Adsorption kinetic investigations of phthalocyanine derivatives self assembled monolayers (SAMs) on gold: Temperature influence on the SAM formation process and quality

The ordered nano-structured surfaces, like self-assembled monolayers (SAMs) are of a great scientific interest, due to the low cost, simplicity, and versatility of this method. SAMs found numerous of applications in molecular electronics, biochemistry and optical devices. Phthalocyanine (Pc) complexes are of particular interest for the SAM preparation. These molecules exhibit fascinating physical properties and are chemically and thermally stable. Moreover their complex structure is advantageous for the fabrication of switchable surfaces. In this work the adsorption process of Pcs derivatives, namely, subphthalocyanines (SubPcB) and terbium (2TbPc) sandwich complexes on gold has been investigated. The influence of the molecular concentration, chain length of peripheral groups, and temperature on the film formation process has been examined using a number of techniques. The SAMs formation process has been followed in situ and in real time by means of second harmonic generation (SHG) and surface plasmon resonance (SPR) spectroscopy. To investigate the quality of the SAMs prepared at different temperatures atomic force microscopy (AFM) and X-Ray photoelectron spectroscopy (XPS)measurements were performed. Valuable information about SubPcB and 2TbPc adsorbtion process has been obtained in the frame of this work. The kinetic data, obtained with SHG and SPR, shows the best conformance with the first order Langmuir kinetic model. Comparing SHG and SPR results, it has been found, that the film formation occurs faster than the formation of chemical bonds. Such, the maximum amount of molecules on the surface is reached after 6 min for SubPcB and 30 min for 2TbPc. However, at this time the amount of formed chemicals bonds is only 10% and 40% for SubPcB and 2TbPc, respectively. The most intriguing result, among others, was obtained at T = 2 °C, where the formation of the less dense SAMs have been detected with SHG.However, analyzing XPS and AFM data, it has been revealed, that there is the same amount of molecules on the surface at both temperature T = 2 °C, and T = 21 °C, but the amount of formed chemicals bond is different. At T = 2 °C molecules form aggregates, therefore many of available anchor groups stay unattached.

Problems with large groups

A list of considerations on the problems with large groups. This material was sent to Debra Morris in 2007, by David Jaques, an educationist with many years' experience of working with groups.

Les activitats nàutiques i les persones amb hipoacúsia : una experiència amb focus groups.

Resumen tomado del autor

Interviews And Focus Groups: Purpose Paradigms Protocols and Pragmatics

Introduction to interview data, how it is used and how and why it might be collected

INFO2009 - Team 'DROP TABLE groups;

Edshare for INFO2009 coursework 2 - Team 'DROP TABLE groups;

W3 Working in Groups

Slides, notes and links summarising presentation, discussions, activities and further reading

Variación de la violencia sexual en tiempos de guerra: la violación en la guerra no es inevitable

La violencia sexual varía dramáticamente de una guerra a otra, y, en ocasiones, de un grupo armado a otro dentro de una misma guerra. Sin embargo, en algunos conflictos la violencia sexual perpetrada por determinados grupos armados es especialmente limitada, pese aque estos cometen otro tipo de violencia contra civiles. Ciertos grupos cometen actos de violencia sexual solo contra mujeres, mientras que otros también lo hacen contra hombres. Los científicos sociales están documentando y analizando con una frecuencia cada vez mayor esta variación en los patrones de violencia sexual en tiempos de guerra, particularmente en cuanto a las distintas dimensiones de violencia (su forma, frecuencia, blancos ypropósitos), así como en lo referente a los cambios en estos cuatro patrones a través del tiempo. Por tal razón, en este texto, en primer lugar, introduzco conceptos clave, incluyendo estas cuatro dimensiones y el concepto de violencia sexual como práctica (un patrón que no es ordenado pero sí tolerado por los comandantes, y que ocurretanto en casos en los que hay beneficios estratégicos como en los que no los hay). Después, resumo brevemente las investigaciones recientes que documentan patronesde violencia sexual en tiempos de guerra. Tras mostrar que muchos abordajes presentes en la literatura publicada no dan cuenta de la variación observada –dehecho, muchos predicen más violencia sexual que los trágicos niveles observados–,propongo un marco teórico centrado en las dinámicas internas de los grupos armados. Luego, analizo las condiciones en las cuales los grupos armados no llevan a cabo violaciones, aquellas en las que realizan violaciones estratégicas y aquellas en las que las violaciones se cometen como práctica. A lo largo del artículo, me valgo de hallazgos recientes en la literatura de las ciencias sociales, algunos de ellos todavía no publicados. Concluyo con la implicación de este análisis para la formulación de políticas públicas: la variación observada en la violencia sexual en tiempos de guerra, particularmente la ausencia relativa de este tipo de violencia por parte de muchos grupos armados, indica que la violación no es inevitable en la guerra.

Academic stress in master’s students and its modulatory variables: a between-groups design

The present investigation tries to establish the descriptive profile of the academic stress of the students of the masters in education and to identify which sociodemographic and situational variables play a modulator role. This investigation is based on the Person-Surroundings Research Program and the systemical cognitive model of academic stress. The study can be characterized as transectional, correlational and non experimental. The collection of the information was made through the SISCO inventory of Academic Stress which was applied to 152 students. The main results suggest that 95% of the master students report having felt academic stress a few times but with medium-high intensity. Variables gender, civil state, attending masters and institutional support of the attending masters act as modulators in academic stress.

Diagnostic Related Groups (drgs): Resourceful tools for financial crisis times?

This document is intended to be read by the Colombian Ministry of Social Protection (former MoH) and includes some recommendations that could be implemented on the aim to increase allocative efficiency, thus improving macroeconomic performance of the Colombian Health System (CHS). It will be conducted as follows: first it will briefly review the background and actual context of the CHS, after this, will mention some related issues that justify a policy intervention on strategic purchasing to promote long run sustainability and hopefully the future attainment of major goals such as universal coverage and quality improvement. After prioritizing the main financial threats to the system, based on findings from literature review from countries that have successfully implemented similar policies, this paper will make some policy recommendations on regards especially to inpatient health care services in Colombia.

Armed conflict and paramilitary groups in Chiapas

The armed conflict in Chiapas began in 1994 after the armed uprising of the Zapatista Army of National Liberation (EZLN). Until now the Mexican government do not recognize the existence of an armed conflict there, for what they call inter-ethnic violence that happens in different municipalities in Chiapas. This study aims at demonstrating that, first, the Mexican state of Chiapas has an armed conflict since the mid-nineties, which has intensified and transformed over sixteen years. It is in this transformation that have emerged paramilitary groups seeking to destabilize the state, generating dynamics of appropriation and control of territory through different practices such as forced displacements, selective assassinations and terror spread within populations who are the targets of their attacks (mainly community support of the Zapatista Army of National Liberation). This work studied the "Peace and Justice" paramilitary group operating in different parts of the state of Chiapas, mainly in the Northern Zone. This case-study will look at the changes it has undergone Mexican democracy, which will be analyzed at two points: first, the failure of federal and Chiapas state to allow or endorse the creation of paramilitary groups and not to punish their actions; on the other, the consequences of the actions of such actors in democratic institutions, and democracy itself. Will seek to demonstrate that indeed both the permissiveness of the Mexican state and its complicity has weakened democracy in Mexico, since they are not able to manage conflict so that they do not degenerate into violence.

The Proliferation of Paramilitary Groups in Southern Mexico: State Strategy or Struggle between Local Political Elites?

This study traces the origins of Mexican paramilitary groups and argues that, contrary to what most of the literature on the subject implies, they do not represent a state strategy to thwart leftist groups seeking social change. Rather, they represent battles between groups of national and local-level elites with different visions of democracy and of what constitutes good governance. The polarization inherent in this type of conflict leads local actors to have to side with one faction of elites or the other. The presence of radical leftist groups in recently colonized indigenous areas with scant state presence gives rise to a process of radicalization among local elites. There are multiple factors that explain the emergence of paramilitary groups. Aside from the post Cold War international context, there were national factors like a shift in its focus away from security matters between 1989 and 1993, and presidential policies between 1968 and 1993, that planted the seeds of leftist radicalism in a context of id modernization

La educación secundaria y sus dos dimensiones, efectos del barrio y del colegio sobre los resultados saber 11.

Resumen: Este trabajo estudia los resultados en matemáticas y lenguaje de 32000 estudiantes en la prueba saber 11 del 2008, de la ciudad de Bogotá. Este análisis reconoce que los individuos se encuentran contenidos en barrios y colegios, pero no todos los individuos del mismo barrio asisten a la misma escuela y viceversa. Con el fin de modelar esta estructura de datos se utilizan varios modelos econométricos, incluyendo una regresión jerárquica multinivel de efectos cruzados. Nuestro objetivo central es identificar en qué medida y que condiciones del barrio y del colegio se correlacionan con los resultados educacionales de la población objetivo y cuáles características de los barrios y de los colegios están más asociadas al resultado en las pruebas. Usamos datos de la prueba saber 11, del censo de colegios c600, del censo poblacional del 2005 y de la policía metropolitana de Bogotá. Nuestras estimaciones muestran que tanto el barrio como el colegio están correlacionados con los resultados en las pruebas; pero el efecto del colegio parece ser mucho más fuerte que el del barrio. Las características del colegio que están más asociadas con el resultado en las pruebas son la educación de los profesores, la jornada, el valor de la pensión, y el contexto socio económico del colegio. Las características de los barrios más asociadas con el resultado en las pruebas son, la presencia de universitarios en la UPZ, un clúster de altos niveles de educación y nivel de crimen en el barrio que se correlaciona negativamente. Los resultados anteriores fueron hallados teniendo en cuenta controles familiares y personales.