Effects Of The Coulomb Correlation On The Calculated Results For Atoms With And Without Spin Polarization

In this paper we present the results of some atomic calculations as affected by the Coulomb correlation. We deal with atoms and ions with and without spin polarization. Thus we are able to compare calculated energy eigenvalues and hyperfine fields of contact with the experimental ionization energies and fields. Our approximation for the mass operator (exchange plus correlation) can thus be compared with the approximations proposed by Slater, Gaspar, Kohn and Sham, and Liberman. A broad evaluation of the results implies that our approximation for exchange and correlation is correct. Furthermore, when neglecting the correlation effects, we noticed that the results become poorer. Thus, this paper favors a single-particle description of many-body systems based on an effective-wave equation with the mass operator instead of the simpler exchange operator of the Hartree-Fock theory. © 1971 The American Physical Society.341224123

Microscopic Description Of The Phase Separation Process In Al Xgayin1-x-yn Quaternary Alloys

Ab initio total energy electronic structure calculations are combined with Monte Carlo simulations to study the thermodynamic properties of Al xGayIn1-x-yN quaternary alloys. We provide a microscopic description of the phase separation process by analyzing the thermodynamic behavior of the different atoms with respect to the temperature and cation contents. We obtained, at growth temperatures, the range of compositions for the stable and unstable phases. The presence of Al in InGaN is proven to "catalyze" the phase separation process for the formation of the In-rich phase. Based on our results, we propose that the ultraviolet emission currently seen in samples containing AlInGaN quaternaries arises from the matrix of a random alloy, in which composition fluctuations toward InGaN- and AlGaN-like alloys formation may be present, and that a coexisting emission in the green-blue region results from the In-rich segregated clusters.707732021-073202-4Lemos, V., Silveira, E., Leite, J.R., Tabata, A., Trentin, R., Scolfaro, L.M.R., Frey, T., Lischka, K., (2000) Phys. Rev. Lett., 84, p. 3666. , and references thereinKung, P., Razegui, M., (2000) Opto-Electron. Rev., 8, p. 201Kneissl, M., Treat, D.W., Teepe, M., Miyashita, N., Johnson, N.M., (2003) Appl. Phys. Lett., 82, p. 2386Adivarahan, V., Chitnis, A., Zhang, J.P., Shatalov, M., Yang, J.W., Simin, G., Khan, M.A., Shur, M.S., (2001) Appl. Phys. Lett., 79, p. 4240Yasan, A., McClintock, R., Mayes, K., Darvish, S.R., Zhang, H., Kung, P., Razeghi, M., Han, J.Y., (2002) Appl. Phys. Lett., 81, p. 2151Nagahama, S., Yanamoto, T., Sano, M., Mukai, T., (2001) Jpn. J. Appl. Phys., Part 2, 40, pp. L778Teles, L.K., Furthmüller, J., Scolfaro, L.M.R., Leite, J.R., Bechstedt, F., (2000) Phys. Rev. B, 62, p. 2475Teles, L.K., Scolfaro, L.M.R., Leite, J.R., Furthmüller, J., Bechstedt, F., (2002) J. Appl. Phys., 92, p. 7109Tamulaitis, G., Kazlauskas, K., Jursenas, S., Zukauskas, A., Khan, M.A., Yang, J.W., Zhang, J., Gaska, R., (2000) Appl. Phys. Lett., 77, p. 2136Hirayama, H., Kinoshita, A., Yamabi, T., Enomoto, Y., Hirata, A., Araki, T., Nanishi, Y., Aoyagi, Y., (2002) Appl. Phys. Lett., 80, p. 207Chen, C.H., Chen, Y.F., Lan, Z.H., Chen, L.C., Chen, K.H., Jiang, H.X., Lin, J.Y., (2004) Appl. Phys. Lett., 84, p. 1480Feng, S.W., Cheng, Y.C., Chung, Y.Y., Yang, C.C., Ma, K.J., Yan, C.C., Hsu, C., Jiang, H.X., (2003) Appl. Phys. Lett., 82, p. 1377Yamaguchi, S., Kariya, M., Nitta, S., Kato, H., Takeuchi, T., Wetzel, C., Amano, H., Akasaki, I., (1998) J. Cryst. Growth, 195, p. 309Takayama, T., Yuri, M., Itoh, K., Harris Jr., J.S., (2001) J. Appl. Phys., 90, p. 2358Matsuoka, T., (1998) MRS Internet J. Nitride Semicond. Res., 3, p. 54Marques, M., Teles, L.K., Ferreira, L.G., Scolfaro, L.M.R., Leite, J.R., unpublishedKresse, G., Furthmüller, J., (1996) Comput. Mater. Sci., 6, p. 15Marques, M., Teles, L.K., Scolfaro, L.M.R., Leite, J.R., Furthmüller, J., Bechstedt, F., (2003) Appl. Phys. Lett., 83, p. 890Ferreira, L.G., Wei, S.-H., Zunger, A., (1991) Int. J. Opt. Sens., 5, p. 34Metropolis, N., Rosenbluth, A.W., Rosenbluth, M.N., Teller, A.H., Teller, E., (1953) J. Chem. Phys., 21, p. 1087Cowley, J.M., (1950) J. Appl. Phys., 21, p. 2

Seasonal Occurrence and Distribution on Grapevine Roots of Eurhizococcus brasiliensis (Wille) (Hemiptera: Margarodidae) in Brazil

The ground pearl, Eurhizococcus brasiliensis (Wille) (Hemiptera: Margarodidae), is the most importantgrapevine pest in Brazil. Its seasonal occurrence and distribution on the roots of the different developmentstages were determined to allow better monitoring of this insect and better targeting of its vulnerable lifestages. Yellow cysts (after the first nymphal moult) showed the lowest density in October, followed by agradual increase towards August. White cysts (cysts with enclosed pre-pupal males or females) occurredfrom August to December, with a peak in November. Mobile females (adult females emerging from thewhite cysts) were found from August to December, with a peak in August. Parthenogenetic females thatremain in the ruptured white cysts for egg laying were present from August to April, with a peak inNovember. Mobile nymphs (first instar) were also found from August to April, with a peak in December.Yellow cysts were most abundant at depths of 0 to 25 cm. The horizontal survey showed that cysts occurredmostly on the trunk below the ground (trunk of the rootstock), and that almost all occurred in an area of20 cm width around the trunk. These results provide important information for better monitoring of thispest and to develop better methods for and timing of chemical control

Partial characterization and anticoagulant activity of a heterofucan from the brown seaweed Padina gymnospora

The brown algae Padina gymnospora contain different fucans. Powdered algae were submitted to proteolysis with the proteolytic enzyme maxataze. The first extract of the algae was constituted of polysaccharides contaminated with lipids, phenols, etc. Fractionation of the fucans with increasing concentrations of acetone produced fractions with different proportions of fucose, xylose, uronic acid, galactose, and sulfate. One of the fractions, precipitated with 50% acetone (v/v), contained an 18-kDa heterofucan (PF1), which was further purified by gel-permeation chromatography on Sephadex G-75 using 0.2 M acetic acid as eluent and characterized by agarose gel electrophoresis in 0.05 M 1,3 diaminopropane/acetate buffer at pH 9.0, methylation and nuclear magnetic resonance spectroscopy. Structural analysis indicates that this fucan has a central core consisting mainly of 3-ß-D-glucuronic acid 1-> or 4-ß-D-glucuronic acid 1 ->, substituted at C-2 with alpha-L-fucose or ß-D-xylose. Sulfate groups were only detected at C-3 of 4-alpha-L-fucose 1-> units. The anticoagulant activity of the PF1 (only 2.5-fold lesser than low molecular weight heparin) estimated by activated partial thromboplastin time was completely abolished upon desulfation by solvolysis in dimethyl sulfoxide, indicating that 3-O-sulfation at C-3 of 4-alpha-L-fucose 1-> units is responsible for the anticoagulant activity of the polymer.Universidade Federal do Rio Grande do Norte Departamento de Bioquímica Laboratório de GlicobiologiaUniversidade Federal do Rio Grande do Norte Departamento de Bioquímica Laboratório de Biotecnologia de Polímeros NaturaisUniversidade Federal de São Paulo (UNIFESP) Escola Paulista de Medicina Departamento de BioquímicaUNIFESP, EPM, Depto. de BioquímicaSciEL

Can near-infrared spectroscopy replace a panel of tasters in sensory analysis of dry-cured bísaro loin?

This study involved a comprehensive examination of sensory attributes in dry-cured Bísaro loins, including odor, androsterone, scatol, lean color, fat color, hardness, juiciness, chewiness, flavor intensity and flavor persistence. An analysis of 40 samples revealed a wide variation in these attributes, ensuring a robust margin for multivariate calibration purposes. The respective near-infrared (NIR) spectra unveiled distinct peaks associated with significant components, such as proteins, lipids and water. Support vector regression (SVR) models were methodically calibrated for all sensory attributes, with optimal results using multiplicative scattering correction pre-treatment, MinMax normalization and the radial base kernel (non-linear SVR model). This process involved partitioning the data into calibration (67%) and prediction (33%) subsets using the SPXY algorithm. The model parameters were optimized via a hybrid algorithm based on particle swarm optimization (PSO) to effectively minimize the root-mean-square error (RMSECV) derived from five-fold cross-validation and ensure the attainment of optimal model performance and predictive accuracy. The predictive models exhibited acceptable results, characterized by R-squared values close to 1 (0.9616–0.9955) and low RMSE values (0.0400–0.1031). The prediction set’s relative standard deviation (RSD) remained under 5%. Comparisons with prior research revealed significant improvements in prediction accuracy, particularly when considering attributes like pig meat aroma, hardness, fat color and flavor intensity. This research underscores the potential of advanced analytical techniques to improve the precision of sensory evaluations in food quality assessment. Such advancements have the potential to benefit both the research community and the meat industry by closely aligning their practices with consumer preferences and expectations.This research was funded by “BisOlive: Use of olive pomace in the feeding of Bísaro swine. Evaluation of the effect on meat quality” project. NORTE-01-0247-FEDER-072234. Financial support under the CIMO project (UIDB/00690/2020).info:eu-repo/semantics/publishedVersio

Simulation of a solid sorption ice-maker based on the novel composite sorbent "lithium chloride in silica gel pores"

In this paper, a novel composite sorbent "lithium chloride in silica gel pores” is proposed for application in solar-powered adsorptive ice makers. A mathematical model was used in order to calculate the performance of an ice-maker using this material as adsorbent and methanol as adsorbate. The results of the model showed that a maximum solar coefficient of performance (COPs) of 0.33 and a maximum daily ice production (DIP) of 20 kg/m2 can be obtained for an ice-maker equipped with a solar collector area of 1.5 m2 and 36 kg of adsorbent material. Such performance are noticeably higher than those obtained using commercial activated carbon, that is the adsorbent mostly proposed till now