On the microstructure, growth pattern and original porosity of belemnite rostra: insights from calcitic Jurassic belemnites

Calcitic belemnite rostra are usually employed to perform paleoenvironmental studies based on geochemical data. However, several questions, such as their original porosity and microstructure, remain open, despite they are essential to make accurate interpretations based on geochemical analyses.This paper revisits and enlightens some of these questions. Petrographic data demonstrate that calcite crystals of the rostrum solidum of belemnites grow from spherulites that successively develop along the apical line, resulting in a “regular spherulithic prismatic” microstructure. Radially arranged calcite crystals emerge and diverge from the spherulites: towards the apex, crystals grow until a new spherulite is formed; towards the external walls of the rostrum, the crystals become progressively bigger and prismatic. Adjacent crystals slightly vary in their c-axis orientation, resulting in undulose extinction. Concentric growth layering develops at different scales and is superimposed and traversed by a radial pattern, which results in the micro-fibrous texture that is observed in the calcite crystals in the rostra.Petrographic data demonstrate that single calcite crystals in the rostra have a composite nature, which strongly suggests that the belemnite rostra were originally porous. Single crystals consistently comprise two distinct zones or sectors in optical continuity: 1) the inner zone is fluorescent, has relatively low optical relief under transmitted light (TL) microscopy, a dark-grey color under backscatter electron microscopy (BSEM), a commonly triangular shape, a “patchy” appearance and relatively high Mg and Na contents; 2) the outer sector is non-fluorescent, has relatively high optical relief under TL, a light-grey color under BSEM and low Mg and Na contents. The inner and fluorescent sectors are interpreted to have formed first as a product of biologically controlled mineralization during belemnite skeletal growth and the non-fluorescent outer sectors as overgrowths of the former, filling the intra- and inter-crystalline porosity. This question has important implications for making paleoenvironmental and/or paleoclimatic interpretations based on geochemical analyses of belemnite rostra.Finally, the petrographic features of composite calcite crystals in the rostra also suggest the non-classical crystallization of belemnite rostra, as previously suggested by other authors.

Juniperus navicularis - a study of Portuguese population structure and fitness

Juniperus navicularis Gand. is a dioecious endemic conifer that constitutes the understory of seaside pine forests in Portugal, areas currently threatened by increasing urban expansion. The aim of this study is to assess the conservation status of previously known populations of this species located on its core area of distribution. The study was performed in south-west coast of Portugal. Three populations varying in size and pine density were analyzed. Number of individuals, population density, spatial distribution and individual characteristics of junipers were estimated. Female cone, seed characteristics and seed viability were also evaluated. Results suggest that J. navicularis populations are vulnerable because seminal recruitment is scarce, what may lead to a reduction of genetic variability due solely to vegetative propagation. This vulnerability seems to be strongly determined by climatic constraints toward increasing aridity. Ratio between male and female shrubs did not differ from 1:1 in any population. Deviations from 1:1 between mature and non-mature plants were found in all populations, denoting population ageing. Very low seed viability was observed. A major part of described Juniperus navicularis populations have disappeared through direct habitat loss to urban development, loss of fitness in drier and warmer locations and low seed viability. This study is the first to address J. navicularis conservation, and represents a valuable first step toward this species preservation. 

New contributions to the native and alien flora in riparian habitats of the Cantabrian watershed (Northern Spain)

As a result of a floristic survey carried out in riparian habitats of northern Spain, new chorological data are provided for 9 alien and 6 native plant species. Some species are reported for the first time at regional scale, such as Carex strigosa, Helianthus x laetiflorus and Persicaria pensylvanica in Cantabria. Also noteworthy is the finding of naturalised populations of the North American grass Muhlenbergia schreberi at the Urumea river basin, which represents the second reference for the Iberian Peninsula.

El género epistolar en la prensa como visión ciudadana de la esfera pública en Colombia

A partir de un análisis temático inductivo, este artículo explora la visión ciudadana sobre la esfera pública expresada en las cartas de los lectores de los diarios El Tiempo y El Heraldo de Colombia. Los resultados muestran cómo la identidad colectiva de los lectores apareció en forma transversal en las cartas, para dar cuenta de una comunidad de adultos que se autodefine como “colombianos de bien”. El análisis reveló dos unidades de significado: posturas sobre la administración de lo público y antagonismos en la esfera pública, centrada en el conflicto político con las guerrillas. A través de estas se pudieron hacer visibles los llamamientos vívidos de los lectores al gobierno, funcionarios públicos, actores al margen de la ley y a sus compatriotas, para movilizarse para exigir cambios sociales largamente esperados.

Narrative Deliberation? On Storytelling as a Necessary Component of Public Deliberation

This paper deals with the place of narrative, that is, storytelling, in public deliberation. A distinction is made between weak and strong conceptions of narrative. According to the weak one, storytelling is but one rhetorical device among others with which social actors produce and convey meaning. In contrast, the strong conception holds that narrative is necessary to communicate, and argue, about topics such as the human experience of time, collective identities and the moral and ethical validity of values. The upshot of this idea is that storytelling should be a necessary component of any ideal of public deliberation. Contrary to recent work by deliberative theorists, who tend to adopt the weak conception of narrative, the author argues for embracing the strong one. The main contention of this article is that stories not only have a legitimate place in deliberation, but are even necessary to formulate certain arguments in the fi rst place; for instance, arguments drawing on historical experience. This claim, namely that narrative is constitutive of certain arguments, in the sense that, without it, said reasons cannot be articulated, is illustrated by deliberative theory’s own narrative underpinnings. Finally, certain possible objections against the strong conception of narrative are dispelled.

Standardization in the Pre-Columbian Pottery from El Caño, Panama: Specialization, Productivity and Consumption

The pottery found in the burials of El Cano is uniform in style to these made in the coclesanos valleys between 700 and 1000 AD. The coefficient of variability of the different pottery forms, evidence diverse standardizations values for polychrome and non-polychrome ceramics. Moreover, data of funerary contexts from the Cano recently excavated, suggest that elite has controlled ceramic production. This control over the production of certain goods reveals that these were important in the support or proper operational of the chiefdoms in Panama and mark the phase of splendour of this culture.

El color en los códices prehispánicos del México Central: identificación material, cualidad plástica y valor estético

Este artículo investiga algunos de los valores plásticos y estéticos que presidieron la selección y la preparación de las materias colorantes empleadas para iluminar los códices creados por los nahuas del México Central durante el Posclásico Tardío. Estos códices son interesantes porque análisis arqueométricos y exámenes codicológicos recientes han permitido conocer la materialidad de su capa pictórica, así como las características formales y el comportamiento de los colores en estas obras. Uno de los aportes trascendentales de estos estudios ha sido averiguar que la paleta cromática que sirvió para pintar los códices del México Central era principalmente de origen orgánico, lo que contrasta con la naturaleza de los pigmentos detectados en restos de pintura mural y en esculturas creadas por los nahuas que son sobre todo minerales. El objetivo de este artículo es reflexionar sobre las razones de esas diferencias y demostrar que el uso de los colorantes orgánicos en los códices respondía a un fin plástico específico que concordaba con el canon estético imperante en la sociedad náhuatl.

Análisis de elementos gráficos de contenido occidental en los glifos de los códices coloniales del centro de México: el caso de los antropónimos castellanos

En este trabajo presentamos el estudio de los glifos nahuas coloniales de antropónimos castellanos que contienen algún elemento occidental en su composición. Es decir, analizamos los «prestamos» que los tlacuiloque o escribas indígenas tomaron para escribirlos. Para llevarlo a cabo hemos revisado multitud de códices aunque somos conscientes de que no hemos tenido acceso a todos ellos. No obstante, consideramos que el resultado final recoge la mayor parte de ellos y ofrece datos que nos permitirá en próximos estudios relacionar antropónimos nahuas, topónimos, oficios, cargos, barrios, etc., en los que también se incluyeron elementos culturales occidentales.

Around the Origin of the Images in the Veintena Section of the "Primeros Memoriales" by fray Bernardino de Sahagún

By examining the pictorial content of the veintena section of the Primeros Memoriales, the manusctipt compiled by fray Bernardino de Sahagún, I identify new pieces of evidence on the origin of these illustrations and their authors. A carefull analisis of this material suggests that it is strongly embedded in the pre-Hispanic tradition and that it is doubtful that their iconographic sources originated in Tepeopolco, as it is widely believed.

Sherman Alexie’s "The Toughest Indian in the World": Amalgamating the Oral and the Written Traditions

This article argues that The Toughest Indian in the World (2000) by Native-American author Sherman Alexie combines elements of his tribal (oral) tradition with others coming from the Western (literary) short-story form. Like other Native writers — such as Momaday, Silko or Vizenor — , Alexie is seen to bring into his short fiction characteristics of his people’s oral storytelling that make it much more dialogical and participatory. Among the author’s narrative techniques reminiscent of the oral tradition, aggregative repetitions of patterned thoughts and strategically-placed indeterminacies play a major role in encouraging his readers to engage in intellectual and emotional exchanges with the stories. Assisted by the ideas of theorists such as Ong (1988), Evers and Toelken (2001), and Teuton (2008), this article shows how Alexie’s short fiction is enriched and revitalized by the incorporation of oral elements. The essay also claims that new methods of analysis and assessment may be needed for this type of bicultural artistic forms. Despite the differences between the two modes of communication, Alexie succeeds in blending features and techniques from both traditions, thus creating a new hybrid short-story form that suitably conveys the trying experiences faced by his characters.

Responsibility and Well-Being: Resource Integration Under Responsibilization in Expert Services

Responsibilization, or the shift of functions and risks from providers and producers to consumers, has become an increasingly common policy in service systems and marketplaces (e.g., financial, health, governmental). As responsibilization is often considered synonymous with consumer agency and well-being, the authors take a transformative service research perspective and draw on resource integration literature to investigate whether responsibilization is truly associated with well-being. The authors focus on expert services, for which responsibilization concerns are particularly salient, and question whether this expanding policy is in the public interest. In the process, they develop a conceptualization of resource integration under responsibilization that includes three levels of actors (consumer, provider, and service system), the identification of structural tensions to resource integration, and three categories of resource integration practices (access, appropriation, and management) necessary to negotiate responsibilization. The findings have important implications for health care providers, public and institutional policy makers, and other service systems, all of which must pay more active attention to the challenges consumers face in negotiating responsibilization and the resulting well-being outcomes.

Resilience of small-scale societies’ livelihoods: a framework for studying the transition from food gathering to food production

The origins of agriculture and the shift from hunting and gathering to committed agriculture is regarded as one of the major transitions in human history. Archeologists and anthropologists have invested significant efforts in explaining the origins of agriculture. A period of gathering intensification and experimentation and pursuing a mixed economic strategy seems the most plausible explanation for the transition to agriculture and provides an approach to study a process in which several nonlinear processes may have played a role. However, the mechanisms underlying the transition to full agriculture are not completely clear. This is partly due to the nature of the archeological record, which registers a practice only once it has become clearly established. Thus, points of transitions have limited visibility and the mechanisms involved in the process are difficult to untangle. The complexity of such transitions also implies that shifts can be distinctively different in particular environments and under varying historical and social conditions. In this paper we discuss some of the elements involved in the transition to food production within the framework of resilience theory. We propose a theoretical conceptual model in which the resilience of livelihood strategies lies at the intersection of three spheres: the environmental, economical, and social domains. Transitions occur when the rate of change, in one or more of these domains, is so elevated or its magnitude so large that the livelihood system is unable to bounce back to its original state. In this situation, the system moves to an alternative stable state, from one livelihood strategy to another.