ABSTRACT
Early energy analyses of agriculture revealed that behind higher labor and land productivity of industrial farming, there was a decrease in energy returns on energy (EROI) invested, in comparison to more traditional organic agricultural systems. Studies on recent trends show that efficiency gains in production and use of inputs have again somewhat improved energy returns. However, most of these agricultural energy studies have focused only on external inputs at the crop level, concealing the important role of internal biomass flows that livestock and forestry recirculate within agroecosystems. Here, we synthesize the results of 82 farm systems in North America and Europe from 1830 to 2012 that for the first time show the changing energy profiles of agroecosystems, including livestock and forestry, with a multi-EROI approach that accounts for the energy returns on external inputs, on internal biomass reuses, and on all inputs invested. With this historical circular bioeconomic approach, we found a general trend towards much lower external returns, little or no increases in internal returns, and almost no improvement in total returns. This "energy trap" was driven by shifts towards a growing dependence of crop production on fossil-fueled external inputs, much more intensive livestock production based on feed grains, less forestry, and a structural disintegration of agroecosystem components by increasingly linear industrial farm managements. We conclude that overcoming the energy trap requires nature-based solutions to reduce current dependence on fossil-fueled external industrial inputs and increase the circularity and complexity of agroecosystems to provide healthier diets with less animal products. Supplementary Information: The online version contains supplementary material available at 10.1007/s13593-023-00925-5.
ABSTRACT
INTRODUCTION: Given that beta-blockers reduce the incidence of bacterial translocation in cirrhotic rats, the aim of this study was to compare the long-term incidence of spontaneous bacterial peritonitis in cirrhotic patients submitted to pharmacologic versus endoscopic treatment to prevent variceal rebleeding. PATIENTS AND METHODS: Two hundred and thirty patients with variceal hemorrhage were included in two previous randomized trials performed to compare the efficacy of medication (nadolol plus isosorbide mononitrate, n=115) versus endoscopic treatment (n=115) with sclerotherapy or ligation for the prevention of rebleeding. RESULTS: The mean follow-up was 23+/-1.4 months. The characteristics of the patients and the number of patients on long-term prophylaxis with norfloxacin were similar in both groups. The incidence of spontaneous bacterial peritonitis was lower in the medication group (9 versus 14.7%, P=NS). The probability of spontaneous bacterial peritonitis was also lower in the medication group (6 versus 12% at 1 year, 22 versus 36% at 5 years; P=0.08), due to a significantly lower probability of community-acquired spontaneous bacterial peritonitis in this group (1 versus 10% at 1 year, 18 versus 32% at 5 years; P=0.02). Patients with no hemodynamic response to therapy had a significantly higher probability to develop community-acquired spontaneous bacterial peritonitis during follow-up than hemodynamic responders (P<0.03). Long-term probability of developing community-acquired spontaneous bacterial peritonitis is lower in patients submitted to pharmacologic treatment for preventing variceal rebleeding than in those submitted to endoscopic treatment. CONCLUSION: Long-term pharmacologic prophylaxis of variceal rebleeding contributes to the prevention of community-acquired spontaneous bacterial peritonitis.
