Absolute science : pupil book 3.

Ofrece una gran flexibilidad y apoyo para la enseñanza y el aprendizaje de las ciencias y garantiza una transición fluida de la etapa dos a la etapa tres. Todos los capítulos, en el texto del alumno, cuentan con una amplia gama de funciones: las actividades de iniciación al comienzo de cada capítulo que ilustra la ciencia en el mundo real; preguntas de cada capítulo para reforzar el conocimiento; preguntas para toda la clase o grupo de discusión; consejos, sugerencias y recordatorio del aprendizaje anterior. Al final del capítulo preguntas y resumen de las principales ideas y palabras clave para consolidar los conocimientos.

Absolute science : Year 8 : complete teacher pack CD-Rom.

Este CD-ROM recoge todo el material a partir del año ocho del libro del profesor no especialista. contiene: una detallada lista de temas de cada capítulo que acompaña a las notas del profesor; consejos y sugerencias para la enseñanza; planificación de lecciones contienen actividades de iniciación, junto con las tareas propuestas. Un resumen de las notas para cada lección. Al final de la unidad hoja de registro de la prueba.

Absolute science. Pupil book 1.

Ofrece una gran flexibilidad y apoyo para la enseñanza y el aprendizaje de las ciencias y garantiza una transición fluida de la etapa clave dos /Key Stage 2) a la etapa clave tres (Key Stage 3). Todos los capítulos cuentan con una amplia gama de actividades: de iniciación a la ciencia en el mundo real; preguntas para reforzar el conocimiento ; preguntas para toda la clase o grupo de discusión ; consejos, sigerencias y recordatorio del aprendizaje anterior. Al final del capítulo hay preguntas y resumen de las principales ideas y palabras clave para consolidar los conocimientos adquiridos.

Absolute science : year 7 : complete teacher pack CD-ROM.

CD-ROM donde se recoge todo el material para la transición del nivel dos (Key Stage 2) al nivel tres (Key Stage 3). Contiene una lista detallada de temas de cada capítulo que acompaña a las notas del profesor; consejos y sugerencias para la enseñanza; planificación de lecciones con actividades de iniciación, junto con las tareas propuestas; Un resumen de las notas para cada lección. Al final de la unidad hoja de registro de la prueba.

Layers of generality and types of generalization in pattern activities. 'Niveles de generalidad y tipos de generalizaciones en actividades de patrones'.

Resumen basado en el de la publicación

Direct time-resolved study of the gas-phase reactions of germylene with ethyl- and diethylgermane: absolute rate constants, temperature dependences, and mechanism

Time-resolved studies of germylene, GeH2, generated by the 193 nm laser flash photolysis of 3,4-dimethyl-1-germacyclopent-3-ene, have been carried out to obtain rate constants for its bimolecular reactions with ethyl- and diethylgermanes in the gas phase. The reactions were studied over the pressure range 1-100 Torr with SF6 as bath gas and at five temperatures in the range 297-564 K. Only slight pressure dependences were found for GeH2 + EtGeH3 (399, 486, and 564 K). The high pressure rate constants gave the following Arrhenius parameters: for GeH2 + EtGeH3, log A = -10.75 +/- 0.08 and E-a = -6.7 +/- 0.6 kJ mol(-1); for GeH2 + Et2GeH2, log A = -10.68 +/- 0.11 and E-a = -6.95 +/- 0.80 kJ mol(-1). These are consistent with fast, near collision-controlled, association processes at 298 K. RRKM modeling calculations are, for the most part, consistent with the observed pressure dependence of GeH2 + EtGeH3. The ethyl substituent effects have been extracted from these results and are much larger than the analogous methyl substituent effects in the SiH2 + methylsilane reaction series. This is consistent with a mechanistic model for Ge-H insertion in which the intermediate complex has a sizable secondary barrier to rearrangement.

Gas phase kinetic and quantum chemical studies of the reactions of silylene with the methylsilanes. Absolute rate constants, temperature dependences, RRKM modelling and potential energy surfaces

Time resolved studies of silylene, SiH2, generated by the 193 nm laser. ash photolysis of phenylsilane, have been carried out to obtain rate coefficients for its bimolecular reactions with methyl-, dimethyl- and trimethyl-silanes in the gas phase. The reactions were studied over the pressure range 3 - 100 Torr with SF6 as bath gas and at five temperatures in the range 300 - 625 K. Only slight pressure dependences were found for SiH2 + MeSiH3 ( 485 and 602 K) and for SiH2 + Me2SiH2 ( 600 K). The high pressure rate constants gave the following Arrhenius parameters: [GRAPHICS] These are consistent with fast, near to collision-controlled, association processes. RRKM modelling calculations are consistent with the observed pressure dependences ( and also the lack of them for SiH2 + Me3SiH). Ab initio calculations at both second order perturbation theory (MP2) and coupled cluster (CCSD(T)) levels, showed the presence of weakly-bound complexes along the reaction pathways. In the case of SiH2 + MeSiH3 two complexes, with different geometries, were obtained consistent with earlier studies of SiH2 + SiH4. These complexes were stabilised by methyl substitution in the substrate silane, but all had exceedingly low barriers to rearrangement to product disilanes. Although methyl groups in the substrate silane enhance the intrinsic SiH2 insertion rates, it is doubtful whether the intermediate complexes have a significant effect on the kinetics. A further calculation on the reaction MeSiH + SiH4 shows that the methyl substitution in the silylene should have a much more significant kinetic effect ( as observed in other studies).

Total synthesis of (+/-) maculalactone A, maculalactone B and maculalactone C and the determination of the absolute configuration of natural (+) maculalactone A by asymmetric synthesis

Maculalactones A, B and C from the marine cyanobacterium Kyrtuthrix maculans are amongst the only compounds based on the tribenzylbutyrolactone skeleton known in nature and (+) maculalactone A from the natural source possesses significant biological activity against various marine herbivores and marine settlers. We now report a concise synthesis of racemic maculalactone A in five steps from inexpensive starting materials. Maculalactones B and C were synthesized by a minor modification to this procedure, and the synthetic design also permitted an asymmetric synthesis of maculalactone A to be achieved in around 85% ee. The (+) and (-) enantiomers of maculalactone A were assigned, respectively, to the S and R configurations on the basis of the chiral selectivity expected for catecholborane reduction of an unsymmetrical ketone in the presence of Corey's oxazoborolidine catalyst. Surprisingly, it appeared that natural (+) maculalactone A was biosynthesized in K. maculans in a partially racemic form, comprising ca. 90-95% of the (S) enantiomer and 5-10% of its (R) enantiomer. Coincidentally therefore, the percentage enantiomeric excess of the product obtained from asymmetric synthesis almost exactly matched that found in nature. (C) 2004 Elsevier Ltd. All rights reserved.

Effects of presenting the baseline risk when communicating absolute and relative risk reductions

This study compares relative and absolute forms of presenting risk information about influenza and the need for vaccination. It investigates whether differences in people's risk estimates and their evaluations of risk information, as a result of the different presentation formats, are still apparent when they are provided with information about the baseline level of risk. The results showed that, in the absence of baseline information, the relative risk format resulted in higher ratings of satisfaction, perceived effectiveness of vaccination, and likelihood of being vaccinated. However, these differences were not apparent when baseline information was presented. Overall, provision of baseline information resulted in more accurate risk estimates and more positive evaluations of the risk messages. It is recommended that, in order to facilitate shared and fully informed decision making, information about baseline level of risk should be included in all health communications specifying risk reductions, irrespective of the particular format adopted.