Two effects relevant for the study of astrophysical reaction rates: gamma transitions in capture reactions and Coulomb suppression of the stellar enhancement

Nucleosynthesis processes involve reactions on several thousand nuclei, both close to and far off stability. The preparation of reaction rates to be used in astrophysical investigations requires experimental and theoretical input. In this context, two interesting aspects are discussed: (i) the relevant gamma transition energies in astrophysical capture reactions, and (ii) the newly discovered Coulomb suppression of the stellar enhancement factor. The latter makes a number of reactions with negative Q value more favorable for experimental investigation than their inverse reactions, contrary to common belief.Comment: 5 pages, 5 figures, to appear in the proceedings of CGS 13 (Int. Conf. Capture Gamma Ray Spectroscopy and Related Topics

Symmetries at and Near Critical Points of Quantum Phase Transitions in Nuclei

We examine several types of symmetries which are relevant to quantum phase transitions in nuclei. These include: critical-point, quasidynamical, and partial dynamical symmetries.Comment: 5 pages, 4 figures, Proc. 13th Int. Conf. on "Capture Gamma-Ray Spectroscopy and Related Topics", August 25-29, 2008, Cologne, German

El derecho internacional de los negocios y los contratos a comisión en el sector del petróleo: una laguna sombría

[EN] The energy sector plays a fundamental role in all countries, especially oil. In the context of commission-based contracts in this part of the energy sector, it is certainly complex and filled with nuances. Although it may be typically considered to be a highly regulated and surveilled sector, the reality reveals many dichotomies. This is even more exacerbated in a market of intermediaries, where individuals external to any company or state take part in trading operations that fuel an entire nation. Despite the existence of supranational entities responsible for ensuring proper functioning, they exert almost no influence over the external market. Consequently, participants of this market must adhere to guidelines and recommendation build by external entities, but above all their own free will. Although these norms are mere guidelines, they have been implemented in such a way that they are even accepted as if they were de iure laws. The lack of fixed legislation has been a challenge to overcome by the whole sector; however, within the anarchic under which this sector operates, still a harmony can be found that balances and counterbalances all the parties involved.[ES] El sector energético juega un papel fundamental en todos los países especialmente el petróleo. En el contexto de los contratos a comisión en este sector de la energía, es indudablemente complejo y lleno de matices. A pesar de ser comúnmente considerado como un sector muy regulado y vigilado, la realidad es que hay muchos claroscuros en este sector. Aún más en un mercado de comisionistas, donde alguien ajeno a toda empresa o estado toma parte en operaciones de negociación de a la fuerza que alimenta a toda una nación. Aunque haya entidades supranacionales a cargo de la supervisión de su correcto funcionamiento, estas ejercen una casi nula influencia sobre el mercado exterior. Siendo de este modo que los partícipes de este mercado tengan que regirse por guías, recomendaciones de entidades externas, pero ante todo la autonomía de su voluntad. A pesar de que estas normas son unas meras guías, estas han llegado a implantarse de tal manera que incluso llegan a ser aceptadas como si estas fuesen una ley de iure. La falta de una legislación fija ha sido un reto para superar, sin embargo, dentro de la anarquía bajo la que se sitúa este sector, se puede encontrar una armonía que pone en equilibrio y contrapeso a todos los actores partícipes en esta.[RU] Енергийният сектор играе важна роля във всички страни, особено в сферата на петрола контекста на договорите за комисионните в този енергиен сектор, той несъмнено е сложен и изпълнен с нюанси. Въпреки че обикновено се смята за добре регулиран и контролиран сектор, истината е че има много противоречия в него. Това е още по-ясно изразено в един пазар на посредници, където външни лица за някоя компания или държава участват в търговски операции, които хранят цяла една нация. Въпреки че съществуват наднационални институции, които следят за коректното функциониране, те почти не оказват никакво влияние върху външния пазар. По този начин участниците в този пазар трябва да се ръководят от насоките и препоръките на външни субекти, но преди всичко от собствената си воля. Въпреки че тези норми са само насоки, те се прилагат до такава степен, че дори са възприемат да се прилагат като де юре закони. Липсата на установено законодателство представлява предизвикателство за целия сектор, въпреки че в анархията, в която оперира този сектор, може да се намери хармония която балансира и уравновесява всички участващи страни

Quantum phase transitions in rotating nuclei

We extend the classical Landau theory for rotating nuclei and show that the backbending in 162Yb, that comes about as a result of the two-quasiparticle alignment, is identified with the second order phase transition. We found that the backbending in 156Dy, caused by the instability of $\gamma$-vibrations in the rotating frame, corresponds to the first order phase transition.Comment: 4 pages, 2 figure

Extraction-Spectrophotometric Studies on the Ion-Pairing Between Some 2,3,5-Substituted Monotetrazolium Cations and Anions Deriving from 4-(2-Thiazolylazo)resorcinol or 4-(2-Pyridylazo)resorcinol

The ion-pairing between some 2,3,5-substituted monotetrazolium cations (T+) and anions deriving from 4-(2-pyridylazo)resorcinol (PAR) or 4-(2-thiazolylazo)resorcinol (TAR) was studied by water-chloroform extraction and spectrophotometry. The following tetrazolium salts (TS) were used as a source of T+: i) 2,3,5-triphenyl-2H-tetrazolium chloride (TTC); ii) 3-(4,5-dimethyl-2-thiazol)-2,5-diphenyl-2H-tetrazolium bromide (MTT); iii) 3-(2-naphtyl)-2,5-diphenyl-2H-tetrazolium chloride (Tetrazolium violet, TV); and iv) 2-(4-iodophenyl)-3-(4-nitrophenyl)-5-phenyl-2H-tetrazolium chloride (INT). The spectral characteristics of the extracted species were established at different pH and TS concentration. The composition and stability of the ion-pairs were determined at pH 9, where the extraction of neutral PAR (H2PAR) and TAR (H2TAR) species was negligible. The results showed that the ion-pairs can be expressed with the following formulae (T+)(HTAR–) (where T+ = TT+, MTT+, TV+ or INT+), (T+)(HPAR–) (where T+ = TT+, MTT+ or TV+) and [(INT+)(HPAR–)]2. Relationships involving the molecular masses of the ion-pairs (MIP) or T+ (MT+) and the values of the constants of association (b) or conditional molar absorptivities (e’) were examined, namely Log b = f(Log MIP) and e’ = f(Log MT+). Some practical aspects concerning the investigation of metal complexes with TS-PAR/TS-TAR were discussed

LIQUID-LIQUID EXTRACTION-SPECTROPHOTOMETRIC DETERMINATION OF MOLYBDENUM USING o-HYDROXYTHIOPHENOLS

27 liquid-liquid extraction-chromogenic systems containing Mo(VI), o-hydroxythiophenol derivative {HTPDs: 2-hydroxy-5-chlorothiophenol (HCTP), 2-hydroxy-5-bromothiophenol (HBTP) or 2-hydroxy-5-iodothiophenol (HITP)} and aromatic amine (AA) were studied. Aniline (An), N-methylaniline (mAn), N,N-dimethylaniline (dAn), o-toluidine (o-Tol), m-toluidine (m-Tol), p-toluidine (p-Tol), 3,4-xylidine (o-Xyl), 2,4-xylidine (m-Xyl), and 2,5-xylidine (p-Xyl) were the examined AAs. Optimization experiments for molybdenum extraction-spectrophotometric determination were performed and the following parameters were found for each of the systems: organic solvent (opt), pH (opt), CHTPD (opt), CAA (opt), shaking time (opt), l (max) and e (max). Under the optimum conditions, the molar ratio of the reacting Mo(V), HTPD and AA was 1:2:2 and the degrees of Mo extraction were R³98.4%. Linear relationships involving the spectral characteristics of the extracted complexes (lmax or emax) and some fundamental properties of the halogen substituent in the HTPD were discussed. The effect of foreign ions was examined and two sensitive, selective and precise procedures for extraction-spectrophotometric determination of molybdenum were proposed. The relative standard deviations for Mo content of (3-5)´10–4 mass % were 4% (HCTP-An procedure) and 3% (HBTP-An procedure)

A shell-model study of the light Cd isotopes

In an attempt to describe the excitation spectra and transitions strengths of light even-even Cd-isotopes (A = 98 - 108), large-scale shell-model calculations in the proton (2p(1/2), 1g(9/2)) and the neutron (2d(5/2), 1g(7/2), 2d(3/2), 3s(1/2), 1h(11/2)) model space were performed. Preliminary results are presented and discussed

Изкуствен интелект и графичен дизайн

Връзката между изкуствения интелект (ИИ) и графичния дизайн е тясна и все по-значима в света на технологиите и креативността. Графичният дизайн включва използването на различни елементи, като изображения, текстове и цветове, за да се създаде визуална комуникация. Този процес често пъти е бавен и трудоемък. Изкуственият интелект може да бъде полезен за автоматизиране на тези процеси и да подобри ефективността на дизайнерската работа. В съвременната епоха е мощно оръжие, за създаване на нови графични елементи, подобряване на качеството на дизайните и анализ на потребителското поведение. В бъдеще, се очаква тези възможности да се развиват и да се появят нови начини за използване на изкуствения интелект в графичния дизайн, но не трябва да се забравят опасностите, които крие този необятен нов инструмент.The connection between artificial intelligence (AI) and graphic design is close and increasingly significant in the world of technology and creativity. Graphic design involves the use of various elements, such as images, text, and color, to create visual communication. This process is often slow and laborious. Artificial intelligence can be useful to automate these processes and improve the efficiency of design work. Artificial intelligence in the modern era is a powerful weapon for creating new graphic elements, improving the quality of designs and analyzing user behavior. In the future, it is expected that these capabilities will develop and new ways to use artificial intelligence in graphic design will appear, but one should not forget the dangers that this spanless new tool hides

Доценту Йордану Еленскому 80 лет

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