917 resultados para NETWORK ANALYSIS
Resumo:
The goal of this article was to study teachers' professional development related to web-based learning in the context of the teacher community. The object was to learn in what kind of networks teachers share the knowledge of web-based learning and what are the factors in the community that support or challenge teachers professional development of web-based learning. The findings of the study revealed that there are teachers who are especially active, called the central actors in this study, in the teacher community who collaborate and share knowledge of web-based learning. These central actors share both technical and pedagogical knowledge of web-based learning in networks that include both internal and external relations in the community and involve people, artefacts and a variety of media. Furthermore, the central actors appear to bridge different fields of teaching expertise in their community. According to the central actors' experiences the important factors that support teachers' professional development of web-based learning in the community are; the possibility to learn from colleagues and from everyday working practices, an emotionally safe atmosphere, the leader's personal support and community-level commitment. Also, the flexibility in work planning, challenging pupils, shared lessons with colleagues, training events in an authentic work environment and colleagues' professionalism are considered meaningful for professional development. As challenges, the knowledge sharing of web-based learning in the community needs mutual interests, transactive memory, time and facilities, peer support, a safe atmosphere and meaningful pedagogical practices. On the basis of the findings of the study it is suggested that by intensive collaboration related to web-based learning it may be possible to break the boundaries of individual teachership and create such sociocultural activities which support collaborative professional development in the teacher community. Teachers' in-service training programs should be more sensitive to the culture of teacher communities and teachers' reciprocal relations. Further, teacher trainers should design teachers' in-service training of web-based learning in co-evolution with supporting networks which include the media and artefacts as well as people.
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Although reciprocity is fundamental to all social orders, management research offers few reviews of the concept’s theoretical origins and current applications. To help bridge this gap, we elucidate the dominant understandings of reciprocity, ask which areas of research emerge from them, and explore how they interconnect. Our bibliometric methodology detects four clusters of management research on reciprocity. Across these clusters, authors subscribe mainly to substantialist ontology, marginalize morally oriented motives consistent with relational ontology, and largely assume that benefit-oriented motives underlie reciprocity. We outline the advantages of a moral-oriented relationalist concept of reciprocity and discuss potential areas for its development in management research.
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Independent regulatory agencies (IRAs) were created in various sectors and on different governmental levels to implement liberalization policies. This paper investigates the link between IRAs' independence, which is said to promote regulatory credibility and the use of technical expertise, and their accountability, which is related to the need for controlling and legitimizing independent regulators. The literature on the regulatory state anticipates a positive relation between the independence and accountability of IRAs, but systematic empirical evidence is still lacking. To tackle this question, this paper measures and compares the independence and the accountability of IRAs in three differentially liberalized sectors in Switzerland (telecommunications, electricity and railways). With the application of Social Network Analysis, this piece of research shows that IRAs can be de facto independent and accountable at the same time, but the two features do not necessarily co-evolve in the same direction.
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BACKGROUND Interferon-α (IFN-α) treatment suppresses HIV-1 viremia and reduces the size of the HIV-1 latent reservoir. Therefore, investigation of the molecular and immunologic effects of IFN-α may provide insights that contribute to the development of novel prophylactic, therapeutic and curative strategies for HIV-1 infection. In this study, we hypothesized that microRNAs (miRNAs) contribute to the IFN-α-mediated suppression of HIV-1. To inform the development of novel miRNA-based antiretroviral strategies, we investigated the effects of exogenous IFN-α treatment on global miRNA expression profile, HIV-1 viremia, and potential regulatory networks between miRNAs and cell-intrinsic anti-HIV-1 host factors in vivo. METHODS Global miRNA expression was examined in longitudinal PBMC samples obtained from seven HIV/HCV-coinfected, antiretroviral therapy-naïve individuals before, during, and after pegylated interferon-α/ribavirin therapy (IFN-α/RBV). We implemented novel hybrid computational-empirical approaches to characterize regulatory networks between miRNAs and anti-HIV-1 host restriction factors. RESULTS miR-422a was the only miRNA significantly modulated by IFN-α/RBV in vivo (p<0.0001, paired t test; FDR<0.037). Our interactome mapping revealed extensive regulatory involvement of miR-422a in p53-dependent apoptotic and pyroptotic pathways. Based on sequence homology and inverse expression relationships, 29 unique miRNAs may regulate anti-HIV-1 restriction factor expression in vivo. CONCLUSIONS The specific reduction of miR-422a is associated with exogenous IFN-α treatment, and likely contributes to the IFN-α suppression of HIV-1 through the enhancement of anti-HIV-1 restriction factor expression and regulation of genes involved in programmed cell death. Moreover, our regulatory network analysis presents additional candidate miRNAs that may be targeted to enhance anti-HIV-1 restriction factor expression in vivo.
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Excavations of Neolithic (4000 – 3500 BC) and Late Bronze Age (1200 – 800 BC) wetland sites on the northern Alpine periphery have produced astonishing and detailed information about the life and human environment of prehistoric societies. It is even possible to reconstruct settlement histories and settlement dynamics, which suggest a high degree of mobility during the Neolithic. Archaeological finds—such as pottery—show local typological developments in addition to foreign influences. Furthermore, exogenous lithic forms indicate far reaching interaction. Many hundreds of bronze artefacts are recorded from the Late Bronze Age settlements, demonstrating that some wetland sites were centres of bronzework production. Exogenous forms of bronzework are relatively rare in the wetland settlements during the Late Bronze Age. However, the products produced in the lake-settlements can be found widely across central Europe, indicating their continued involvement in interregional exchange partnerships. Potential motivations and dynamics of the relationships between sites and other regions of Europe will be detailed using case studies focussing on the settlements Seedorf Lobsigensee (BE), Concise (VD), and Sutz-Lattrigen Hauptstation innen (BE), and an initial assessment of intra-site connectivity through Network Analysis of sites within the region of Lake Neuchâtel, Lake Biel, and Lake Murten.
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Policy brokers and policy entrepreneurs are assumed to have a decisive impact on policy outcomes. Their access to social and political resources is contingent on their influence on other agents. In social network analysis (SNA), entrepreneurs are often closely associated with brokers, because both are agents presumed to benefit from bridging structural holes; for example, gaining advantage through occupying a strategic position in relational space. Our aim here is twofold. First, to conceptually and operationally differentiate policy brokers from policy entrepreneurs premised on assumptions in the policy-process literature; and second, via SNA, to use the output of core algorithms in a cross-sectional analysis of political brokerage and political entrepreneurship. We attempt to simplify the use of graph algebra in answering questions relevant to policy analysis by placing each algorithm within its theoretical context. In the methodology employed, we first identify actors and graph their relations of influence within a specific policy event; then we select the most central actors; and compare their rank in a series of statistics that capture different aspects of their network advantage. We examine betweenness centrality, positive and negative Bonacich power, Burt’s effective size and constraint and honest brokerage as paradigmatic. We employ two case studies to demonstrate the advantages and limitations of each algorithm for differentiating between brokers and entrepreneurs: one on Swiss climate policy and one on EU competition and transport policy.
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Despite an increased scientific interest in the relatively new phenomenon of large-scale land acquisition (LSLA), data on processes on the local level remain sparse and superficial. However, knowledge about the concrete implementation of LSLA projects and the different impacts they have on the heterogeneous group of project affected people is indispensable for a deepened understanding of the phenomenon. In order to address this research gap, a team of two anthropologists and a human geographer conducted in-depth fieldwork on the LSLA project of Swiss based Addax Bioenergy in Sierra Leone. After the devastating civil war, the Sierra Leonean government created favourable conditions for foreign investors willing to lease large areas of land and to bring “development” to the country. Being one of the numerous investing companies, Addax Bioenergy has leased 57’000 hectares of land to develop a sugarcane plantation and an ethanol factory to produce biofuel for the export to the European market. Based on participatory observation, qualitative interview techniques and a network analysis, the research team aimed a) at identifying the different actors that were necessary for the implementation of this project on a vertical level and b) exploring various impacts of the project in the local context of two villages on a horizontal level. The network analysis reveals a complex pattern of companies, institutions, nongovernmental organisations and prominent personalities acting within a shifting technological and discursive framework linking global scales to a unique local context. Findings from the latter indicate that affected people initially welcomed the project but now remain frustrated since many promises and expectations have not been fulfilled. Although some local people are able to benefit from the project, the loss of natural resources that comes along with the land lease affects livelihoods of vulnerable groups – especially women and land users – considerably. However, this research doesn’t only disclose impacts on local people’s previous lives but also addresses strategies they adopt in the newly created situation that has opened up alternative spaces for renegotiations of power and legitimatisation. Therewith, this explorative study reveals new aspects of LSLA that have not been considered adequately by the investing company nor by the general academic discourse on LSLA.
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Seizure freedom in patients suffering from pharmacoresistant epilepsies is still not achieved in 20–30% of all cases. Hence, current therapies need to be improved, based on a more complete understanding of ictogenesis. In this respect, the analysis of functional networks derived from intracranial electroencephalographic (iEEG) data has recently become a standard tool. Functional networks however are purely descriptive models and thus are conceptually unable to predict fundamental features of iEEG time-series, e.g., in the context of therapeutical brain stimulation. In this paper we present some first steps towards overcoming the limitations of functional network analysis, by showing that its results are implied by a simple predictive model of time-sliced iEEG time-series. More specifically, we learn distinct graphical models (so called Chow–Liu (CL) trees) as models for the spatial dependencies between iEEG signals. Bayesian inference is then applied to the CL trees, allowing for an analytic derivation/prediction of functional networks, based on thresholding of the absolute value Pearson correlation coefficient (CC) matrix. Using various measures, the thus obtained networks are then compared to those which were derived in the classical way from the empirical CC-matrix. In the high threshold limit we find (a) an excellent agreement between the two networks and (b) key features of periictal networks as they have previously been reported in the literature. Apart from functional networks, both matrices are also compared element-wise, showing that the CL approach leads to a sparse representation, by setting small correlations to values close to zero while preserving the larger ones. Overall, this paper shows the validity of CL-trees as simple, spatially predictive models for periictal iEEG data. Moreover, we suggest straightforward generalizations of the CL-approach for modeling also the temporal features of iEEG signals.
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Mechanisms that allow pathogens to colonize the host are not the product of isolated genes, but instead emerge from the concerted operation of regulatory networks. Therefore, identifying components and the systemic behavior of networks is necessary to a better understanding of gene regulation and pathogenesis. To this end, I have developed systems biology approaches to study transcriptional and post-transcriptional gene regulation in bacteria, with an emphasis in the human pathogen Mycobacterium tuberculosis (Mtb). First, I developed a network response method to identify parts of the Mtb global transcriptional regulatory network utilized by the pathogen to counteract phagosomal stresses and survive within resting macrophages. As a result, the method unveiled transcriptional regulators and associated regulons utilized by Mtb to establish a successful infection of macrophages throughout the first 14 days of infection. Additionally, this network-based analysis identified the production of Fe-S proteins coupled to lipid metabolism through the alkane hydroxylase complex as a possible strategy employed by Mtb to survive in the host. Second, I developed a network inference method to infer the small non-coding RNA (sRNA) regulatory network in Mtb. The method identifies sRNA-mRNA interactions by integrating a priori knowledge of possible binding sites with structure-driven identification of binding sites. The reconstructed network was useful to predict functional roles for the multitude of sRNAs recently discovered in the pathogen, being that several sRNAs were postulated to be involved in virulence-related processes. Finally, I applied a combined experimental and computational approach to study post-transcriptional repression mediated by small non-coding RNAs in bacteria. Specifically, a probabilistic ranking methodology termed rank-conciliation was developed to infer sRNA-mRNA interactions based on multiple types of data. The method was shown to improve target prediction in Escherichia coli, and therefore is useful to prioritize candidate targets for experimental validation.
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Nuestro trabajo tiene como objetivo aplicar conceptos de la teoría de los sistemas complejos y herramientas del análisis de redes sociales para describir y analizar el surgimiento y la evolución de una red social conformada por científicos, docentes, graduados y funcionarios públicos de diferentes organismos científicos y académicos, que crearon y participaron de un equipo multidisciplinario que elaboró un informe sobre un proyecto de ley de Ordenamiento Territorial y Usos del Suelo de la provincia de Mendoza en el año 2006. Para la compresión de la evolución del proceso de elaboración del proyecto de ley de ordenamiento territorial y de usos del suelo, organizaremos la estructura del trabajo de la siguiente manera: - Primero aplicaremos aspectos teóricos y metodológicos, basados en la sistematización realizada por Rolando García en su libro “Sistemas Complejos. Conceptos, método y fundamentación epistemológica de la investigación interdisciplinaria", para realizar el recorte del sistema objeto de estudio. - En segundo lugar utilizaremos la Teoría de Análisis de Redes Sociales para describir la composición y estructura del sistema (nodos y vínculos) en cada momento. La estructura del sistema en cada momento significativo será graficada por medio el Software Ucinet 6 y NetDraw. - Por último, haremos referencia a las dificultades que tuvo el proceso desde el punto de vista de las condicionalidades que generaban los modelos mentales que portaban los participantes.
Resumo:
En este trabajo analizaremos los lazos sociales mantenidos y generados por los inmigrantes gallegos en el Buenos Aires tardo colonial, con otros familiares y paisanos instalados en la capital virreinal o en la tierra natal. Tomaremos en consideración los aportes del Análisis de Redes a los estudios migratorios y a partir de ello identificaremos las redes étnicas y los mecanismos sociales que las activaron. Nos basaremos en un conjunto variado de fuentes (las actas matrimoniales, las sucesiones testamentarias, los padrones de habitantes y expedientes varios localizados en el Archivo General de la Nación Argentina) que nos permitirán examinar las diferentes vías (el ejercicio comercial, los matrimonios, el temprano asociacionismo, las disposiciones testamentarias, entre otras) a través de las cuales los inmigrantes establecieron los contactos sociales en cuestión. De este modo, constataremos el componente afectivo e identificatorio que pudo orientar los lazos étnicos y su importante funcionalidad instrumental, en un contexto donde el inmigrante necesitaba garantizar su integración en la sociedad de acogida. El estudio también pondrá de manifiesto que, sin llegar a constituirse en un “grupo cerrado", los oriundos de Galicia reforzaron sus vínculos entre sí, cuando fue posible.
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El artículo estudia el surgimiento y la clausura del Ateneo de Cultura Popular de Tandil en el clima mundial de la lucha antifascista. Su propósito principal es identificar los mecanismos de circulación de ideas entre un centro cultural y su periferia y, a la vez, observar el contexto de recepción de ellas. Partiendo de los supuestos teóricos del social network analysis, se propone analizar el tejido de relaciones personales activado en la dinámica del centro cultural para explicar el motivo de su clausura. Así, presenta las dimensiones estructurales e interaccionales de la red social en la que los actores se hallan insertos. Finalmente, el artículo puede ser considerado un ejercicio intelectual para entender espacios sociales de práctica cultural en los que no domina la actividad profesionalizada.
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Con el objetivo de determinar el grupo de publicaciones nucleares a considerar en el desarrollo de la colección de la Biblioteca del IAR, se realiza un estudio bibliométrico de la producción y del consumo de literatura científica de los investigadores de la institución a la que la biblioteca pertenece. A partir del análisis de referencias de los trabajos publicados por los investigadores se determinan la obsolescencia y la utilidad de la literatura consultada. Mediante la extracción de palabras clave y de los autores se determinan también los frentes de investigación del instituto y los grupos de investigadores que trabajan en esos frentes, aplicando los métodos de análisis de co-ocurrencia de palabras, coautorías y análisis de redes sociales. Los resultados dan cuenta de una baja obsolescencia para la literatura consultada, de una elevada preferencia para consultar y publicar en dos o tres títulos de publicaciones periódicas de la disciplina, y demuestran finalmente la existencia de dos frentes de investigación dentro de la institución
Resumo:
En este trabajo abordamos el análisis de experiencias exiliares de trabajadores chilenos que se radicaron en el Noreste de la Provincia de Chubut, en Patagonia Argentina, después de producido el golpe de estado contra el presidente democrático Salvador Allende Gossens, en Septiembre de 1973. Cuando revisé la factibilidad de la investigación, y en mérito a los escasos repositorios documentales, decidí, dando continuidad a indagaciones previas, trabajar con historia oral. Esta metodología o práctica, involucra una dimensión personal, subjetiva y afectiva, que supone una constante relación entre los sujetos que participan, lo que implica una cualitativa diferencia en relación a las fuentes más tradicionales. No minimizo el valor de la estadística, pero hago una opción por nombrar y conocer a quienes han compartido con nosotros vivencias y experiencias, explicitando nuestra inscripción en la construcción de la información documental, no objetivándonos. El trabajo desarrollado se halla en la encrucijada entre la historia del pasado reciente y la memoria; con una perspectiva "desde abajo", buscando conjugar la no uniformidad de la experiencia humana, con la pretensión de generalidad y explicación de la ciencia social. Las narraciones o testimonios obtenidos las he revisado, procurando develar las representaciones que subyacen, y comprendiendo el modo en que actuaron. Las memorias tienen un carácter subjetivo y en permanente transformación, lo que en cierto sentido puede singularizarlas, pero como historiadores debemos inscribirlas en un contexto histórico global, para procurar esclarecer las causas, las condiciones, y las estructuras, aportando a una historia total. Hemos rescatado prácticas, percepciones, y discursos; develando la importancia del trabajo como factor organizador y estabilizador, al dotar a estos sujetos, de un sitio en la sociedad receptora, y permitiéndoles "ir desarmando sus valijas", es decir, ir superando la transitoriedad. Al caracterizar al exilio chileno, en el contexto internacional y local; y atendiendo a las escasas producciones que dan cuenta del universo obrero en estas experiencias traumáticas, han sido evidentes los límites que supone una estricta separación entre exilio, y migración económica o política; ya que dicha conceptualización encierra una mirada que invisibiliza derroteros que en principio, o superficialmente, pueden ser leídos como poco organizados. La aplicación del análisis de red, por cierto contribuyó a hacerlos visibles, transformándolos en actores racionales, con objetivos que se movilizaron a partir de los recursos de que dispusieron; tratando de superar el paradigma que hacía de ellos seres desesperados: fueron mujeres y hombres que eligieron un destino posible, siempre atendiendo al doble carácter de la experiencia en que estuvieron inmersos: la salida de su país por un lado los liberó, pero también los privó; asociando indisolublemente sentimientos de dolor por el desprendimiento de lo propio -de los afectos personales y colectivos-, agravados por los efectos de la derrota y la incertidumbre. Son sujetos que pusieron su identidad en riesgo. Pretendemos lograr que esta investigación, no sea sólo un estudio de caso, sino que pueda inscribirse a partir de su especificidad, en tanto exilio obrero, en una perspectiva comparativa, superando una definición espacial específica, en el Nor Este de Chubut.