Speciation and Mobilization of Toxic Heavy Metal Ions by Methanogenic Bacteria

HWRIC Project HWR 92-09

Nurse rock microclimates significantly buffer exposure to freezing T temperature and moderate summer temperature

Nurse tree canopies mitigate exposure to freezing temperatures that could result in injury or mortality to the saguaro cactus (Carnegiea gigantea). Abiotic objects have been hypothesized to provide similar beneficial microclimates. We used data loggers at 11 nurse rock sites to record daily daytime summer maximum and winter nighttime minimum temperatures at Saguaro National Park, Arizona, to examine the effectiveness of rocks to moderate seasonal temperature extremes in the microclimate. Temperatures at rock sites averaged 2 °C warmer than exposed open control sites in winter. We found that the efficiency of rocks to act as insulators significantly increased as temperature at control sites decreased, consistent with studies of tree canopies, and that the insulation effect lasted throughout the night. In summer, rocks reduced exposure to maximum temperatures but did not offer significantly more cooling at higher temperatures. Our results suggest that the protection from freezing temperature offered by rocks in winter is more ecologically beneficial to the saguaro than extreme temperature amelioration during summer in the cold-limited frontiers of the species’ range

“Of Gods and Men” : selected print media coverage of natural disasters and industrial failures in three Westminster countries

This article examines selected print media coverage of a domestic natural disaster and domestic industrial failure in each of three Westminster countries: Australia, Canada, and the UK. It studies this coverage from several perspectives: the volume of coverage; the rate at which the articles were published; the tone of the headlines; and a content analysis of the perceived performance of key public and private institutions during and following the events. Its initial findings reveal that the natural disasters received more coverage than the industrial failures in each of the newspapers considered. There was also no significant difference in the publication rate across event type or newspaper. In each case, government was assessed at least as frequently and negatively as non-government actors, particularly during and following industrial failures. The manner in which government and non-government actors were assessed following these events suggests that, contrary to government claims that owners and operators of critical infrastructure (CI) are responsible for its successful operation, government in fact is “in the frame” as frequently as the industry owners and operators are. In addition, the negative assessments of governments following industrial failures in particular may prompt over-reaction by policy makers to industrial failures and under-reaction to natural disasters. This inconsistency is indeed ironic because the latter occur more often and cost more, both financially and socially. We reviewed 340 newspaper articles from three different newspapers: The Australian’s coverage of the Canberra bushfires and the Waterfall train accident, The Globe and Mail’s (Canada) coverage of Hurricane Juan and the de la Concorde overpass collapse, and The Daily Telegraph’s (UK) coverage of the 2007 floods and the Potters Bar train wreck. Our sample size is small; our ability to compare across newspapers and countries limited. Further research is warranted

Stochastic Fire Modeling of a Montane Grassland-Forest Landscape in the Valles Caldera National Preserve, New Mexico, USA

Montane ecosystems of the western United States have experienced dramatic changes in their fire regimes over the last 150 years. Fire behavior modeling enables understanding of how ecosystem changes have altered past fire regimes. The Valles Caldera National Preserve in the Jemez Mountains, northern New Mexico, contains one of the largest montane grasslands in North America. This area is used for multiple uses ranging from logging to grazing and recreation. These important ecosystems have experienced increased fuel loads and stem densities resulting from a century of fire exclusion and tree encroachment, resulting in potentially anomalous fire behavior. We investigated whether fire pathways tend to spread along the grassland-forest ecotone or if fire would spread directly across grasslands under extreme fire weather conditions. We used the program FlamMap to model fire behavior under a variety of weather and fuel conditions. Fire spread pathways and burn perimeters were computed for the 50th, 90th, and 99th percentiles of historic weather conditions. The results are compiled into a probability surface that represents the most parsimonious pathways of fire spread in this landscape. We found that pathways were related to the origin of ignition; fires tended to spread around the ecotone, facilitating fire spread to adjacent grasslands. These results, complemented with fire history studies in dendrochronology and empirical observations of the Las Conchas Fire in 2011, further the understanding of the role and dynamics of fire in maintaining the montane-grassland conifer ecotone, and can guide efforts to restore a landscape affected by the effects of fire exclusion

How helpful are Academic Advisors for College Students?

“Advising is an essential element of student success,” (Sayles & Shelton, 2005, p. 99). There seems to be a correlation between quality academic advising and student retention among schools that purposely pursue high quality in advising their students (Bahr, P. R., 2008; Fields & Barrett, 1996; Sayles & Shields, 2005). Though there are existing forms of academic advising within colleges and universities, the structures and goals for each strategy seem to differ. For example, local nursing schools were seeking to improve the quality of nursing education and retention through their advisory programs (Sayles & Shelton, 2005). In this article, the schools are advised to access individuals’ learning styles prior to setting any form of advisory per student. Once the student is placed into the advisory program, he or she is encouraged to get to know his or her advisor and participate in the Learner Academic Action Plan, a devised plan which encourages students to spend at least three hours studying per week. The action plan also assesses the student’s life using two components: FRED (Fun, Rest, Exercise, and Diet) and PAL (Praise, Advice, and Listening). Component FRED (2005) encourages students to pursue fun and pleasure at least four hours out of the week, which seems rather shocking to the experimenter because she hadn’t read any material accessing the importance of leisure time in regards to academic advising or academic success prior to reading this article

Overheard At The Day Care

https://works.swarthmore.edu/alum-books/3513/thumbnail.jp

Nurse rock microclimates significantly buffer exposure to freezing T temperature and moderate summer temperature

Nurse tree canopies mitigate exposure to freezing temperatures that could result in injury or mortality to the saguaro cactus (Carnegiea gigantea). Abiotic objects have been hypothesized to provide similar beneficial microclimates. We used data loggers at 11 nurse rock sites to record daily daytime summer maximum and winter nighttime minimum temperatures at Saguaro National Park, Arizona, to examine the effectiveness of rocks to moderate seasonal temperature extremes in the microclimate. Temperatures at rock sites averaged 2 °C warmer than exposed open control sites in winter. We found that the efficiency of rocks to act as insulators significantly increased as temperature at control sites decreased, consistent with studies of tree canopies, and that the insulation effect lasted throughout the night. In summer, rocks reduced exposure to maximum temperatures but did not offer significantly more cooling at higher temperatures. Our results suggest that the protection from freezing temperature offered by rocks in winter is more ecologically beneficial to the saguaro than extreme temperature amelioration during summer in the cold-limited frontiers of the species’ range

[Jeu de tarot à enseignes italiennes de Marseille, dit "tarot Conver"] : [jeu de cartes, estampe]

Référence bibliographique : Seguin, Paul Marteau, 409Référence bibliographique : Depaulis, Tarot 1984, 41Appartient à l’ensemble documentaire : JeuCartCarte à joue

[Jeu de tarot à enseignes italiennes de Marseille, dit "tarot Conver"] : [jeu de cartes, estampe]

Référence bibliographique : Seguin, Paul Marteau, 409Référence bibliographique : Depaulis, Tarot 1984, 41Appartient à l’ensemble documentaire : JeuCartCarte à joue

Design and evaluation of a new fully microwave-assisted liquid sample introduction device for inductively coupled plasma atomic emission spectrometry

A new fully microwave-assisted liquid sample introduction system (MASIS) is presented and evaluated in Inductively Coupled Plasma Atomic Emission Spectrometry (ICP-AES). The device employs a single TM010 microwave cavity for the simultaneous aerosol generation and desolvation. The different experimental requirements of both physical processes demand a careful system design and a judicious selection of the experimental conditions. The behavior of the MASIS depends on the: (i) microwave power; (ii) nebulizer nozzle inner diameter; (iii) sample uptake rate; and, (iv) matrix nature (i.e. acids, salts) and concentration. Thus, optimum operating conditions are obtained when increasing the microwave power, the matrix concentration and the sample uptake rate as well as when decreasing the nebulizer nozzle inner diameter. The analytical figures of merit afforded by the MASIS in ICP-AES are compared to those obtained with: (1) a pneumatic concentric nebulizer coupled to a cyclonic spray chamber (CS); (2) a microwave thermal nebulizer (MWTN) coupled to a cyclonic spray chamber; and (3) a pneumatic nebulizer coupled to a microwave desolvation system (MWDS). MASIS provides limits of detection up to 50 times lower than those obtained with the CS and up to 8 times lower than those with the MWTN and MWDS. No significant difference in the signal precision between the different devices tested is observed (i.e. 2–5%). Regarding the wash-out times, both MASIS and MWDS show the highest values of this parameter (i.e. 70 s) due to their higher inner volume. Wash-out time values for both MWTN and CS are lower than 30 s