A revised application of Ostrom's (Ostrom, 2007) Social-Ecological System (SES) framework to Hardin's ‘tragedy of the commons’ (Hardin, G. (1968), Science, 162(3859): 1243–1248) demonstrates that its ...institutional structure is more complex than either Hardin or Ostrom had imagined. The ‘tragedy’ arises from several interacting resources and institutions. If the grass on the pasture was not subject to appropriation, the cattle were not privately owned, or property- and contract-enforcement institutions supporting market exchange were absent, then the ‘tragedy of the commons’ would not have arisen regardless of the open-access pasture. This paper highlights the utility of the SES framework and the care required to apply it precisely to specific social-ecological situations.
Ethylene glycol loss rate constants of 1.0±0.40 h
−1 were achieved in photo Fenton systems containing concentrations of 1000 mg/l ethylene glycol. Ethylene glycol was converted to formic acid ...resulting in a loss of calculated chemical oxygen demand. Iron was not catalytic in the system which may be due to the formation of ferric oxalate complexes. The system was inhibited by elevated concentrations of sulfate and a phosphate buffer solution. The optimal pH was 3.0, with significant decreases in the degradation rates below 2.8 and above 3.2. Increased TOC loss was noted in similar UV/H
2O
2 systems indicating a potential for increased mineralization in optimized photo Fenton systems with longer residence times.
Objective (1) To determine if, after using the simulation mannequin SimMan in a wilderness “megacode” exercise, participants believe high-tech simulators are an effective tool for learning wilderness ...medicine skills. (2) To determine if participants believe high-tech simulation mannequins should be used with more or less frequency in future wilderness medicine exercises. Methods After completing a basic training session outlining the capabilities of SimMan and completing a wilderness megacode (defined as a series of progressive conditions that accumulate over time) using SimMan, participants were surveyed to ascertain whether they perceived SimMan to be an effective teaching tool for wilderness medical skills and to determine if they would like SimMan to be used with greater frequency at future wilderness medicine courses. The data were compiled and analyzed using Microsoft Excel. Results Participants found the wilderness SimMan experience to be an effective tool with an average score of 3.15 on a scale where 4 is most effective and 1 is least effective. Participants also desired to see high-tech simulation more frequently in wilderness courses with a score of 3, on a scale where 4 is more frequently and 1 is less frequently. There was little difference in responses based on previous experience with simulation. Conclusions High-tech simulation is an underused tool for wilderness medicine education. Currently, several barriers exist to its implementation in wilderness medicine. Participants in wilderness courses feel it is an effective tool and would like to see it used more frequently.
Elinor Ostrom and the Bloomington School of Political Economy is a comprehensive collection, in four volumes, of the most important contributions by Ostrom and her colleagues on central issues across ...the social sciences.
Summary
1. In this paper we test the usefulness of acoustic backscatter measurements from a 614 kHz Acoustic Doppler Current Profiler (ADCP) for the qualitative and quantitative characterisation of ...zooplankton distributions in lakes. ADCP‐based backscatter estimates were compared with frequent net hauls obtained during a calibration experiment in which the acoustic backscatter was strongly dominated by vertical migrating Chaoborus flavicans larvae.
2. The correlation between backscatter estimates and the C. flavicans concentration was very good. Vertical swimming speed of larvae, measured directly by the ADCP, was up to a maximum of 5 mm s−1 and agreed very well with the observed vertical movement of the backscatter contour lines. Although the strong backscatter from C. flavicans overwhelmed the signal from the remaining zooplankton, a good correlation between backscatter strength and the total remaining zooplankton concentration, dominated by Cyclops spp., was found for the depth and time intervals where no C. flavicans were present.
3. In addition to the calibration experiment, longer‐term ADCP measurements from different lakes revealed a strong temporal correlation between the onset of the up‐ and downward migration of zooplankton and the local sunset and sunrise.
4. We conclude that ADCPs can be used to monitor plankton distributions both temporally and spatially. It also seems possible to estimate plankton densities after appropriate calibration.
Laparoscopic pyeloplasty has evolved into the procedure of choice when definitive repair of the obstructed ureteropelvic junction is contemplated. Its main advantage over the gold standard of open ...pyeloplasty is decreased morbidity. We have utilized only three 5-mm ports in our last 15 pyeloplasties in an effort to further reduce morbidity and improve acceptance by an often-younger patient population.
Fifteen consecutive patients underwent laparoscopic transperitoneal pyeloplasty by the 5-mm port technique. Three trocars were utilized, two for the working instruments and one for a 5-mm telescope mounted on a voice-activated robotic arm (AESOP; Intuitive Surgical, Sunnyvale, CA). Three patients required an additional trocar for liver retraction. All patients underwent dismembered pyeloplasty and had indwelling double-pigtail stents placed for 4 to 6 weeks.
The mean operative time was 195 minutes (range 120-240 minutes). The average blood loss was 30 mL. None of our patients required open conversion. With a median follow-up of 10 months (range 3-15 months), all 15 patients have shown both subjective (freedom from symptoms) and objective (renal scan) improvement.
We believe our technique has further minimized the morbidity of laparoscopic pyeloplasty without compromising the outcome. The 5-mm trocars obviate fascial closure, decrease patient discomfort, and improve cosmesis. Furthermore, the use of the robotic arm eliminates the need for a surgical assistant and makes this an essentially "one-person" procedure.
The renewed interest in naphthenic acid (NA) as a wood preservative has driven the need for analytical techniques to characterize commercial supplies of NA. The compositional heterogeneity of NA ...makes analytical characterization extremely difficult. Fluoride ion chemical ionization mass spectrometry (FI-MS) has proven to be an effective technique in NA characterization. However, FI-MS is very complicated and expensive to perform. In this paper, an alternative to the FI-MS technique is presented which offers similar results with a more widely available bench-top electron impact (EI) mass spectrometer. By derivatization of NA components to their
tert.-butyldimethylsilyl analogs, the extent of molecular fragmentation is greatly decreased and strong base peaks representing the unfragmented NA constituents are obtained in the EI spectra. Molecular mass and tentative structures can be deduced based on sites of unsaturation.
Emergency Pericardiocentesis Fitch, Michael T.; Nicks, Bret A.; Pariyadath, Manoj ...
The New England journal of medicine,
03/2012, Letnik:
366, Številka:
12
Journal Article
Recenzirano
The use of emergency pericardiocentesis to aspirate fluid in patients with cardiac tamponade can be a lifesaving procedure that restores normal cardiac function and peripheral perfusion. This video ...demonstrates the procedure.
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