10 resultados para 70799


Relevância:

10.00% 10.00%

Publicador:

Relevância:

10.00% 10.00%

Publicador:

Resumo:

A kinetic model is developed with the goal of understanding and predicting the morphology evolution of nonocrystals in nonequilibrium growth conditions. The model is based on the assumption that under such conditions, different crystal planes have different kinetic parameters. This model focuses on the morphology-developing stage and is successfully related to the nucleation process and other crystal evolution mechanisms. It is believed to be a universal model and is applied to discuss the morphology evolution of CdSe nanocrystals, including the aspect ratio, injection I schemes, ligands effect and morphology distribution.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

El fenómeno de la transferencia en el aprendizaje es una de las cuestiones que más interesan a la investigación didáctica. Por otro lado también se trata de conocer cómo la nueva técnica de la enseñanza programada facilita o dificulta la transferencia del aprendizaje. La transferencia consiste en traspasar y aplicar a una situación concreta, conocimientos adquiridos en una situación distinta. Uno de los aspectos centrales de la transferencia es conseguir que los alumnos hayan aprendido uno o varios métodos con los que enfrentarse a cualquier problema académico, laboral o de la vida diaria. Se realiza un recorrido histórico por la educación, desde el mundo helénico, hasta nuestros días, pasando por la aportación de John Locke en el siglo XVII, para después sintetizar el proceso histórico que ha determinado el desarrollo de la enseñanza programada y la transferencia. Punto fundamental para el éxito de la transferencia educativa, es una buena organización de la materia o disciplina que se imparta. Por otro lado la educación programada destaca por la capacidad que da al alumno para corregir de manera inmediata lo que ha realizado. Esto tiene consecuencias en la transferencia, ya que cuanto más exactos sean los resultados obtenidos mediante un proceso de aprendizaje, más sustancial será el proceso de transferencia. Por último, el conocimiento del método didáctico que se utiliza por parte del alumno, capacita a éste para poder resolver situaciones problemáticas en el futuro.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

The dinuclear azido-palladium(II) complex [Pd2(N3)4(PPh3)2(μ-ted)], where PPh3 = triphenylphosphine and ted = triethylenediamine, was synthesized and characterized by single-crystal X-ray diffraction. The title compound was crystallized in a triclinic system, space group P1 with a = 11.5875(2)Å, b = 13.0817(3)Å, c = 15.2618(3)Å, α = 93.306(2)°, β =110.040(1)°, γ = 98.486(1)°, V = 2134.95(8)Å3, Z = 2. Each Pd(II) center displays a distorted squareplanar coordination environment formed by two N atoms from two trans terminally coordinated azido groups, one P atom from the phosphine and one N atom from the bridging ted ligand. 2008 © The Japan Society for Analytical Chemistry.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Spermadhesins belong to a novel family of secretory proteins of the male genital tract. They are major proteins of the seminal plasma and have been found peripherally associated to the sperm surface. So far, they have only been detected in ungulates, specifically in pig, cattle, and horse, respectively. Spermadhesins form a subgroup of the superfamily of proteins with a CUB-domain that has been found in a variety of developmentally regulated proteins. The structure and function of the spermadhesins have been investigated in the pig. They are multifunctional proteins showing a range of ligand-binding abilities, e.g. to carbohydrates, phospholipids, and protease inhibitors, suggesting that they may be involved in different steps of fertilization. We report here the genomic organization of the porcine spermadhesin gene cluster as well as a detailed comparative analysis with respect to other mammalian species. The porcine spermadhesin genes are located on SSC 14q28-q29 in a region syntenic to HSA 10q26. The pig contains five closely linked spermadhesin genes, whereas only two spermadhesin genes are present in the cattle genome. Inactive copies of spermadhesin genes are still detectable in the human, chimp, and dog genome while the corresponding region was lost from the rodent genomes of mouse and rat. Within the pig, the five spermadhesin genes contain both highly diverged and highly conserved regions. Interestingly, the pattern of divergence does not correlate with the position of the exons. Evolutionary analyses suggest that the pattern of diversity is shaped by ancestral variation, recombination, and new mutations.

Relevância:

10.00% 10.00%

Publicador:

Relevância:

10.00% 10.00%

Publicador: