Search results for "Berg"
showing 10 items of 758 documents
Chemical composition of the essential oil of Cyanus adscendens (Bartl.) Soják and C. orbelicus (Velen.) Soják growing wild in Bulgaria, and PCA analy…
2022
Cyanus Mill. genus, belonging to the Asteraceae family, includes more than 50 taxa, mainly growing in Central and Southern Europe, North Africa, Asia Minor, and the Caucasus. Previous investigations on Cyanus taxa have shown that they are rich source of flavonoids and phenolic compounds but, differently from species of genus Centaurea, almost devoid of sesquiterpene lactones. In the present study, the chemical composition of the essential oils from aerial parts of Cyanus adscendens (CA) and C. orbelicus (CO), collected in Bulgaria, and not previously investigated, was evaluated by GC-MS. The main components of CA were α-bergamotene (31.3%), (Z,Z,Z)-9,12,15-octadecatrien-1-ol (14.5%) and cal…
Le ricerche di Aldo Visalberghi in campo didattico
2021
Il capitolo presenta gli interessi principali di studio e di ricerca di Aldo Visalberghi, preceduti da una breve parentesi biografica: delinea alcuni aspetti del pensiero di John Dewey quali fonti di ispirazione del pedagogista triestino; descrive la pedagogia esperienziale come sapere didattico-educativo da lui sostenuto; sintetizza il suo interesse per la valutazione nel processo educativo; descrive le variabili del condizionamento sociale nell’educazione scolastica da lui individuate; rileva la dimensione formativa della ricerca da lui valorizzata; evidenzia il valore sociale che Visalberghi attribuiva all’insegnamento e all’apprendimento; sottolinea il carattere ludiforme che egli asseg…
Influence of Bacteria <i>Pseudomonas fluorescens</i> on the Properties of Latvian Clay
2014
Wide varieties of bacteria are able to produce extracellular polymeric substances (EPS) which are mostly composed of polysaccharides. It is suggested that EPS substances can alter certain clay soil properties due to their ability to adhere to the surface of mineral particles. Most common used microorganisms by the researchers for this purpose are of either genus Bacillus or genus Pseudomonas. In this study growth of bacteria P. fluorescens AM PS11 culture in locally obtained clay is studied for the purpose of establishing their influence on rheological properties of clay. An attempt to evaluate it has been made using FT-IR and XRD. Change in plasticity of clay using Atterberg limits method …
Scaling theory of star polymers and general polymer networks in bulk and semi-infinite good solvents
1988
Theorie d'echelle utilisant l'equivalence entre la fonction generatrice du nombre total de configuration et la fonction de correlation a plusieurs spins du modele de Heisenberg classique a n composantes dans la limite n→0
A theoretical determination of the electronic spectrum of Methylenecyclopropene
1996
The vertical electronic spectrum of methylenecyclopropene, the prototype of the nonalternant hydrocarbons known as fulvenes, has been studied using multiconfigurational second-order perturbation theory. The calculations comprise three valence states and the 3s, 3p, and 3d members of the Rydberg series converging to the first π ionization limit. Vertical excitation energies to three valence states are found at 4.13, 6.12, and 6.82 eV. The second of them corresponds to an excitation from the highest occupied σ orbital to a π* orbital, while the other two are π → π* excitations. The third transition gives rise to the most intense feature in the electronic spectrum. The results are rationalized…
Theoretical Studies of the Electronic Spectra of Organic Molecules
1995
The complete active space (CAS) SCF method in conjunction with multiconfigurational second-order perturbation theory (CASPT2) has been used to study the electronic spectra of a large number of molecules. The wave functions and the transition properties are computed at the CASSCF level, while dynamic correlation contributions to the excitation energies are obtained through the perturbation treatment. The methods yield energies, which are accurate to at least 0.2 eV, except in a few cases, where the CASSCF reference function does not characterize the electronic state with sufficient accuracy. The applications comprise: the polyenes from ethene to octatetraene (cis- and trans-forms); a number …
Low-lying Rydberg states of HCl.
2008
Vertical excitation energies belonging to some different Rydberg series of hydrogen chloride have been determined with a coupled-cluster theoretical approach. These excitation energies have allowed us to calculate electric dipole transition intensities in HCl and allow additional assessment of the calculation approach presently used to provide an adequate description of the valence and Rydberg states of HCl. The molecular quantum defect orbital has been applied to the calculation of oscillator strengths. In particular, new insight is given on the assignment of states as the R1Pi, the 1Delta(4dpi and 5ppi), the 1Sigma+(4dpi), and the nddelta(1Pi, 1Phi) and 4f states.
A Theoretical Insight into the Photophysics of Acridine
2001
The electronic absorption and emission spectra of acridine have been studied by means of a multiconfigurational second-order perturbation method (CASSCF/CASPT2) and its multistate extension (MS-CASPT2). The low-lying valence singlet and triplet π → π* and n → π* excited states have been computed. The location of the lowest Rydberg state (3s) has been also estimated. By optimization of the geometries of the ground and low-lying excited states and the calculation of transition energies and properties, the obtained results lead to a complete analysis and assignment of the available experimental singlet−singlet and triplet−triplet absorption spectra and to the description of the basic features …
Species size affects hatching response to different temperature regimes in a rotifer cryptic species complex
2013
The strategy of decreasing size with increasing temperature known as Bergmann’s rule operates at geographic scale and in spite of extensive studies still presents a puzzle to researches. The aim of this work was to verify whether patterns of diapausing egg hatching of closely related species are consistent with the expectations from Bergmann’s rule. In a laboratory study of the cryptic species complex of the rotifer Brachionus plicatilis, the response to temperature (17.5, 22.5, and 25.0 °C) of diapausing eggs collected in a pond where the three tested species coexist was assessed by (1) the number of hatchlings emerging or (2) the time needed to hatch. Our results show that the response to…
A propósito de la localización de una pintura sobre tabla de ?La Virgen de la Leche?, del siglo XIV, atribuida a Bernabé de Módena, que perteneció al…
2020
The castle's Hermitage of Yecla (Region of Murcia) constituted during the 13th to 16th centuries the first parish of the population, hosting a triptych-shaped altarpiece presided over by a tempera painting on wood of Our Lady of Humility or "Virgo Lactans", dated around 1370 and attributed to the painter Barnaba da Modena, which was the titular image of the mentioned temple under the title of Our Lady of the Incarnation, until at the end of the 18th century it changed ownership for the Conception of Our Lady. The table at averages of the eight hundred was placed in an a loft, appropriating it at the beginning of the 20th century by the retired military Pascual Spuche y Lacy, who sold it aro…