Evaluation of Reclaimer Sludge Disposal from Post-combustion CO2 Capture

AbstractAn important environmental issue for amine-based post-combustion CO2 capture is the generation of reclaimer sludge containing degradation products and impurities that must be disposed. This paper evaluated the environmental fate of reclaimer wastes generated from three amine-based solvents (monoethanolamine, piperazine, and a methyldiethanolamine/piperazine blend) used for CO2 capture at a pulverized coal and a natural-gas combined cycle power plant (900 and 810 MWe, respectively) with typical flue gas compositions. The solvent loss and impurities and degradation accumulation in the CO2 capture units were modeled. A techno-economic analysis of different reclaiming technologies was conducted. The reclaimer sludge was classified based on US and EU regulations for hazardous waste, and alternative options for reclaimer sludge disposal were evaluated

Mating system, population genetics, and phylogeography of the devil’s garden ant, Myrmelachista schumanni, in the Peruvian Amazon

Devil’s gardens are a remarkable feature of Amazonian rainforests. These clearings result from the cultivation of ant-plants by their symbiotic ant, Myrmelachista schumanni. Each devil’s garden is inhabited by a single M. schumanni colony, often with millions of workers and thousands of queens. Through a combination of field surveys and microsatellite genotyping, we examined M. schumanni colony structure, mating system, dispersal, and phylogeography. We discovered that the reproduction of M. schumanni is weakly seasonal, exhibits facultative polyandry, and involves split sex ratios potentially leading to sex-biased dispersal. Surprisingly, we observed only very weak clustering of genetic variation, either within or between devil’s gardens. We hypothesize that the apparent absence of geographical structure results from the unusually high level of genetic differentiation between colonies. This study adds intriguing observations to the scarce literature about the reproduction and phylogeography of Amazonian ants.We thank the Dirección General Forestal y de Fauna Silvestre of the Ministerio de Agricultura in Peru for permits (Nos. 0299-2011-AG-DGFFS-DGEFFS, 0046-2014-MINAGRI-DGFFS-DGEFFS). We are grateful to A. Coral for assistance in the field. This work was supported by FQEB Grant RFP-12-06 from the National Philanthropic Trust to NEP and MEF, NSF SES-0750480 to NEP and the Natural Sciences and Engineering Research Council of Canada to MEF

Sporadic pollen consumption among tropical ants

Although palynivory, or pollen consumption, is widespread in other Hymenoptera, there are few accounts of palynivory in ants. We subjected adult workers and larvae from 77 species of tropical ants to acetolysis, a process that dissolves most organic material but leaves behind pollen grains. Ants of 38 species contained pollen grains, suggesting that sporadic, opportunistic pollen consumption by ants is common, but not ubiquitous, in tropical forests.We would like to thank CICRA and the New Guinea Binatang Research Center for logistical support. The comments of two anonymous reviewers improved the manuscript. The Peruvian Ministry of Agriculture provided permits. Vouchers specimens are in ant collections at the Harvard Museum of Comparative Zoology (MCZ), the Centro de Ecologia y Biodiversidad (CEBIO) in Lima, Peru, and the Czech Academy of Sciences (CAS). We acknowledge funding from an NSERC Discovery Grant (MEF), an Ontario MEDI Early Researcher Award (MEF), an Ontario Graduate Scholarship (ARC), Sigma Xi (ARC), the Pierce Lab at Harvard (JGS, EY), a Putnam Expedition Grant (JGS), and the Czech Science Foundation (EY, grant number P505/10/0673)

Mobile phone-connected wearable motion sensors to assess postoperative mobilization

peer reviewedBackground: Early mobilization after surgery reduces the incidence of a wide range of complications. Wearable motion sensors measure movements over time and transmit this data wirelessly, which has the potential to monitor patient recovery and encourages patients to engage in their own rehabilitation. Objective: We sought to determine the ability of off-the-shelf activity sensors to remotely monitor patient postoperative mobility. Methods: Consecutive subjects were recruited under the Department of Neurosurgery at Columbia University. Patients were enrolled during physical therapy sessions. The total number of steps counted by the two blinded researchers was compared to the steps recorded on four activity sensors positioned at different body locations. Results: A total of 148 motion data points were generated. The start time, end time, and duration of each walking session were accurately recorded by the devices and were remotely available for the researchers to analyze. The sensor accuracy was significantly greater when placed over the ankles than over the hips (P<.001). Our multivariate analysis showed that step length was an independent predictor of sensor accuracy. On linear regression, there was a modest positive correlation between increasing step length and increased ankle sensor accuracy (r=.640, r2=.397) that reached statistical significance on the multivariate model (P=.03). Increased gait speed also correlated with increased ankle sensor accuracy, although less strongly (r=.444, r2=.197). We did not note an effect of unilateral weakness on the accuracy of left- versus right-sided sensors. Accuracy was also affected by several specific measures of a patient’s level of physical assistance, for which we generated a model to mathematically adjust for systematic underestimation as well as disease severity. Conclusions: We provide one of the first assessments of the accuracy and utility of widely available and wirelessly connected activity sensors in a postoperative patient population. Our results show that activity sensors are able to provide invaluable information about a patient’s mobility status and can transmit this data wirelessly, although there is a systematic underestimation bias in more debilitated patients