Studies on Fluorescence Efficiency and Photodegradation of Rhodamine 6G Doped PMMA Using a Dual Beam Thermal Lens Technique

In this paper we report the use of the dual beam thermal lens technique as a quantitative method to determine absolute fluorescence quantum efficiency and concentration quenching of fluorescence emission from rhodamine 6G doped Poly(methyl methacrylate) (PMMA), prepared with different concentrations of the dye. A comparison of the present data with that reported in the literature indicates that the observed variation of fluorescence quantum yield with respect to the dye concentration follows a similar profile as in the earlier reported observations on rhodamine 6G in solution. The photodegradation of the dye molecules under cw laser excitation is also studied using the present method.

Teams make it work : How team work engagement mediates between social resources and performance in teams

Resumen tomado de la publicaci??n

Oral Presentations: Preparation and Performance

A short lecture on presentation skills in an academic environment

Leadership and performance in multicultural business environments a qualitative study in German-Colombian teams

Multicultural leadership is a topic a great interest in nowadays globalized work environment. Colombia emerges as an attractive marketplace with appealing business opportunities, especially for German enterprises. After presenting Colombia’s current political, social and economic situation, the thesis elaborates the complex subject of cultural differences while focusing on the peculiarities of German and Colombian national cultures. The resulting implications for a team’s collaboration and leader effectiveness are theoretically supported with reference to the landmark studies of Hofstede and GLOBE. By utilizing semi-structured interview techniques, a qualitative research enriches the previous findings and gives an all-encompassing insight in German-Colombian teamwork. The investigation identifies distinctive behavioral patterns and relations, which imply challenges and factors of success for multicultural team leaders. Finally, a categorical analysis examines the influence of cultural traits on team performance and evaluates the effectiveness of the applied leadership style.

Prediction of human adaptation and performance in underwater environments

Resumen tomado de la publicaci??n

Importance of self-efficacy in psychoendocrine responses to competition and performance in women

Resumen tomado de la publicaci??n

Social networks and performance in knowledge creation. An application and a methodological proposal

El objetivo de esta tesis es predecir el rendimiento de los estudiantes de doctorado en la Universidad de Girona según características personales (background), actitudinales y de redes sociales de los estudiantes. La población estudiada son estudiantes de tercer y cuarto curso de doctorado y sus directores de tesis doctoral. Para obtener los datos se ha diseño un cuestionario web especificando sus ventajas y teniendo en cuenta algunos problemas tradicionales de no cobertura o no respuesta. El cuestionario web se hizo debido a la complejidad que comportan de las preguntas de red social. El cuestionario electrónico permite, mediante una serie de instrucciones, reducir el tiempo para responder y hacerlo menos cargado. Este cuestionario web, además es auto administrado, lo cual nos permite, según la literatura, unas respuestas mas honestas que cuestionario con encuestador. Se analiza la calidad de las preguntas de red social en cuestionario web para datos egocéntricos. Para eso se calcula la fiabilidad y la validez de este tipo de preguntas, por primera vez a través del modelo Multirasgo Multimétodo (Multitrait Multimethod). Al ser datos egocéntricos, se pueden considerar jerárquicos, y por primera vez se una un modelo Multirasgo Multimétodo Multinivel (multilevel Multitrait Multimethod). Las la fiabilidad y validez se pueden obtener a nivel individual (within group component) o a nivel de grupo (between group component) y se usan para llevar a cabo un meta-análisis con otras universidades europeas para analizar ciertas características de diseño del cuestionario. Estas características analizan si para preguntas de red social hechas en cuestionarios web son más fiables y validas hechas "by questions" o "by alters", si son presentes todas las etiquetas de frecuencia para los ítems o solo la del inicio y final, o si es mejor que el diseño del cuestionario esté en con color o blanco y negro. También se analiza la calidad de la red social en conjunto, en este caso específico son los grupos de investigación de la universidad. Se tratan los problemas de los datos ausentes en las redes completas. Se propone una nueva alternativa a la solución típica de la red egocéntrica o los respondientes proxies. Esta nueva alternativa la hemos nombrado "Nosduocentered Network" (red Nosduocentrada), se basa en dos actores centrales en una red. Estimando modelos de regresión, esta "Nosduocentered network" tiene mas poder predictivo para el rendimiento de los estudiantes de doctorado que la red egocéntrica. Además se corrigen las correlaciones de las variables actitudinales por atenuación debido al pequeño tamaño muestral. Finalmente, se hacen regresiones de los tres tipos de variables (background, actitudinales y de red social) y luego se combinan para analizar cual para predice mejor el rendimiento (según publicaciones académicas) de los estudiantes de doctorado. Los resultados nos llevan a predecir el rendimiento académico de los estudiantes de doctorado depende de variables personales (background) i actitudinales. Asimismo, se comparan los resultados obtenidos con otros estudios publicados.

Efficiency and social inclusion: implications for the museum profession

In the late 1980s Stephen Weil (1990) raised the question of the extent to which museum work could be considered a profession, the extent to which it had been professionalized, and in what ways this professionalization was facilitated or impeded by the changing circumstances of museum work, its organizational and governance context and its already multiplying roles vis-à-vis public culture and society at large. Although Weil‘s thoughts were situated in the American museum context of the mid-1980s, many of his thoughts apply to contexts beyond the US, and some of the questions he raised about the potential for professionalising museum work still resonate with the current situation of museum work. This paper tries to pose and approach a host of questions that, whilst in the main echoing Stephen Weil‘s mid-1980s reflections, are reconfigured in light of some sweeping changes in the nature of museum work, its mode of governance and its governing norms and values.

Response to Anwar Tlili‘s paper -Efficiency and social inclusion: implications for the museum profession

I have been asked to respond to Anwar Tlili‘s paper, and I propose to do this in four steps. I will follow Anwar‘s line of arguments closely. I will be dealing in turn withStep no. 1: Profession and ProfessionalizationStep no. 2: Social InclusionStep no. 3: ManagerialismStep no. 4: Museum Education and Training

Effect of acyl chain length on transfection efficiency and toxicity of polyethylenimine

Polyethylenimine (PEI) is an efficient nonviral gene delivery vector because of its high buffering capacity and DNA condensation ability. In our study, the amino groups on the polymeric backbone were acylated using acetic or propionic anhydride to alter the protonation behaviour and the hydrophilic/hydrophobic balance of the polymer. The concentration of acylated primary amines was determined using trinitrobenzene sulphonic acid assay. Results showed that our modified polymers had lower buffering capacities in solutions compared to PEI. The polymers were complexed with plasmid encoding enhanced green fluorescent protein at three different ratios (1:1, 1:2 and 1:10 w/w DNA to polymer) to form polyplexes and their toxicities and transfection efficiencies were evaluated in HEK 293 cells. Acylation reduced the number of primary amines on the polymer and the surface charge, improving haemocompatibility and reducing cytotoxicity. The reduction in the concentration of amino groups helped to optimise DNA compaction and facilitated polyplex dissociation in the cell, which increased transfection efficiency of the modified polymers compared to the parent polymer. Polymers with buffering capacities greater than 50% and less than 80% relative to PEI, showed higher transfection efficiencies than PEI. The propionic anhydride modified polymers had appropriate interactions with DNA which provided both DNA compaction and polyplex dissociation. These systems interacted better with the cell membrane because of their slightly higher lipophilicity and formed polyplexes which were less cytotoxic than polyplexes of acetic anhydride modified polymers. Among the vectors tested, 1:0.3 mol/mol PEI:propionic anhydride in a 1:2 w/w DNA:polymer composition provided the best transfection system with improved transfection efficiency and reduced cytotoxicity.

Revised IR spectrum, radiative efficiency and global warming potential of nitrogen trifluoride

Nitrogen trifluoride (NF3) is an industrial gas used in the semiconductor industry as a plasma etchant and chamber cleaning gas. NF3 is an alternative to other potent greenhouse gases and its usage has increased markedly over the last decade. In recognition of its increased relevance and to aid planning of future usage we report an updated radiative efficiency and global warming potentials for NF3. Laboratory measurements give an integrated absorption cross section of 7.04 x 10(-17) cm(2) molecule(-1) cm(-1) over the spectral region 200 2000 cm(-1). The radiative efficiency is calculated to be 0.21 Wm(-2) ppbv(-1) and the 100 year GWP, relative to carbon dioxide, is 17200. These values are approximately 60% higher than previously published estimates, primarily reflecting the higher infrared absorption cross-sections reported here.

Does the regional nature of multinationals affect the multinationality and performance relationship?

The traditional independent variable in the multinationality and performance literature is the ratio of foreign (F) to total (T) sales, (F/T). This can now be supplemented by a new regional variable, the ratio of regional (R) to total (T) sales, i.e. (R/T). Data are presented on both (F/T) and (R/T) for both sales and assets for a 5-year period, 2001–2005. New tests are reported on (R/T) as it affects a financial measure of performance, the Tobin's Q. Implications are drawn for future research on the S-curve relationship between multinationality and performance in the light of this regional phenomenon.