The need for new sources of renewable energies and the rising price of fossil fuels have induced the hope that agricultural crops may be a source of renewable energy for the future. We question in ...this paper the best strategies to convert solar radiation into both energy and food. The intrinsic efficiency of the photosynthetic process is quite low (around 3%) while commercially available monocristalline solar photovoltaic (PV) panels have an average yield of 15%. Therefore huge arrays of solar panels are now envisaged. Solar plants using PV panels will therefore compete with agriculture for land. In this paper, we suggest that a combination of solar panels and food crops on the same land unit may maximise the land use. We suggest to call this an agrivoltaic system. We used Land Equivalent Ratios to compare conventional options (separation of agriculture and energy harvesting) and two agrivoltaic systems with different densities of PV panels. We modelled the light transmission at the crop level by an array of solar panels and used a crop model to predict the productivity of the partially shaded crops. These preliminary results indicate that agrivoltaic systems may be very efficient: a 35–73% increase of global land productivity was predicted for the two densities of PV panels. Facilitation mechanisms similar to those evidenced in agroforestry systems may explain the advantage of such mixed systems. New solar plants may therefore combine electricity production with food production, especially in countries where cropping land is scarce. There is a need to validate the hypotheses included in our models and provide a proof of the concept by monitoring prototypes of agrivoltaic systems.
► Agrivoltaic (AV) systems mix solar photovoltaic panels and crops on the same land unit. ► A land equivalent ratio of AV systems is a measure of their efficiency. ►
Ex ante modelling predicts a very high productivity of such AV systems. ► AV may be a win–win option to alleviate the pressure on cropland for energy production.
•Model based on rainfall thresholds was developed to forecast CSO occurrence.•CSO records for 4285 overflow structures (OS) in Quebec were analyzed.•Probability of days with CSO were used to estimate ...the rainfall threshold value.•Threshold model has demonstrated significant forecast skill for 91.3% of the OS.
Combined Sewer Overflow (CSO) has been recognized as a major environmental issue in many countries. In Canada, the proposed reinforcement of the CSO frequency regulations will result in new constraints on municipal development. Municipalities will have to demonstrate that new developments do not increase CSO frequency above a reference level based on historical CSO records. Governmental agencies will also have to define a framework to assess the impact of new developments on CSO frequency and the efficiency of the various proposed measures to maintain CSO frequency at its historic level. In such a context, it is important to correctly assess the average number of days with CSO and to define relationships between CSO frequency and rainfall characteristics. This paper investigates such relationships using available CSO and rainfall datasets for Quebec. CSO records for 4285 overflow structures (OS) were analyzed. A simple model based on rainfall thresholds was developed to forecast the occurrence of CSO on a given day based on daily rainfall values. The estimated probability of days with CSO have been used to estimate the rainfall threshold value at each OS by imposing that the probability of exceeding this rainfall value for a given day be equal to the estimated probability of days with CSO. The forecast skill of this model was assessed for 3437 OS using contingency tables. The statistical significance of the forecast skill could be assessed for 64.2% of these OS. The threshold model has demonstrated significant forecast skill for 91.3% of these OS confirming that for most OS a simple threshold model can be used to assess the occurrence of CSO.
Microvascular muscle transfer is the gold standard for reanimation following chronic facial nerve paralysis, however, despite the regenerative capacity of peripheral motor axons, poor reinnervation ...often results in sub-optimal function. We hypothesized that injection of alginate hydrogels releasing growth factors directly into donor tissue would promote reinnervation, muscle regeneration, and function. A murine model of sciatic nerve ligation and neurorrhaphy was first used to assess the ability of gel delivery of vascular endothelial growth factor (VEGF) and insulin-like growth factor-1 (IGF-1) to promote functional reinnervation. VEGF + IGF-1 gel delivery to aged mice resulted in prolonged ability to control toe movement, increased toe spreading, and improved static sciatic index score, indicative of improved sciatic nerve and neuromuscular junction function. Further, a 26% increase in muscle fiber area, and 2.8 and 3.0-fold increases in muscle contraction force and velocity, respectively, were found compared to blank alginate in the murine model. This strategy was subsequently tested in a rabbit model of craniofacial gracilis muscle transplantation. Electromyography demonstrated a 71% increase in compound muscle action potential 9 weeks after transplantation following treatment with VEGF + IGF-1 alginate, compared to blank alginate in the rabbit model. Improving functional innervation in transplanted muscle via a hydrogel source of growth factors may enhance the therapeutic outcomes of facial palsy treatments and, more broadly, muscle transplantations.
We describe the potential contribution of on-farm biogas production to reducing greenhouse gas (GHG) emissions and other environmental impacts related to livestock operations. GHG are reduced by ...production of renewable energy as a substitute for fossil fuels via reduction of fugitive GHG emissions from stored and land applied manures, as well as by reduction in use of chemical fertilizers in crop production. Anaerobic digestion (AD) biotechnologies produce biogas at average rates of 0.30, 0.25 and 0.48L/g volatile solids from swine, bovine and poultry slurries, respectively. The biogas produced is of high quality with a CH4 concentration of 60–80%. AD may be an acceptable solution to management of P surplus by precipitating up to 25% of it in batch or semi-batch operated bioreactors, and by precipitating and concentrating up to 70% of bioreactor effluent P in long term storage bottom sludge. Effluents from AD are better balanced to meet crop needs than raw manure slurries, thereby reducing the need for supplementary chemical N and P fertilizers. Both capture of energy and reduced needs for chemical fertilizers will substantially decrease the C footprint of livestock food products. On-farm biogas production contributes to more sustainable livestock operations by substantially reducing other environmental impacts related to manure management. It reduces the risk of water pollution associated with animal manure slurries (i.e., eutrophication) by removing 0.80–0.90 of soluble chemical oxygen demand. In addition, some AD eliminate zoonotic pathogens and parasites in livestock manures. AD also improves human/farm cohabitation in rural regions by reducing odour emissions by 70–95%. This reduction allows more frequent and better timing of manure land application. Both timing of application and improved nutrient balance have the potential to increase nutrient uptake by crops and minimize nutrient losses to the environment. Reduction in the viability of weed seeds during AD reduces the need for herbicides and makes bioreactor effluent more acceptable to organic farmers. Inadequate regulatory polices and incentives are obstacles to widespread implementation of AD in developed and developing countries. However, adoption of AD is an alternative which could substantially reduce the C and environmental footprint of housed livestock operations.
This article is part of the special issue entitled: Greenhouse Gases in Animal Agriculture – Finding a Balance between Food and Emissions, Guest Edited by T.A. McAllister, Section Guest Editors; K.A. Beauchemin, X. Hao, S. McGinn and Editor for Animal Feed Science and Technology, P.H. Robinson.
Clarifying the Language of Clinician Distress Dean, Wendy; Talbot, Simon G; Caplan, Arthur
JAMA : the journal of the American Medical Association,
03/2020, Letnik:
323, Številka:
10
Journal Article
Recenzirano
This Viewpoint argues that moral dilemma, moral distress, and moral injury more accurately and etiologically characterize what most people refer to as physician burnout, and proposes that this ...reconception can lead to more effective prevention strategies and targeted solutions to address physician stress, frustration, dissatisfaction, and depression.
Infections caused by antibiotic-resistant bacteria, especially the "ESKAPE" pathogens, continue to increase in frequency and cause significant morbidity and mortality. New antimicrobial agents are ...greatly needed to treat infections caused by gram-negative bacilli (GNB) resistant to currently available agents. The Infectious Diseases Society of America (IDSA) continues to propose legislative, regulatory, and funding solutions to this continuing crisis. The current report updates the status of development and approval of systemic antibiotics in the United States as of early 2013. Only 2 new antibiotics have been approved since IDSA's 2009 pipeline status report, and the number of new antibiotics annually approved for marketing in the United States continues to decline. We identified 7 drugs in clinical development for treatment of infections caused by resistant GNB. None of these agents was included in our 2009 list of antibacterial compounds in phase 2 or later development, but unfortunately none addresses the entire spectrum of clinically relevant GNB resistance. Our survey demonstrates some progress in development of new antibacterial drugs that target infections caused by resistant GNB, but progress remains alarmingly elusive. IDSA stresses our conviction that the antibiotic pipeline problem can be solved by the collaboration of global leaders to develop creative incentives that will stimulate new antibacterial research and development. Our aim is the creation of a sustainable global antibacterial drug research and development enterprise with the power in the short term to develop 10 new, safe, and efficacious systemically administered antibiotics by 2020 as called for in IDSA's "10 × '20 Initiative."
In every agroforestry system, the tree canopy reduces the incident radiation for the crop. However, cereal varieties were selected, and most crop growth models were designed for unshaded conditions, ...so both may be unsuited to agroforestry conditions and performance. In southern France, durum wheat productivity was monitored over 2 years in an agroforestry system including walnut trees and under artificial shade conditions. Yield components were measured in both full and reduced light conditions. The cereal yield was always decreased by shade; by almost 50% for the heaviest shade conditions (31% of light reduction). The main effect of the shade was the reduction in the number of grains per spike (35% at the most) and in the weight of grains (16% at the most). The mean grain weight was moderately affected, while the protein content was increased in shaded conditions (by up to 38% for artificial shade). Consequently, the protein yield per hectare was less reduced by the shade than the dry matter grain yield. A crop model (STICS) was also used to simulate the crop productivity in full light and shaded conditions, but the crop LAI and the yield components were not correctly simulated in the shade. The simulations emphasized the sensitivity of the wheat grain filling to shade during the critical period, 30 days before flowering, for yield elaboration. Further experimental and modelling studies should take into account the heterogeneity of shade intensity due to the shape of the tree crown, the width of the crop alley and the orientation of the tree rows and the modification of carbon allocation inside the plant.
Predicting the temporal and spatial variability of radiation intensity under wide-spaced tree stands is required for many applied issues in savannah-like ecosystems, orchards, agroforestry and urban ...forestry systems. Numerous authors have advocated the use of simple light interception models that approximate the crown shape with ellipsoids. They have suggested taking into account leaf clumping to improve the efficiency of these simple models, but this was never assessed. We tested this hypothesis together with the impact of including predictions of light interception by woody parts (trunks, branches). We calibrated and evaluated the model using cross-validation across eight walnut trees with field measurements of radiation intensity and spatial heterogeneity using hemispherical photographs. Leafless trees were efficiently modelled using Wood Area Density (WAD, m
2
m
−3
) for branches and an opaque cone for the trunk. We introduced a clumping parameter (μ) but this proved inefficient, clumping being highly variable amongst trees. This results from the limitations of representing the crown as an ellipsoid, a procedure too coarse to be improved by using a clumping parameter. The model proved efficient to predict the light pattern around an average tree, but was not fit for simulating the variability of individual trees. We finally discuss practical recommendations for modelling light competition in integrated agroforestry models simply.
Summary
The aim of this study was to evaluate the effect of newborn piglet weight gain during the first 2 weeks of lactation on the luminal and mucosal microbiota of the ileum and colon. The ...microbiota from high‐weight‐gain (HWG) and low‐weight‐gain (LWG) 2‐week‐old piglets was characterized by amplicon length heterogeneity PCR (LH‐PCR) and compared using diversity indices and multivariate statistical analyses. At birth, LWG piglets weighted in average 0.26 kg less than HWG piglets (p = .002). The weight difference between LWG and HWG piglets increased with time and reached 2.1 kg after 16 days of lactation (p < .0001). Based on these growth performance differences, estimated colostrum and milk intake was greater in HWG than in LWG piglets (p < .0001). Analysis of the LH‐PCR data of the microbiota using non‐metric multidimensional scaling (NMS) and blocked multiresponse permutation procedure (MRBP) revealed that the microbiota of the HWG and LWG piglets tended to differ in ileal mucosa (p = .097) and differed in colonic lumen (p = .024). The microbiota of HWG piglets had higher levels of Bacteroidetes, Bacteroides and Ruminoccocaceae, and lower proportions of Actinobacillus porcinus and Lactobacillus amylovorus when compared with those of LWG piglets. As the weight gain of nursing piglets is highly correlated with the amount of ingested colostrum and milk, the results strongly suggest that colostrum and milk intake in the first 2 weeks of life influenced the development of the gut microbiota.
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