Finite-size effects in intracellular microrheology

We propose a model to explain finite-size effects in intracellular microrheology observed in experiments. The constrained dynamics of the particles in the intracellular medium, treated as a viscoelastic medium, is described by means of a diffusion equation in which interactions of the particles with the cytoskeleton are modelled by a harmonic force. The model reproduces the observed power-law behavior of the mean-square displacement in which the exponent depends on the ratio between particle-to-cytoskeleton-network sizes.Comment: 6 pages 2 figures. To appear in the Journal of Chemical Physic

Liderança critica aplicada através da lens latinas: um abordagem alternativo do liderança educacional

The aims and objectives of this research were to investigate and better understand ways in which race and gender play out as differences of significant consequence in applied leadership practice. Utilizing qualitative case study methodology coupled with counter-story, a critical race theory approach, the authors analyze data on two Mexican descent educational leaders in the US: one Latino K-6 principal and one Chicana university Dean. Findings indicate evidence supporting positive identity leadership traits as practiced through raced and gender lenses, resulting in effective socially just and equitable leadership outcomes for the participants in the study. These findings are new and particularly relevant as demographic shifts in the US and the world include high numbers of Latino/a and Mexican descent individuals. The strategies employed by participants suggest subaltern ways of educational leadership not previously considered in research and literature. The authors discuss evidence of characteristics supporting applied critical leadership (ACL), an emerging leadership theory, in the leadership practices of the participants. Finally, mainstream implications and guidelines are provided for application in multiple educational leadership contextsEl propósito y objetivos de esta investigación fueron investigar y comprender mejor las formas en las que la raza y el género generan importantes consecuencias en la práctica del liderazgo aplicado. Se realiza un estudio de caso cualitativo con contra-historia con un enfoque teórico-crítico sobre raza,. Los autores analizan datos sobre dos líderes educativos de ascendencia mexicana en los EE.UU.: uno director de una escuela K-6 latina y el otro, director de una universidad chicana. Los hallazgos evidencian rasgos de identidad positiva de los líderes que permite la puesta en práctica de un liderazgo equitativo y socialmente justo entre los participantes del estudio. Estos hallazgos son novedosos y especialmente relevantes en EEUU y en el resto de países donde viven un alto número de descendientes de latinos y mexicanos. Las estrategias empleadas por los participantes sugieren alternar formas de liderazgo no consideradas ni en la investigación ni en la literatura. Los autores discuten las evidencias encontradas que definen la teoría emergente del liderazgo crítico aplicado (ACL). Por último, se aportan directrices para su aplicación en diferentes contextosA finalidade e objetivos desta pesquisa foram investigar e entender melhor as maneiras em que raça e gênero têm implicações importantes para a prática da liderança aplicada. Foi feito um estudo de caso qualitativo com contra-história é com uma abordagem teórica e crítica à raça e gênero. Os autores analisaram dados de dois líderes educacionais de ascendência mexicana em EUA: um director de um K-6 escola latina e no outro, diretor do faculdade chicana. Os resultados mostram traços de identidade positiva de líderes, que permite a implementação de uma liderança justa e socialmente justa entre os participantes do estudo. Estes resultados são novos e particularmente relevante em os EUA e outros países onde vivem um elevado número de descendentes de latinos e mexicanos. As estratégias empregadas pelos participantes sugerem formas alternativas de liderança não considerado ou pesquisa ou literatura. Os autores discutem as evidências encontradas que definem a teoria emergente de liderança crítica aplicada (ACL). Finalmente, orientações para a aplicação em diferentes contextos são fornecido

Transformative Critical Leadership in Action: Re-visioning an Equity Agenda to Address the Community College Achievement Gap

This conceptual article summarizes the call for transformative critical leadership in education and provides an overview of the equity agenda in response to the identified academic achievement gap in community colleges nationwide. It offers educational leaders in higher education applied and feasible strategies for increasing critical communication with educators, community members, and stakeholders interested in re-visioning core tenants of equity agendas at the community college level. The chapter also suggests the consideration of critical leadership as an emergent type of transformative leadership practice involving the facilitation of crucial conversations to incite change as well as policy implications

Analytic and bootstrap approximations of prediction errors under a multivariate fay-herriot model

A Multivariate Fay-Herriot model is used to aid the prediction of small area parameters of dependent variables with sample data aggregated to area level. The empirical best linear unbiased predictor of the parameter vector is used, and an approximation of the elements of the mean cross product error matrix is obtained by an extension of the results of Prasad and Rao (1990) to the multiparameter case. Three different bootstrap approximations of those elements are introduced, and a simulation study is developed in order to compare the efficiency of all presented approximations, including a comparison under lack of normality. Further, the number of replications needed for the bootstrap procedures to get stabilized are studied

Indigenous Urban School Leadership: A Critical Cross-Cultural Comparative Analysis of Educational Leaders in New Zealand and the United States

This qualitative inquiry compares the practice of one Māori primary school leader of urban education for indigenous multicultural multilingual learners in New Zealand (NZ), to research on the practices of nine educational leaders of colour in the United States (US). This study identifies and compares leadership practices for leaders struggling with ways to positively impact learner outcomes in similar settings (e.g., UK, Canada). From a critical comparative perspective, this school principal shares her leadership practice and lessons learned to inform leadership practice in similarly multifaceted urban settings. This research is undertaken by a collaborative cross-cultural team of educational leaders and scholars from the US and NZ, from the local university and urban primary school. The research team comprises multiple perspectives, the basis for global comparative discourse on school leadership. This contribution offers a cross-cultural model, framework, and way of doing educational research to increase understanding of leadership in different societies

Intercambios comerciales internos en el Alto Perú colonial tardío.

Sin resume

Phase-transfer function of the human eye and its influence on point-spread function and wave aberration.

The bidimensional phase-transfer function (PTF) of the human eye has been computed from aerial retinal images of a point test. These images were previously determined by using a recently developed hybrid optical-digital method. Actual PTF data have been obtained directly without linear variations with spatial frequency and have shown great variations among individual subjects. The influence of the PTF on the determination of the point-spread function and the wave-aberration function for emmetropized and slightly astigmatic subjects has been also evaluated. Finally, the effect of pupil size on the PTF was determined by computing these functions from the wave aberration. These results allow us to give a more thorough description of the optical image quality of the human eye and can be used as actual data in subsequent psychophysical studies.The authors thank M. Nieto-Vesperinas for his critical reading of the manuscript. This research was supported by the Comision Asesora de Investigaci6n Cientifica y T6cnica (grant 2520/83), Ministerio de Educaci6n y Ciencia, Spain.Peer Reviewe