Sandstone response to salt weathering following simulated fire damage: a comparison of furnace heating and fire.

Fire has long been recognized as an agent of rock weathering. Our understanding of the impact of fire on stone comes either from early anecdotal evidence, or from more recent laboratory simulation studies, using furnaces to simulate the effects of fire. This paper suggests that knowledge derived from simulated heating experiments is based on the preconceptions of the experiment designer – when using a furnace to simulate fire, the operator decides on the maximum temperature and the duration of the experiment. These are key factors in determining the response of the stone to fire, and if these are removed from realworld observations then knowledge based on these simulations must be questioned. To explore the differences between heating sandstone in a furnace and a real fire, sample blocks of Peakmoor Sandstone were subjected to different stress histories in combination (lime rendering and removal, furnace heating or fire, frost and salt weathering). Block response to furnace heating and fire is discussed, with emphasis placed on the non-uniformity of the fire and of block response to fire in contrast to the uniform response to surface heating in a furnace. Subsequent response to salt weathering (by a 10% solution of sodium chloride and magnesium sulphate) was then monitored by weight loss. Blocks that had experienced fire showed a more unpredictable response to salt weathering than those that had undergone furnace heating – spalling of corners and rapid catastrophic weight loss were evidenced in blocks that had been subjected to fire, after periods of relative quiescence. An important physical side-effect of the fire was soot accumulation, which created a waxy, relatively impermeable layer on some blocks. This layer repelled water and hindered salt ingress, but eventually detached when salt, able to enter the substrate through more permeable areas, concentrated and crystallized behind it, resulting in rapid weight loss and accelerated decay. Copyright ©2007 John Wiley & Sons, Ltd.

Specular resentment : San-Antonio, Céline and the use of proletarian rhetoric in literary criticism

The charge of »Ressentiment« can in today's world – less from traditionally conservative quarters than from the neo-positivist discourses of particular forms of liberalism – be used to undermine the argumentative credibility of political opponents, dissidents and those who call for greater »justice«. The essays in this volume draw on the broad spectrum of cultural discourse on »Ressentiment«, both in historical and contemporary contexts. Starting with its conceptual genesis, the essays also show contemporary nuances of »Ressentiment« as well as its influence on aesthetic and literary discourse in the 20th century.

Environmental factors, clipping and fire: effects on cerrado (Brazilian savanna) native and invasive grasses

The Brazilian Cerrado houses a hugely diverse biota and is considered a conservation hotspot. One of the greatest threats to the integrity of this ecosystem is introduced African grasses, which can competitively exclude native grasses and cause changes in the microclimate and other disturbances. The Cerrado is a mosaic vegetation that provides different combinations, both spatially and temporally, of conditions that can become natural stressors to the herbaceous vegetation (water, nutrient and light availability). These mosaics are reflected in differences in relationships among native and invasive species, affecting competition and creating situations (place/season) that are more, or less, susceptible to invasion. The present study aimed to identify the different biological responses of native (Aristida recurvata, Aristida setifolia, Axonopus barbigerus, Echinolaena inflexa, Gymnopogon spicatus, Paspalum gardnerianum, Paspalum stellatum, Schizachyrium microstachyum, Schizachyrium sanguineum) and invasive (Melinis minutiflora and Andropogon gayanus) grasses to variations in natural stressors and to disturbance (fire and clipping), in order to understand changes in ecosystem functioning and competition processes between the grasses, and to understand invasion dynamics in this ecosystem. The presence of invasive species proved to affect the ecosystem functioning by increasing soil feeding activity. These differences were no longer observed in the dry season or when fires were frequent, showing that water availability and fire are more detrimental to soil feeding activity than is the vegetation. Laboratory experiments showed that both drought and flood simulated scenarios damaged both species, although the invasive species performed better under all watering conditions and responded better to fertilization. Underlying mechanisms such as the efficiency of photosynthesis and antioxidant mechanisms helped to explain this behavior. The invasive species grew faster and showed less cellular damage and a healthier photosystem, reflected in higher assimilation rates under stress. These differences between the native and invasive species were reduced with clipping, especially in dry soil with no fertilization, where the native species recovered better in relation to the pre-clipping levels. Flooding was as stressful as drought, but the invasive species can bypass this issue by growing an extensive root system, especially in the better-drained soils. Fire is more detrimental than clipping, with a slower recovery, while post-fire temperatures affect the germination of both invasive and native seeds and may be an important factor influencing the persistence of a diverse biota. This approach will finally contribute to the choice of the appropriate management techniques to preserve the Cerrado’s biodiversity.

Camp Niagara, with a historical sketch of Niagara-on-the-Lake and Niagara Camp (1906)

Historical sketch of Niagara on the Lake and Niagara Camp.

Afecto y consumo del alcohol y tabaco en personas adultas de una localidad de San Francisco de Campeche .

Tesis (Maestría en Ciencias de Enfermería con Énfasis en Salud Comunitaria) UANL, 2009.

Sermon panegírico que en honra de María Santísima en su prodigiosa imagen del Pueblito, en la función anual que le hace su ilustre cofradía con asistencia del muy ilustre ayuntamiento : predicó en la Iglesia del Convento Grande de nuestro seráfico padre San Francisco de la ciudad de Querétaro el día 14 de febrero de 1814

UANL

Virtudes y milagros en vida, y muerte del venerable padre Fr. Sebastián de Aparicio, religioso lego de la regular observancia de nuestro seráfico Padre San Francisco, e hijo de la Provincia del Santo Evangelio de México, en la Nueva España, que floreció en el Convento de la Puebla de los Angeles.

UANL

Libro de determinaciones y acuerdos de este Real Colegio de San Francisco Xavier de Querétaro, y Reales Estudios de San Ignaciio

UANL

Vida de San Francisco de Sales, obispo y principio de Ginebra

UANL