures and the dye properties are discussed by means of semiempirical PPP calculations.

4,4′-Binaphthylidendione - Farbe und Struktur / 4,4′-Binaphthylidene-1,1′-diones — Colour and Structure

Synthesis and properties of various 4,4′-binaphthylidene-1,1′-diones are described. The UV spectra of the deep red to purple diones may be calculated on the base of substituent increments. The experimental values of the analyzed substituents can be reproduced using PPP calculations with satisfying accuracy, which makes it possible to predict also absorption maxima of hitherto unknown 4,4′-binaphthylidene-1,1′-diones