Transfer-based models implementation in an equation oriented package

A general transfer based model for L-V and L-L operations was developed in our Equation-Oriented simulator CheOpe and used to analyze several EniChem processes. By the practical use we confirm that these models generally improve usability of a general-purpose simulator. Thanks to the cell approach of CheOpe we can easily analyze different equipment structures or change the level of detail of equipment. Several solution methods of Maxwell-Stefan equations and several effective methods have been implemented. By the analysis of the model behaviour on the basis of many industrial applications, we have found not very significant differences in simulation and design of some non reactive distillation columns using Maxwell-Stefan equations or simpler models that neglect interactions in the mass transfer rate equations. In simulation and design of a reactive system with fast reactions, reaction-transfer interactions cannot be neglected, but often approximate models analytically solved give results as good as more complex models.     

School readiness and later achievement: Replication and extension using a nationwide Canadian survey.

In this article we replicate and extend findings from Duncan et al. (2007). The 1st study used Canada-wide data on 1,521 children from the National Longitudinal Survey of Children and Youth (NLSCY) to examine the influence of kindergarten literacy and math skills, mother-reported attention, and mother-reported socioemotional behaviors on 3rd-grade math and reading outcomes. Similar to Duncan et al., (a) math skills were the strongest predictor of later achievement, (b) literacy and attention skills predicted later achievement, and (c) socioemotional behaviors did not significantly predict later school achievement. As part of extending the findings, we incorporated a multiple imputation approach to handle missing predictor variable data. Results paralleled those from the original study in that kindergarten math skills and Peabody Picture Vocabulary Test—Revised scores continued to predict later achievement. However, we also found that kindergarten socioemotional behaviors, specifically hyperactivity/impulsivity, prosocial behavior, and anxiety/depression, were significant predictors of 3rd-grade math and reading. In the 2nd study, we used data from the NLSCY and the Montreal Longitudinal-Experimental Preschool Study (MLEPS), which was included in Duncan et al., to extend previous findings by examining the influence of kindergarten achievement, attention, and socioemotional behaviors on 3rd-grade socioemotional outcomes. Both NLSCY and MLEPS findings indicated that kindergarten math significantly predicted socioemotional behaviors. There were also a number of significant relationships between early and later socioemotional behaviors. Findings support the importance of socioemotional behaviors both as predictors of later school success and as indicators of school success. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

"School readiness and later achievement": Correction to Duncan et al. (2007).

Reports an error in "School readiness and later achievement" by Greg J. Duncan, Chantelle J. Dowsett, Amy Claessens, Katherine Magnuson, Aletha C. Huston, Pamela Klebanov, Linda S. Pagani, Leon Feinstein, Mimi Engel, Jeanne Brooks-Gunn, Holly Sexton, Kathryn Duckworth and Crista Japel (Developmental Psychology, 2007[Nov], Vol 43[6], 1428-1446). The DOI for the supplemental materials was printed incorrectly. The correct DOI is as follows: http://dx.doi.org/10.1037/0012-1649.43.6.1428.supp. (The following abstract of the original article appeared in record 2007-16709-012.) Using 6 longitudinal data sets, the authors estimate links between three key elements of school readiness--school-entry academic, attention, and socioemotional skills--and later school reading and math achievement. In an effort to isolate the effects of these school-entry skills, the authors ensured that most of their regression models control for cognitive, attention, and socioemotional skills measured prior to school entry, as well as a host of family background measures. Across all 6 studies, the strongest predictors of later achievement are school-entry math, reading, and attention skills. A meta-analysis of the results shows that early math skills have the greatest predictive power, followed by reading and then attention skills. By contrast, measures of socioemotional behaviors, including internalizing and externalizing problems and social skills, were generally insignificant predictors of later academic performance, even among children with relatively high levels of problem behavior. Patterns of association were similar for boys and girls and for children from high and low socioeconomic backgrounds. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Molecular rearrangements in extrusion processes for the production of amaranth-enriched,gluten-free rice pasta

Gluten-free pasta represents a challenge for food technologists and nutritionists since gluten-free materials used in conventional formulations have poor functional and nutritional properties. A novel extrusion-cooking process was set up to improve the textural characteristics of rice-based pasta, and to enrich it with amaranth. Mineral and fiber content, and protein digestibility were improved by amaranth enrichment. Extrusion-cooking of a 75/25 mixture of rice flour and amaranth prior to pasta-making gave the best results as for the textural characteristics of the final product. The firmness of cooked pasta increased due to the extrusion-cooking process, that also decreased protein solubility in the amaranth-enriched pasta. The content in accessible thiols also decreased in amaranth-enriched pastas, indicating that amaranth proteins may be involved in forming disulphide bonds during the pasta-making process. Our results suggest that starch in rice flour interacts best with amaranth proteins when starch gelatinization occurs simultaneously to protein denaturation in the extrusion-cooking process.     

Fermentation modifies protein/protein and protein/starch interactions in sorghum dough

A study was made on the molecular and structural changes occurring in the protein and starch components of sorghum flour when fermented to prepare typical non-malted Sudanese foods. Protein solubility and SDS-PAGE studies indicated that water-soluble proteins are the main target of hydrolysis during fermentation. Proteolysis products are taken up for bacterial growth. Kafirins are among the proteins left intact by proteolytic events in the fermentation step. Upon cooking in boiling water kafirins are converted into protein aggregates almost insoluble even in the presence of 8 M urea and of disulphide-reducing agents. Viscoamylographic and microstructural studies indicate that fermentation leads to the release of starch granules from very compact structures in the original sorghum flour, in which proteolysis-sensitive, water-soluble proteins form an essential part of the outermost shell of large structures, where starch granules are embedded into a kafirin-rich protein matrix that is not affected by proteolytic events during fermentation.     

Information storage based on photochemical effects in mixed Langmuir–Blodgett films

Mixed Langmuir–Blodgett (LB) films of two novel thiophene-spaced N-alkylpyridinium malononitrile zwitterionic dyes have been prepared. The LB films present two sharp, non-overlapping charge-transfer absorption bands which can be selectively photobleached in a irreversible fashion. The former could have potential application in multifrequency optical data storage.     

Cardiac autonomic patterns preceding occasional vasovagal reactions in healthy humans

BACKGROUND: The wide range of clinical presentation of orthostatic vasovagal syncope suggests different underlying changes in the cardiac autonomic modulation. METHODS AND RESULTS: To evaluate the beat-by-beat modifications in the neural control of heart period preceding a syncopal event, we studied RR interval variability in 22 healthy subjects who experienced fainting for the first time during a 90 degrees head-up tilt and in 22 control subjects by means of time-variant power spectral analysis. Sympathetic and vagal modulations to the sinoatrial node were assessed by the normalized power of the low-frequency (LF, approximately 0.1-Hz) and high-frequency (HF, approximately 0.25-Hz) oscillatory components of RR variability. When the patients were supine, no differences were observed in the hemodynamic and spectral parameters of the 2 groups. During the tilt procedure, RR, LFNU, and HFNU (NU=normalized units) values were relatively stable in control subjects. During early tilt (T1), subjects with syncope had reduced RR intervals compared with control subjects. In 13 subjects with syncope, RR decreased while LFNU and LF/HF increased in the last minute of tilt before syncope (T2). Conversely, in the remaining 9 fainters, LFNU and LF/HF decreased from T1 to T2 and HFNU increased slightly. CONCLUSIONS: Two different patterns may be recognized in the cardiac autonomic changes preceding an occasional vasovagal event, namely, one characterized by a progressive increase of the marker of cardiac sympathetic modulation up to the onset of syncope, the other by a sympathetic inhibition with an impending vagal predominance. The recognition of different pathophysiological mechanisms in fainters may have important therapeutic implications.