Recycling drainage effluents using reverse osmosis powered by photovoltaic solar energy in hydroponic tomato production: Environmental footprint analysis.

Greenhouse cultivation in the Mediterranean region has undoubtedly enhanced the economic growth and has generated social benefits by making an efficient use of resources. However, these production systems caused undesirable environmental impacts. In order to move towards cleaner production in greenhouse areas, this study has assessed the potential environmental benefits and trade-offs of the integration of an on-farm reverse osmosis system powered by photovoltaic solar energy to recycle the drainage effluents from greenhouses. To that end, we compare the environmental footprint of a greenhouse tomato crop using this technology in a hydroponic system (HS), versus the conventional sanded soil 'enarenado' (CS) with free-drainage to soil. Additionally, for comparison, three independent irrigation sources (desalinated seawater with low electrical conductivity and two different mixes of underground and desalinated water, with moderate and high electrical conductivity, respectively) were evaluated. The use of desalinated seawater can help reduce the overexploitation of aquifers, although if the desalination process is not done with clean energy it also comes with a negative impact on the carbon footprint. Life Cycle Assessment (LCA) was used to analyse and evaluate six environmental impact indicators associated with these production systems and water treatments. In addition, a sensitivity analysis was conducted to explore the potential environmental benefits of increasing the use of renewable energy for desalinated water production, whilst also curbing the common over-fertilisation malpractice reported in the study area. Based on our findings, the HS with leachate treatment technology showed, compared to the CS system, a significant reduction in the eutrophication (72 %), although it did inevitably increase the depletion of fossil fuels (43 %) global warming (37 %) and acidification (32 %) impacts, due to the need for additional infrastructure and equipment. Among the inputs considered for the cultivation systems, the greenhouse structure, and the production of fertilisers and electricity for fertigation represented the highest environmental burdens. When comparing the three irrigation treatments, it was observed that the partial substitution of desalinated seawater by brackish groundwater substantially mitigated (27 %) the global warming footprint. The sensitivity analysis revealed that a significant reduction in the environmental impact is feasible.

Arbuscular mycorrhizal symbiosis alleviates detrimental effects of saline reclaimed water in lettuce plants.

The present study evaluated the effects of inoculation with arbuscular mycorrhizal fungi (AMF; Glomus iranicum var. tenuihypharum sp. nova) on the physiological performance and production of lettuce plants grown under greenhouse conditions and supplied with reclaimed water (RW; urban-treated wastewater with high electrical conductivity; 4.19 dS m(-1)). Four treatments, fresh water, fresh water plus AMF inoculation, RW and RW plus AMF inoculation, were applied and their effects, over time, analyzed. Root mycorrhizal colonization, plant biomass, leaf-ion content, stomatal conductance and net photosynthesis were assessed. Overall, our results highlight the significance of the AMF in alleviation of salt stress and their beneficial effects on plant growth and productivity. Inoculated plants increased the ability to acquire N, Ca, and K from both non-saline and saline media. Moreover, mycorrhization significantly reduced Na plant uptake. Under RW conditions, inoculated plants also showed a better performance of physiological parameters such as net photosynthesis, stomatal conductance and water-use efficiency than non-mycorrhizal plants. Additionally, the high concentration of nutrients already dissolved in reclaimed water suggested that adjustments in the calculation of the fertigation should be conducted by farmers. Finally, this experiment has proved that mycorrhization could be a suitable way to induce salt stress resistance in iceberg lettuce crops as plants supplied with reclaimed water satisfied minimum legal commercial size thresholds. Moreover, the maximum values of Escherichia coli in the reclaimed water were close to but never exceeded the international thresholds established (Spanish Royal Decree 1620/2007; Italian Decree, 2003) and hence lettuces were apt for sale.

[Construction and validation of a model to predict intraoperative hypothermia]. / Construcción y validación de un modelo predictivo de hipotermia intraoperatoria.

OBJECTIVES: Perioperative hypothermia is linked to adverse effects that increase morbidity and mortality. The objectives of this study were to identify the risk factors for intraoperative hypothermia and construct an instrument for identifying patients at high risk. MATERIALS AND METHODS: We studied patients of all ages who had undergone surgery. Patients were assigned to a design group or a validation group by means of a list of randomly generated numbers. Intraoperative hypothermia was defined by an tympanic temperature of 35.9 degrees C or less. A bivariate analysis of the design group identified the predictive factors and a multivariate analysis (logistic regression with backward elimination of nonsignificant variables) provided a predictive model. Risk scores were obtained for each variable by converting them to a 4-degree risk scale (abbreviated model). Predictive power was determined by calculating the area under the receiver-operator characteristic curve (AUC). RESULTS: We enrolled 264 consecutive patients; 200 were assigned to the design group and 64 to the validation group. In the design group, the AUC was 0.85 for the complete model and 0.83 for the abbreviated model. In the validation group, the AUC was 0.85 for the complete model and 0.82 for the abbreviated model. The P value was <.01 for all curves. CONCLUSION: Age, weight, approximate duration of surgery, and body and ambient temperature during induction were the included factors that predicted intraoperative hypothermia in a heterogeneous sample of surgical patients.

[Supplemental oxygen for the prevention of postoperative nausea and vomiting: a meta-analysis of randomized clinical trials]. / Oxígeno suplementario para la prevención de la náusea y el vómito postoperatorios: Meta-análisis de experimentos clínicos aleatorizados.

OBJECTIVE: Despite the development of antiemetic drugs, the incidence of postoperative nausea and vomiting remains between 20% and 30%. This meta-analysis examines the hypothesis that perioperative administration of supplemental oxygen reduces the incidence of these complications. METHODS: We performed a systematic search of the literature through MEDLINE, EMBASE, the Cochrane Library, reference lists, and a manual search, with no language restrictions, up to September 2007 to identify randomized clinical trials evaluating the effect o f supplemental oxygen on postoperative nausea and vomiting. The data were extracted and analyzed using the RevMan program, version 4.2.9 (Cochrane Collaboration, Oxford, UK). RESULTS: The study included 9 randomized clinical trials with a total of 1661 enrolled patients (824 assigned to the group with a higher oxygen concentration and 837 assigned to the group with a lower oxygen concentration). Perioperative supplemental oxygen has no effect on the incidence of nausea (relative risk [RR], 0.94; 95% confidence interval [CI], 0.82 to 1.08), postoperative nausea and/or vomiting (RR, 0.93; 95% CI, 0.74 to 1.17), or the need for rescue antiemetic drugs (RR, 0.90; 95% CI, 0.70 to 1.15). The incidence of vomiting, however, is reduced (RR, 0.77; 95% CI, 0.62 to 0.97). Significant differences were not found in the incidence of atelectasis (RR, 1.23; 95% CI, 0.50 to 3.00) or postoperative PaCO2 (weighted mean difference, -4.0; 95% CI, -12.3 to 4.3). CONCLUSIONS: Supplemental oxygen reduces the incidence of postoperative vomiting. Administration of supplemental oxygen could be an effective method of reducing postoperative vomiting but does not replace current indications for pharmacologic prophylaxis.