1,065 research outputs found
Dating the cyanobacterial ancestor of the chloroplast
Cyanobacteria have played a pivotal role in the history of life on Earth being the first organism to carry out oxygenic photosynthesis, which changed atmospheric chemistry and allowed the evolution of Eukarya. Chloroplasts are the cellular organelles of photoautotrophic eukaryotes in which photosynthesis is conducted. Although the initial suggestion from Mereschkowsky (1905) that cyanobacteria are the ancestors of chloroplasts was greeted with skepticism, the idea is now widely accepted. Here we attempt to resolve and date the cyanobacterial ancestry of the chloroplast using phylogenetic analysis and molecular clocks, because until now, the long-standing question of, from which, among the vast diversity of cyanobacteria, did chloroplasts evolve, has not been resolved. We found that chloroplasts form a monophyletic lineage, are most closely related to subsection I, N2-fixing unicellular cyanobacteria (Order Chroococcales), and heterocyst-forming Order Nostocales cyanobacteria are their sister group. The appearance of Nostocales and of Chroococcales occurred during the Paleoproterozoic, and chloroplasts appeared in the mid-Proterozoic. The capability of N2-fixation in cyanobacteria appeared once during the late Archaen and early Proterozoic eons. Furthermore, we found that oxygen-evolving cyanobacteria could have appeared in the Archean. Our results suggest that a free-living cyanobacterium with the capacity to store starch via oxygenic CO2 fixation, and to fix atmospheric N2, would be a very important intracellular acquisition, which, as can be recounted today from several lines of evidence, would have become the chloroplast by endosymbiosis
La doble trans-posición: de la Literatura a la Antropología y viceversa. Presentación del volumen monográfico: Antropología y Literatura
Este texto introduce y presenta los artículos del monográfico sobre Antropología y Literatura que integran el volumen 17 de la Revista de Antropología Social. Se plantea, en primer lugar, el inestable equilibrio entre Antropología y Literatura, etnografía y ficción, abriendo el análisis hacia el cambio de paradigma teórico que cimentó las condiciones para la innovación en los textos etnográficos. Se detiene asimismo en la doxa que se impone en el ámbito antropológico, donde la polisemia del concepto ficción es problemática. Y se pretende también proporcionar al lector claves para leer y reflexionar sobre Antropología y Literatura como disciplinas refractarias, cuya conciencia crítica de oposición y, al mismo tiempo, de dependencia surge en los años de la posmodernidad y continúa hasta el presente con variaciones y desviaciones múltiples. En suma, se introduce al lector en una obra ecléctica e interseccional con planteamientos teóricos y estudio de casos originales.This presentation introduces the articles that constitute the monographic on Anthropology and Literature in the seventeen volume of the Revista de Antropología Social. I argue, first, about the instable equilibrium between ethnography and fiction and I open the analysis to the change of the paradigm that build the conditions for innovation in the ethnography texts. This article also deals with the doxa that impose itself in the anthropological field where the polisemia of the concept of fiction is problematic. I intent as well to bring to the reader some key in order to read and think about Anthropology and Literature as refracted disciplines, which critic conscience of opposition and dependence at the same time, emerges in the years of posmodernity and continues through the present with variations and multiples deviations. In short, this presentation introduces reader to an eclectic and intersectional work, with theoretical arguments and original case studies
Market power and risk taking behavior of banks
We consider a monopolistically competitive banking sector in order to analyze the effects of market concentration on the risk-taking behavior of banks. We show that, under full deposit insurance, a higher level of competition induces banks to invest in a risky asset. When the market concentration is high banks tend to take less risk. We also show that maximum social welfare is achieved either through free entry or through entry restriction.
Periodismo social e inmigración en prensa : el caso Tarajal
Este Trabajo de Fin de Grado (TFG) pretende llevar a cabo un análisis, a partir de una
investigación documental, del tratamiento periodístico que le dan los principales medios
impresos españoles a nivel nacional y a nivel local, respectivamente, a las primeras
informaciones sobre los reprobables sucesos del 6 de febrero de 2014 en Ceuta, frontera
terrestre de la Unión Europea con África, cuando 15 inmigrantes perdieron la vida
intentando alcanzar a nado suelo español en aguas fronterizas de Ceuta, junto a la playa
ceutí del Tarajal. En estos hechos intervino la Guardia Civil española, que disparó
material antidisturbios contra civiles desarmados y en el mar, precisamente balas de
goma y gases lacrimógenos, y devolvió `en caliente´ a otros 23 inmigrantes a la playa
marroquí de Finideq. Casi dos años después de estos hechos y tras una investigación
judicial lenta, la magistrada que instruye este caso, María del Carmen Serván, decretó el
pasado jueves 15 de octubre de 2015 el sobreseimiento provisional de la causa. Además,
una reciente reforma en la Ley de Extranjería introducida mediante una enmienda en la
Ley de Seguridad Ciudadana, permite las devoluciones `en caliente´ y es cuestionada
dentro y fuera de España por constituir una violación de las normativas de Derechos
Humanos internacional y europea, incluyendo las disposiciones del Convenio Europeo
de Derechos Humanos y la Carta de Derechos Fundamentales de la Unión Europea. En
este tema están involucradas minorías víctimas de los hechos, por ello queremos
conocer si los medios de comunicación seleccionados han cumplido con los deberes de
un p eriodismo social , dando voz a los inmigrantes, denunciando injusticias y buscando
la verdad sin importar como ésta afecta al poder.
Este estudio, en definitiva, se centra en el primer mes de este acontecimiento, que
provocó un continuo flujo de informaciones y una reacción en cadena de versiones por
parte de responsables políticos y autoridades policiales para dirimir responsabilidades.
Sirviéndonos de la documentación y basándonos en un marco teórico sobre el
periodismo social y sus fuentes de información, hemos examinado y comparado con
una ficha de análisis el tratamiento de los dos medios impresos españoles con mayores
índices de difusión según la Oficina de Justificación de la Difusión (OJD): E l País , a
nivel nacional, y A BC de Sevilla a nivel local. Indicadores de calidad periodística como
la autoría o, sobre todo, las fuentes empleadas, entre otros, nos permiten conocer y
comparar el nivel periodístico de las informaciones y llegar a la conclusión de si se ha
llevado a cabo un p eriodismo social o, por el contrario, se ha hecho una mala praxis
periodística
El papel de las TIC en las universidades y empresas españolas
Más del 40% de las empresas del PTA son TIC cuya facturación supone la mitad de la generada en esta tecnopoli
El tiempo que no(s) sobra. Prejubilación, morfología urbana y actividad en el contexto avilesino
Since the 90’s pre-retirement among the textile, naval and miner industries have been very common. In Avilés the larger businesses, mostly the public ones, removed people between 52 and 60 years old from the labor market through the process of employment regulation. In this article I analyze how the morphology of the city of Avilés has changed due to the pre-retirement process. I also question the notion that the time of pre-retired people, characterized by different meanings and uses, is free and leisure time. Activities dedicated to others –and themselves– constitute that time which is embodied in the practice and in the subjectivity of the social agents as normal –normalized– time. It’s time distinct from leisure time.Desde los años noventa, han sido frecuentes las prejubilaciones dentro del sector siderometalúrgico, textil, naval y minero en España. A través de Expedientes de Regulación de Empleo, las empresas avilesinas desvincularon del mercado laboral a personas en edades comprendida entre los 52 y los 60 años. En este artículo se analiza, desde una aproximación etnográfica y social, cómo la morfología urbana ha cambiado a raíz de la prejubilación. Igualmente se cuestiona que el tiempo del prejubilado, caracerizado por significados y usos distintos dentro del colectivo, se defina como tiempo libre y de ocio. Las actividades dedicadas a los otros y a sí mismos van completando un tiempo que se incorpora en la subjetividad y a la práctica de los agentes como tiempo normal, –normalizado– y separado distintivamente del tiempo de ocio
The Island Heritage / El Patrimonio de la Isla
In 1926, Philip. J. Fisher published “The Island Heritage. Episodes from the Missionary History of Fernando Poo, West Africa. A Play for Young People”. This book has remained unknown until present. There is one copy at Archives and Special Collections, SOAS Library (London).
This play is of enormous interest not just for it has been mentioned above but also because: It is a vivid narration of the settlement of Protestant missionaries in Clarence, based on historical facts and personal experience collected first hand by Philip. J. Fisher as he interviewed some of the protagonists in the play. It is the first document with paragraph-length documented in Pichi, the Pidgin English (acrolect) originated in Clarence upon the arrival of liberated slaves who arrived with British colonizers in 1827, called Fernandinos (Sundiata 1975, 1996). It adopts the format of a play, something unusual until recent years, to the point that it can be considered the first work of this genre in the Equatoguinean colonial letters. The play tells the History of the Baptist Church work in Fernando Po and the missionaries’ vision to expand their proselytizing project in the mainland, which was achieved later on in Igumale, Nigeria. It is a piece of the British colonial archive, as we learn what was at stake on foreign policy between Spain - the official colonial power - and Great Britain regarding the African territories of Fernando Po (present day Bioko Island).
The translation from English to Spanish has been made by Susana Castillo-Rodríguez keeping in mind the historical context, the language change and the potential reader today. The ongoing second phase of this project is the English Critical Edition, provided as an annotated transcription here as the 2022 version, but the project is live and open for comments at the project\u27s main website: https://islandheritage.pubpub.org
Neighborhood And Environmental Factors And The Relationship To The Willingness To Use And Actual Uptake Of Pre-Exposure Prophylaxis (prep) Uptake, A Rapid Scoping Review
PrEP (Pre-Exposure Prophylaxis), which appeared on the market after FDA approval in 2012, is more than 90% effective against HIV transmission via sexual contact and more than 60% effective against HIV transmission via intravenous drug use. Current interventions focus on individual behavior or clinical guidelines, however, there has been little focus on the environmental factors affecting PrEP willingness and uptake. To investigate the relationship between neighborhood, environmental factors and PrEP willingness and uptake in the United States, a rapid scoping review was conducted with three electronic databases of articles (January 2012 – March 2020). Of the 2,016 citations screened, 11 articles were ultimately chosen for this review. Although PrEP willingness and uptake have been increasing overall, Black and Latinx people and those who live in rural areas, the Midwest, and the South significantly lag in this trend. Moreover, themes captured in the neighborhood and environmental variables were physician access, physician stigma, and resource access. Future policy recommendations will need to acknowledge the neighborhood and environmental factors that lead to disparities in HIV prevention
FPGA implementation and DPA resistance analysis of a lightweight HMAC construction based on photon hash family
Lightweight security is currently a challenge in the field of cryptography. Most of applications designed for embedded scenarios often focus on authentication or on providing some form of anonymity and/or privacy. A well-known cryptographic element employed to provide such security is the HMAC construction. However, reported solutions are not suitable for constrained-resource scenarios due to their heavy approaches optimized for high-speed operations. In order to cover this lack, a lightweight implementation of HMAC based on the Photon family of hash functions is given in this work. Security of the construction against differential power attacks (DPA) is analyzed using a SASEBO-II development board. Implementation and performance results for Xilinx Virtex-5 FPGAs of the HMAC structure is provide
- …