Thermal lens technique to evaluate the fluorescence quantum yield of a schiff base

The fluorescence spectrum of the schiff base obtained from salicylaldehyde and 2-aminophenol is studied using an argon-ion laser as the excitation source and its fluorescence quantum yield (Qf) is determined using a thermal lens method. This is a nondestructive technique that gives the absolute value of Qf without the need for a fluorescence standard. The quantum-yield values are calculated for various concentrations of the solution in chloroform and also for various excitation wavelengths. The value of Qf is relatively high, and is concentration dependent. The maximum value of Qf obtained is nearly 0.78. The high value of the fluorescence quantum yield will render the schiff base useful as a fluorescent marker for biological applications. Photostability and gain studies will assess its suitability as a laser dye.

Studies on some new Schiff base complexes of ruthenium and neodymium

In the present study an attempt has been made to synthesize some simple complexes of multidentate ligands. Analogous zeolite encapsulated complexes were also synthesized and characterized. Immobilization on to polymer supports through covalent attachment is expected to solve the problem of decomposition of many complexes during catalytic reaction. Hence the work is also extended to the synthesis and characterization of some polymer supported complexes of Schiff base Iigands. All the three types of synthesized complexes, simple, zeolite encapsulated and polystyrene anchored, were subjected to catalytic activity study towards catechol-oxidation reaction. A selected group of complexes were also screened for their catalytic activity towards phenol-oxidation reaction. Biological screening of the synthesized ligands and neat complexes were done with a view to establish the effect of complexation on biological systems.

Simple and Encapsulated Transition Metal Complexes of Schiff Bases Derived from Quinoxaline-2-Carboxaldehyde and Diamines: Biological and Catalytic Activity Studies

This thesis is mainly concerned with the synthesis and characterisation of new simple and zeolite encapsulated transition metal (manganese(II),nickel(II),and copper(II)complexes of quinoxaline based double Schiff base ligands.Theses ligands are N,N'-bis(quinoxaline-2-carboxalidene)hydrazine,N,N'-bis(quinoxaline-2-carboxalidene)-1,2-diaminoethane,N,N'-bis(quinoxaline-2-carboxalidene)-1,3-diamonopropane,N,N'-bis(quinoxaline-2-carboxalidene)-1,4-diaminobutane,N,N'-bis(quinoxaline-2-carboxalidene)-1,2-diaminocyclohexane and N,N'-bis(quinoxaline-2-carboxalidene)-1,2-diaminobenzene.The Schiff base ligands have been characterised by spectral and single crystal XRD studies.Theses ligands provide great structural diversity during complexation.Mn(II) and Ni(II) form octahedral with these Schiff bases,whereas Cu(II) forms both octahedral and tetrahedral complexes.Studies on the biological and Catalytic activity of the copper(ll) complexes are also presented in this thesis.

Acid-Base. Surface Electron Donatin6 &.Catai.Ytlc Properties Of Some Binary Mixed Oxides Containing Rare Earth Elements

Catalysis research underpins the science of modern chemical processing and fuel technologies. Catalysis is commercially one of the most important technologies in national economies. Solid state heterogeneous catalyst materials such as metal oxides and metal particles on ceramic oxide substrates are most common. They are typically used with commodity gases and liquid reactants. Selective oxidation catalysts of hydrocarbon feedstocks is the dominant process of converting them to key industrial chemicals, polymers and energy sources.[1] In the absence of a unique successfiil theory of heterogeneous catalysis, attempts are being made to correlate catalytic activity with some specific properties of the solid surface. Such correlations help to narrow down the search for a good catalyst for a given reaction. The heterogeneous catalytic performance of material depends on many factors such as [2] Crystal and surface structure of the catalyst. Thermodynamic stability of the catalyst and the reactant. Acid- base properties of the solid surface. Surface defect properties of the catalyst.Electronic and semiconducting properties and the band structure. Co-existence of dilferent types of ions or structures. Adsorption sites and adsorbed species such as oxygen.Preparation method of catalyst , surface area and nature of heat treatment. Molecular structure of the reactants. Many systematic investigations have been performed to correlate catalytic performances with the above mentioned properties. Many of these investigations remain isolated and further research is needed to bridge the gap in the present knowledge of the field.

“Studies on new base materials for microcellular soles"

The most important part of any footwear is the sole (or sole and heel) which withstands all the hannful external factors such as rouglmess of the ground or road, sharp objects, thorns and stones, heat, dampness and cold during walking. The properties desirable in soling material, therefore, would be 1. lightness 2. resistance to wear and tear for long service life 3. flexibility/softness for wearing comfort 4. thennal insulation Rubber soling surpasses all other soling materials in better performance and lower cost. Because MC sole is soft and very light, and has good abrasion resistance, flex properties and set behaviour it has become very popular all over the world and demand for better quality product is ever increasing. Due to the traditional approach adopted by the footwear industry in foot wear design, the rubber based footwear export surprisingly contributes only a small percentage. The essence of success for any industry lies in the expansion of the export market. Microcellular soles are manufactured for the last three decades without much change in the traditional design and colour pattern. In recent years domestic customers have also started demanding better quality products. In view of the changing taste of the customer and growing competition from other countries, substantial improvement in the export potential will require new base materials for regular or fashion rubber based footwears. The main objective of the present study is to develop new base materials for making MC soles with good quality, viz., light weight, durability and bright colours

HDPE-Ash Nanocomposites

Ash-based polymer composites are assuming increasing importance because of the pollutant potential, fine particle size, and low price of ash. Fly ash and rice husk ash are two prominent ash materials on which some investigations have already been done for potential use in polymer composites. This article highlights the results of a study on the use of wood ash in HDPE. Wood ash is mainly a mixture of various metallic compounds and some silica. Here, the characterization of wood ash has been done with the help of XRD, ICPAES, light scattering based particle size analysis, FTIR, and SEM. The results show that wood ash particle size has an average value of 293 nm, much lower than other categories of ash. When blended with HDPE in the presence of a compatibilizer, wood ash gives rise to vastly improved mechanical properties over that of the base polymer. The results prove that wood ash is a valuable reinforcing material for HDPE and the environmental pollution due to wood ash can be solved in a most profitable way by this technique.

Synthesis, Characterization and Applications of Modified TiO2 Systems

This thesis is divided in to 9 chapters and deals with the modification of TiO2 for various applications include photocatalysis, thermal reaction, photovoltaics and non-linear optics. Chapter 1 involves a brief introduction of the topic of study. An introduction to the applications of modified titania systems in various fields are discussed concisely. Scope and objectives of the present work are also discussed in this chapter. Chapter 2 explains the strategy adopted for the synthesis of metal, nonmetal co-doped TiO2 systems. Hydrothermal technique was employed for the preparation of the co-doped TiO2 system, where Ti[OCH(CH3)2]4, urea and metal nitrates were used as the sources for TiO2, N and metals respectively. In all the co-doped systems, urea to Ti[OCH(CH3)2]4 was taken in a 1:1 molar ratio and varied the concentration of metals. Five different co-doped catalytic systems and for each catalysts, three versions were prepared by varying the concentration of metals. A brief explanation of physico-chemical techniques used for the characterization of the material was also presented in this chapter. This includes X-ray Diffraction (XRD), Raman Spectroscopy, FTIR analysis, Thermo Gravimetric Analysis, Energy Dispersive X-ray Analysis (EDX), Scanning Electron Microscopy(SEM), UV-Visible Diffuse Reflectance Spectroscopy (UV-Vis DRS), Transmission Electron Microscopy (TEM), BET Surface Area Measurements and X-ray Photoelectron Spectroscopy (XPS). Chapter 3 contains the results and discussion of characterization techniques used for analyzing the prepared systems. Characterization is an inevitable part of materials research. Determination of physico-chemical properties of the prepared materials using suitable characterization techniques is very crucial to find its exact field of application. It is clear from the XRD pattern that photocatalytically active anatase phase dominates in the calcined samples with peaks at 2θ values around 25.4°, 38°, 48.1°, 55.2° and 62.7° corresponding to (101), (004), (200), (211) and (204) crystal planes (JCPDS 21-1272) respectively. But in the case of Pr-N-Ti sample, a new peak was observed at 2θ = 30.8° corresponding to the (121) plane of the polymorph brookite. There are no visible peaks corresponding to dopants, which may be due to their low concentration or it is an indication of the better dispersion of impurities in the TiO2. Crystallite size of the sample was calculated from Scherrer equation byusing full width at half maximum (FWHM) of the (101) peak of the anatase phase. Crystallite size of all the co-doped TiO2 was found to be lower than that of bare TiO2 which indicates that the doping of metal ions having higher ionic radius into the lattice of TiO2 causes some lattice distortion which suppress the growth of TiO2 nanoparticles. The structural identity of the prepared system obtained from XRD pattern is further confirmed by Raman spectra measurements. Anatase has six Raman active modes. Band gap of the co-doped system was calculated using Kubelka-Munk equation and that was found to be lower than pure TiO2. Stability of the prepared systems was understood from thermo gravimetric analysis. FT-IR was performed to understand the functional groups as well as to study the surface changes occurred during modification. EDX was used to determine the impurities present in the system. The EDX spectra of all the co-doped samples show signals directly related to the dopants. Spectra of all the co-doped systems contain O and Ti as the main components with low concentrations of doped elements. Morphologies of the prepared systems were obtained from SEM and TEM analysis. Average particle size of the systems was drawn from histogram data. Electronic structures of the samples were identified perfectly from XPS measurements. Chapter 4 describes the photocatalytic degradation of herbicides Atrazine and Metolachlor using metal, non-metal co-doped titania systems. The percentage of degradation was analyzed by HPLC technique. Parameters such as effect of different catalysts, effect of time, effect of catalysts amount and reusability studies were discussed. Chapter 5 deals with the photo-oxidation of some anthracene derivatives by co-doped catalytic systems. These anthracene derivatives come underthe category of polycyclic aromatic hydrocarbons (PAH). Due to the presence of stable benzene rings, most of the PAH show strong inhibition towards biological degradation and the common methods employed for their removal. According to environmental protection agency, most of the PAH are highly toxic in nature. TiO2 photochemistry has been extensively investigated as a method for the catalytic conversion of such organic compounds, highlighting the potential of thereof in the green chemistry. There are actually two methods for the removal of pollutants from the ecosystem. Complete mineralization is the one way to remove pollutants. Conversion of toxic compounds to another compound having toxicity less than the initial starting compound is the second way. Here in this chapter, we are concentrating on the second aspect. The catalysts used were Gd(1wt%)-N-Ti, Pd(1wt%)-N-Ti and Ag(1wt%)-N-Ti. Here we were very successfully converted all the PAH to anthraquinone, a compound having diverse applications in industrial as well as medical fields. Substitution of 10th position of desired PAH by phenyl ring reduces the feasibility of photo reaction and produced 9-hydroxy 9-phenyl anthrone (9H9PA) as an intermediate species. The products were separated and purified by column chromatography using 70:30 hexane/DCM mixtures as the mobile phase and the resultant products were characterized thoroughly by 1H NMR, IR spectroscopy and GCMS analysis. Chapter 6 elucidates the heterogeneous Suzuki coupling reaction by Cu/Pd bimetallic supported on TiO2. Sol-Gel followed by impregnation method was adopted for the synthesis of Cu/Pd-TiO2. The prepared system was characterized by XRD, TG-DTG, SEM, EDX, BET Surface area and XPS. The product was separated and purified by column chromatography using hexane as the mobile phase. Maximum isolated yield of biphenyl of around72% was obtained in DMF using Cu(2wt%)-Pd(4wt%)-Ti as the catalyst. In this reaction, effective solvent, base and catalyst were found to be DMF, K2CO3 and Cu(2wt%)-Pd(4wt%)-Ti respectively. Chapter 7 gives an idea about the photovoltaic (PV) applications of TiO2 based thin films. Due to energy crisis, the whole world is looking for a new sustainable energy source. Harnessing solar energy is one of the most promising ways to tackle this issue. The present dominant photovoltaic (PV) technologies are based on inorganic materials. But the high material, low power conversion efficiency and manufacturing cost limits its popularization. A lot of research has been conducted towards the development of low-cost PV technologies, of which organic photovoltaic (OPV) devices are one of the promising. Here two TiO2 thin films having different thickness were prepared by spin coating technique. The prepared films were characterized by XRD, AFM and conductivity measurements. The thickness of the films was measured by Stylus Profiler. This chapter mainly concentrated on the fabrication of an inverted hetero junction solar cell using conducting polymer MEH-PPV as photo active layer. Here TiO2 was used as the electron transport layer. Thin films of MEH-PPV were also prepared using spin coating technique. Two fullerene derivatives such as PCBM and ICBA were introduced into the device in order to improve the power conversion efficiency. Effective charge transfer between the conducting polymer and ICBA were understood from fluorescence quenching studies. The fabricated Inverted hetero junction exhibited maximum power conversion efficiency of 0.22% with ICBA as the acceptor molecule. Chapter 8 narrates the third order order nonlinear optical properties of bare and noble metal modified TiO2 thin films. Thin films were fabricatedby spray pyrolysis technique. Sol-Gel derived Ti[OCH(CH3)2]4 in CH3CH2OH/CH3COOH was used as the precursor for TiO2. The precursors used for Au, Ag and Pd were the aqueous solutions of HAuCl4, AgNO3 and Pd(NO3)2 respectively. The prepared films were characterized by XRD, SEM and EDX. The nonlinear optical properties of the prepared materials were investigated by Z-Scan technique comprising of Nd-YAG laser (532 nm,7 ns and10 Hz). The non-linear coefficients were obtained by fitting the experimental Z-Scan plot with the theoretical plots. Nonlinear absorption is a phenomenon defined as a nonlinear change (increase or decrease) in absorption with increasing of intensity. This can be mainly divided into two types: saturable absorption (SA) and reverse saturable absorption (RSA). Depending on the pump intensity and on the absorption cross- section at the excitation wavelength, most molecules show non- linear absorption. With increasing intensity, if the excited states show saturation owing to their long lifetimes, the transmission will show SA characteristics. Here absorption decreases with increase of intensity. If, however, the excited state has strong absorption compared with that of the ground state, the transmission will show RSA characteristics. Here in our work most of the materials show SA behavior and some materials exhibited RSA behavior. Both these properties purely depend on the nature of the materials and alignment of energy states within them. Both these SA and RSA have got immense applications in electronic devices. The important results obtained from various studies are presented in chapter 9.

Normative and cognitive influences on female entrepreneurial reluctance at the base of the pyramid - an explorative study of cleaning ladies in Istanbul

Previous research has considered entrepreneurship as a way out of poverty and as a chance to foster economic growth. Moreover, specifically start-ups headed by women have played an important role in the economic development and it has been argued that gender-related issues, amongst others, play a significant role for the performance of a country or region. Against this background, this qualitative study explores desires, reluctances and constraints toward entrepreneurial activities of a comparably homogenous group of potential (poor) entrepreneurs in an emerging economy—cleaning ladies in Istanbul. We focus on this particular context as still rather little is known on reasons why women do not start a business (in Turkey). We believe exploring the reasons why certain individuals choose not to become entrepreneurs is at least as telling as investigating why they do so. We draw upon the social dimensions of entrepreneurship by Shapero and Sokol (1982) alongside Institutional Theory and posit that normative and cognitive forces may shape individual decisions on entrepreneurship. We identified two basic clusters of women and discuss possible hindrance factors undermining entrepreneurial desires and limitations for entrepreneurship as well as possible avenues for policy makers (and MNCs) to foster entrepreneurship in the given community.

El bilingüismo como base de aprendizaje y formación humana en valores.

Se presenta memoria final de proyecto educativo centrada en el aspecto de formación en valores y conocimiento de las culturas, a través de la comunicación lingüística. Se realiza en el CEIP Los Llanos en Almonte, Huelva. Los objetivos son: con el alumnado: facilitar un acercamiento y mejorar el conocimiento de la lengua inglesa y francesa, potenciar el uso fluido y coloquial del inglés, incrementar la oralidad en el segundo idioma, establecer un uso espotáneo de la segunda lengua, ampliar los horizontes culturales y sociales del alumnado por el uso del segundo idioma ampliable a un tercero, poner a nuestro alumnado en contacto con las nuevas tecnologías, dar un tratamiento estructurado a problemas interdisciplinares que lleven a desarrollar el razonamiento, la imaginación y la creatividad de nuestro alumnado, utilizar las tecnologías de la información y la comunicación con el alumnado; respecto al centro escolar: concienciar a toda la comunidad educativa de la importancia del segundo y tercer idiomas como fuente de intercambio de ideas y cultura, anticipar el estudio del segundo idioma hasta los cursos de educación infantil de tres años, conocer y estudiar una tercera lengua, promover la iniciación de las nuevas tecnologías en el centro para dar la familiaridad con las mismas a toda la comunidad educativa e imponer el avenimiento de la condición TIC y DIG de este colegio, incluir la informática en el proyecto curricular de centro en todas las áreas, utilizándolo como un recurso didáctico y motivador, utilizar esta tecnología como medio de perfeccionamiento del profesorado, promover la resolución de conflictos de convivencia, a través del diálogo y la tolerancia, así como el conocimiento de los demás, modificar el proyecto curricular del centro así como sus finalidades educativas en la medida que el consenso de soluciones buscadas por esta actividad lo permitan. El proceso consta de varias fases: primera, se procedió a consensuar el plan de actividades, donde se establecieron las bases correspondientes al manejo y planteamiento de las actividades de este proyecto de innovación de acuerdo con los contenidos y objetivos para las áreas que lo abarcan; segunda fase: buscar y aprender a manejar el software educativo necesario, aprender el uso del programa JClic, empezando a elaborar actividades para su aplicación con el alumnado; tercera fase: conocimiento y experimentación con el alumnado; cuarta fase: se alcanzaron las conclusiones y se valoró la actividad; sucesivas fases: se continuació, si el proceso de evaluación lo estimara conveniente, con la aplicación del programa. El resultado: las conclusiones apuntan a una mayor medida en la formación integral del ser humano que a los conocimientos que pudieren adquirir las personas sometidas a un proceso de enseñanza aprendizaje, siendo este último de gran importancia.

La educación física de base en la enseñanza primaria : conceptos-procedimientos y actividades para su desarrollo.

Estructura del área curricular de educación física para cada uno de los tres ciclos de la educación primaria especificandose los objetivos generales, bloques de contenidos y conceptos básicos a desarrollar con definiciones y objetivos, organización, ejercicios y actividades para cada uno de ellos. Los conceptos trabajados son: esquema corporal, lateralidad, actitud, tono muscular, respiración, relajación, equilibrio, percepción y estructuración espacial, percepción espacio-temporal, coordinación dinámica general y segmentaria.

La Educación Psicomotriz, necesidad de base en el desarrollo personal del niño.

Facilitar a los alumnos de la Escuela Universitaria del Profesorado de EGB una visión actual del tema de psicomotricidad y su importancia en el desarrollo personal del niño desde distintos puntos de vista. El objeto de todo el informe es la Educación Psicomotriz como aspecto importante y necesario para el desarrollo del niño. Educación Psicomotriz como acción pedagógica y psicológica que utiliza el movimiento con el fin de normalizar o mejorar el comportamiento. Para ello divide el estudio en las siguientes partes: 1) Visión del cuerpo en el marco escolar. 2) Simbolismo del movimiento y de la acción. 3) Interés por el estudio del desarrollo motor desde la vertiente fisiológica y psicológica. 4) La psicomotricidad. Concepto. 5) La Educación Psicomotriz. 6) Las progresiones en el ámbito educativo. 7) La psicomotricidad gruesa. 8) El dominio corporal estático. 9) La motricidad fina. 10) Educación del esquema corporal. 11) La psicomotricidad en la escuela. 12) El perfil psicomotor. El dibujo. 13) Modalidades de aplicación de la Educación Psicomotriz: reeducación de los diversos tipos de inadaptación en el niño normal. 14) Inadaptación de los disminuidos físicos. 15) Inadaptación de los deficientes ligeros y medios. En cada apartado ofrece una serie de actividades a realizar así como una serie de actividades de evaluación para la coordinación óculo-manual, dinámica, equilibrio, percepción y lenguaje divididos por edades. Para terminar el autor ofrece un vocabulario y una bibliografía relacionados con el tema de interés para el profesor de EGB. Trata de estudiar la psicomotricidad no sólo en su plano motor sino como algo más que una simple función instrumental que despersonalizaría la función motora. Con el término psicomotor se destaca la participación psíquica en los movimientos expresivos, pero también en los de ejecución de un acto y dependiendo del tipo de individuo. Una vez sintetizados los puntos esenciales sostenidos por especialistas en la materia se realiza un aporte y enfoque que el autor estima que puede ser muy importante sobre todo en lo referente al control respiratorio y técnicas de relajación. Se trata de un material de referencia que puede ser de ayuda para los profesores de EGB en cuanto al tema tratado. Además de ofrecer un vocabulario y una bibliografía del tema ofrece una serie de ejercicios y actividades detalladamente explicados para cada uno de los apartados.

Educación Física de base del ciclo medio.

Aportar una serie de materiales que ayuden y den orientaciones prácticas al profesor de Educación Física del ciclo medio de EGB. Conceptos, ejercicios, actividades y juegos a desarrollar en el área de Educación Física en el ciclo medio de EGB. Este trabajo se divide en cinco grandes apartados: esquema corporal, percepción, coordinación, habilidades motrices específicas, y control y valoración del material a utilizar. En cada apartado suele incluir definiciones y conceptos, y ejercicios, actividades y/o juegos a desarrollar con los alumnos en el aula. Los instrumentos que utiliza son fundamentalmente dibujos, gráficos y esquemas para describir los ejercicios y juegos. También aporta la letra de algunas danzas y canciones asturianas. Propone el uso de algunos materiales como pelotas, aros y cuerdas. Descripción detallada tanto de conceptos como de ejercicios, actividades y juegos. Aporta información y actividades prácticas referidos a temas como la lateralidad, el control del propio cuerpo, la sensibilidad, la respiración, la relajación, la organización espacial y temporal, la coordinación dinámica general, la coordinación óculo-manual, la coordinación óculo-pierna y el equilibrio. Proporciona información y materiales a utilizar en habilidades motrices específicas como la dramatización y la danza y un listado bastante amplio de juegos predeportivos aplicados al atletismo, baloncesto, voleibol, fútbol, gimnasia y balonmano.

Reflexión histórica, antropofilosófica y epistemológica como base para una teoría sistémico-cibernética de la Educación Física.

Fundamentar una teoría de la Educación Física que clarifique su marco científico y sus posibilidades de intervención. Reflexión histórica, antropofilosófica y epistemológica acerca de la Educación Física. Reflexión histórica: estudio del acontecer físico-educativo desde la educación griega hasta nuestros días y estudio comparado de la Educación Física en Platón, Locke y Rousseau. Reflexión antropofilosófica: realización de un juicio crítico a las diferentes teorías sobre el hombre y defensa de la idea del cuerpo como cuerpo en movimiento. Reflexión epistemológica: análisis de las variables epistemológicas a tener en cuenta en la fundamentación científica de la Educación Física. Bibliografía. Síntesis y metodología estructural. Dentro de esta última utiliza la metodología cibernética. Históricamente la Educación Física ha sido considerada como una educación corporal, aunque también se han realizado intentos para unificarla con lo moral e intelectual. Se puede clasificar a los autores en tres grandes grupos: los que le conceden objetivos estrictamente corporales (Aristóteles, Galeno, Mercurial), los que además entienden que impone una actitud ética o moral (Platón, Da Feltre, Vives, Locke, Amorós, Arnold, Coubertin) y los que además creen que influye en la dimensión intelectual (Rousseau). El estudio comparado de la Educación Física en Platón, Locke y Rousseau demuestra que los tres son conscientes de que los objetivos que le otorgan son consecuencia directa del ejercicio físico del niño y además los tres sostienen una concepción idéntica del movimiento humano. Todo saber sistemático que intente profundizar en el conocimiento de la Educación Física debe plantearse dos cuestiones: la primera hace referencia a la motricidad humana y nos lleva a entrar en el campo de las Ciencias de la Motricidad humana: Kinantropología (Cagigal), Praxeología (Parlebas) y Psicokinética (Le Boulch); y la segunda a su dimensión educativa llevándonos al campo de las Ciencias de la Educación. Para el autor, la Educación Física es toda ciencia o actividad que gira en torno al hecho de educar con el empleo del movimiento humano. Propone un modelo cibernético que concibe la relación físico-educativa como una acción deliberada en un marco abierto y que constaría de tres momentos claves: percepción, decisión y actuación. Se puede encuadrar la Educación Física en el contexto de las Ciencias de la Educación con innegable carácter científico propio. El elemento compendiador que da sentido unívoco a la Educación Física es el movimiento humano. La cibernética es un instrumento metodológico válido para estudiar el fenómeno educativo-motor y permite sentar las bases de una Educación Física funcional.

Estudio de los nexos lingüísticos en el lenguaje escrito : base para una intervención didáctica.

Estudio del desarrollo de los nexos lingüísticos dentro de la expresión escrita, desarrollo de los nexos gramaticales y sus posibles connotaciones con el desenvolvimiento de otros factores personales. Niños pertenecientes a un ambiente urbano y el otro grupo al ambiente rural; un total de 826 sujetos de los tres ciclos de EGB. Realización de ejercicios de redacción por los niños, espaciando unos días la ejecución de tres ejercicios para que se emplearan todos los recursos lingüísticos. Después se analizan los tipos de nexos que aparecían y su frecuencia. Realización, por parte de los alumnos, de una redacción sobre una excursión, resumen de una historieta leída por el profesor, creación de una historieta. Las diferencias entre las dos muestras sociográficas son pequeñas, inclinándose a favor de la muestra sociográfica urbana. En cuanto a los ciclos, el uso de la coordinación copulativa, es mayoritaria en los dos primeros ciclos. Las derivaciones didácticas indican la dependencia de las fuentes presentadas en el primer ciclo. En el segundo, el uso de los nexos lingüísticos es más rico y en el tercero se instalan de forma definitiva los nexos lingüísticos. La variable descriptiva tiene un comportamiento diferente según se refiera al uso de los nexos prepositivos o conjuntivos, la variable creativa es superior debido al uso de nexos conjuntivos.