The Annual P Loss Estimator (APLE) is a spreadsheet‐based model developed for predicting annual field‐scale P loss in surface runoff and changes in soil test P. This empirically based model was ...designed for use by those without significant modeling experience. However, a significant limitation with the model is that it does not calculate runoff. Moreover, APLE is deterministic and thus predicts a single value for a given set of inputs, thereby ignoring any uncertainties associated with model inputs. Here, we describe modifications to APLE that allow users to estimate runoff using the Curve Number method. Using Monte Carlo simulations, the updated version of APLE also provides users the ability to account for model input uncertainties in estimating model prediction errors. We provide examples of using the revised version of APLE (ver. 3.0) for calculating P loss from two fields in Mississippi over a 4‐yr period and calculating the change in Mehlich‐3 P concentrations over a 9‐yr period at three locations in Maryland following cessation of P application. Both examples demonstrate that incorporating estimates of uncertainties in both measured data and model predictions provides modelers with a more realistic understanding of the model's performance.
Core Ideas
APLE 3.0 includes curve number method to predict runoff.
APLE 3.0 allows users to define uncertainties in model inputs.
APLE 3.0 calculates uncertainties in predictions of P loss and soil test P.
Background Platelet-activating factor (PAF) is an important mediator and correlates with anaphylaxis severity. How well PAF correlates with severity relative to histamine or tryptase is not known. ...Objective To analyze the levels of PAF, histamine, and tryptase as a function of severity in patients with acute allergic reactions. Methods PAF, histamine, and tryptase levels were measured in blood samples collected from 23 healthy volunteers and from 41 patients during acute allergic reactions. Reactions were stratified by severity from grade 1 (least severe) to grade 3 (most severe). Results Among the 3 reaction grades, there were significant differences by ANOVA for PAF ( P < .0001). The proportion of elevated PAF values increased across severity groups ( P = .0009). Increased PAF levels were observed in 20%, 66.7%, and 100% of the patients with grades 1, 2, and 3 allergic reactions, respectively. While the proportion of elevated histamine values increased from 40% to 57% to 70% across grades 1, 2, and 3, respectively, these were not significantly different ( P = .40). For tryptase, the proportion of elevated values increased monotonically from 0 in grade 1 to 4.8% in grade 2 to 60% in grade 3 ( P = .0002). Conclusions The PAF level was significantly elevated in proportion to the severity of acute allergic reactions. Whereas the PAF level was elevated in all patients with severe anaphylaxis, this was not true for either histamine or tryptase. Neither histamine nor tryptase showed as good correlations with severity scores as did PAF. These data are consistent with a pivotal role for PAF as a mediator of anaphylaxis.
Anaphylaxis is an acute, severe, life-threatening multisystem allergic reaction resulting from the sudden systemic release of biochemical mediators and chemotactic substances. Release of both ...preformed granule-associated mediators and newly generated lipid-derived mediators contributes to the amplification and prolongation of anaphylaxis. Platelet-activating factor (PAF) is a potent phospholipid-derived mediator the central role of which has been well established in experimental models of both immune-mediated and non–immune mediated anaphylaxis. It is produced and secreted by several types of cells, including mast cells, monocytes, tissue macrophages, platelets, eosinophils, endothelial cells, and neutrophils. PAF is implicated in platelet aggregation and activation through release of vasoactive amines in the inflammatory response, resulting in increased vascular permeability, circulatory collapse, decreased cardiac output, and various other biological effects. PAF is rapidly hydrolyzed and degraded to an inactive metabolite, lysoPAF, by the enzyme PAF acetylhydrolase, the activity of which has shown to correlate inversely with PAF levels and predispose to severe anaphylaxis. In addition to its role in anaphylaxis, PAF has also been implicated as a mediator in both allergic and nonallergic inflammatory diseases, including allergic rhinitis, sepsis, atherosclerotic disease, and malignancy, in which PAF signaling has an established role. The therapeutic role of PAF antagonism has been investigated for several diseases, with variable results thus far. Further investigation of its role in pathology and therapeutic modulation is highly anticipated because of the pressing need for more selective and targeted therapy for the management of severe anaphylaxis.
In cold regions, nutrient losses from dairy agroecosystems are a longstanding and recurring problem, especially when manure is applied during winter over snow‐covered frozen soils. This study ...evaluated two tillage (fall chisel tillage CT and no‐tillage NT) and three manure‐type management treatments (unmanured control, liquid manure <5% solids, and solid manure >20% solids). The liquid and solid manure used in this study were from the same animal species (Bos taurus) and facility. The six management treatments were field tested in south‐central Wisconsin during the winters (November–April) of 2017–2018 and 2018–2019 with a complete factorial design. Seasonal runoff losses were significantly lower from fall CT compared with NT during both seasons. Manure applications (both liquid and solid) on top of snow significantly increased most of the nutrients (NH4+, dissolved reactive phosphorus, total Kjeldahl nitrogen, and total phosphorus) in runoff compared with unmanured control. Irrespective of tillage and multiple runoff events, solid manure was present on the surface for longer periods, potentially releasing nutrients each time it interacted with runoff. In contrast, liquid manure infiltrated the snowpack and was partly lost with snowmelt and infiltrated soil depending upon soil frost and surface conditions. Overall, results indicate that wintertime manure applications over snow‐covered frozen soils pose a risk of nutrient loss irrespective of tillage and manure type, but in unavoidable situations, prioritizing tillage × manure type combination can help reduce losses.
Core Ideas
Fall chisel tillage reduced wintertime runoff and nutrient losses compared with no‐tillage.
Manure application on snow‐covered frozen soil significantly increased runoff nutrient loads.
Solid manure remained on the soil surface longer than liquid manure.
Winter manure application should consider manure characteristics and field storage capacities.
Background Animal and human data show that platelet-activating factor (PAF) mediates the life-threatening manifestations of anaphylaxis. Although administration of epinephrine is the mainstay of ...therapy of acute anaphylaxis, the interaction between epinephrine and PAF has not been studied. In particular, the effect of the timing of epinephrine administration on the action of PAF has not been examined. Objective Using human vascular smooth muscle cells (HVSMCs), we examined the effect of timing of epinephrine addition on the action of PAF. Methods The effect of epinephrine on PAF-mediated prostaglandin E2 (PGE2 ) release from human aortic smooth muscle cells was examined. Epinephrine was added at various times before and after PAF stimulation. Results HVSMCs stimulated with PAF released PGE2 in a concentration- and time-dependent manner. Whereas preincubation of HVSMCs with epinephrine before the addition of PAF suppressed PGE2 release, treatment with epinephrine after PAF stimulation was less effective with time after PAF stimulation. PGE2 release was suppressed by means of preincubation with 8-bromo–cyclic AMP and forskolin. Conclusions PAF induced PGE2 release from HVSMCs in a concentration- and time-dependent manner, and early addition of epinephrine was essential for the control of PAF-induced PGE2 release. Epinephrine was most effective when administered before stimulation with PAF but was progressively less effective with time after PAF stimulation.
Corn stover has potential as a bioenergy feedstock in North America. We simulated production costs for stover harvest (three-pass and two-pass with baling or chopping, and single-pass with baling or ...chopping) and on-farm storage (outdoor and indoor bales, outdoor wrapped bales, and chopped stover in bags, bunks, or piles). For three- and two-pass harvest, chopping was 33–45% more expensive than baling. For baling and chopping, two-pass harvest was 25% cheaper than three-pass. Single-pass chopping harvests were on average 42% cheaper than three-pass or two-pass chopping. Single-pass baling was cheaper (4–31%) than multi-pass baling at low rates of stover collection, but more expensive (1–39%) at high rates of collection. For bales, outdoor storage of wrapped bales was cheapest. Outdoor, unwrapped bale storage, even with 12% dry matter loss, was cheaper than indoor storage. For chopped stover, storage in bags was always cheapest, followed by piles, and then bunkers. With harvest and storage together, there were four least cost systems: single-pass, ear-snap baling with wrapped bale storage; single-pass chopping with silage bag storage; and two-pass baling with wrapped-bale storage. A second group of harvest/storage systems was 25% more expensive, including single-pass, whole-plant baling with wrapped-bale storage; two-pass chopping with silage-bag storage; and three-pass baling with wrapped-bale storage. The three-pass chop harvest with silage bag storage was most expensive. Our analysis suggests all harvest and farm storage systems have tradeoffs and several systems can be economically and logistically viable.
•Corn stover has potential as a bioenergy feedstock in North America.•We compared production costs for several stover harvest and storage options.•There were four harvest and storage systems that provided the least cost.•Cost for the cheapest systems was only 25% less then several other systems.•Most harvest/storage systems have tradeoffs and several can be economically viable.
Decades of fertilizer and manure applications have led to a buildup of phosphorus (P) in agricultural soils and sediments, commonly referred to as legacy P. Legacy P can provide a long-term source of ...P to surface waters where it causes eutrophication. Using a suite of numerical models, we investigated the influence of legacy P on water quality in the Yahara Watershed of southern Wisconsin, USA. The suite included Agro-IBIS, a terrestrial ecosystem model; THMB, a hydrologic and nutrient routing model; and the Yahara Water Quality Model which estimates water quality indicators in the Yahara chain of lakes. Using five alternative scenarios of antecedent P storage (legacy P) in soils and channels under historical climate conditions, we simulated outcomes of P yield from the landscape, lake P loading, and three lake water quality indicators. Legacy P had a significant effect on lake loads and water quality. Across the five scenarios for Lake Mendota, the largest and most upstream lake, average P yield (kg ha⁻¹) varied by -41 to +22%, P load (kg y⁻¹) by-35 to +14%, summer total P (TP) concentration (mg l⁻¹) by -25 to +12%, Secchi depth (m) by -7 to +3 %, and the probability of hypereutrophy by -67 to +34 %, relative to baseline conditions. The minimum storage scenario showed that a 35% reduction in present-day loads to Lake Mendota corresponded with a 25% reduction in summer TP and smaller reductions in the downstream lakes. Water quality was more vulnerable to heavy rainfall events at higher amounts of P storage and less so at lower amounts. Increases in heavy precipitation are expected with climate change; therefore, water quality could be protected by decreasing P reserves.
In this study we conducted a sensitivity and uncertainty analysis using the Annual P Loss Estimator (APLE) model focusing on model predictions of soil test phosphorus (STP). We calculated and ...evaluated the sensitivity coefficients of predicted STP and changes in STP using 1‐ and 10‐yr simulations with and without P application. We also compared two methods for estimating prediction uncertainties: first‐order variance approximation (FOVA) and Monte Carlo simulation (MCS). Finally, we compared uncertainties in APLE‐predicted STP with uncertainties in measured STP collected from multiple sites in Maryland under different manuring and cropping treatments. Results from our sensitivity analysis showed that predicted STP and changes in STP for 1‐yr simulations without P inputs were most sensitive to initial STP, whereas model STP predictions were most sensitive to manure and fertilizer application rates when sensitivity analyses included P inputs. For the 10‐yr simulations without P application inputs, the range in sensitivity coefficients for crop uptake and precipitation were much greater than for the 1‐yr simulations. Prediction uncertainties from FOVA were comparable to those from MCS for model input uncertainties up to 50%. Using FOVA to calculate APLE STP prediction uncertainties using the Maryland data set, the mean measured STP for nearly all site years fell within the 95% confidence intervals of the STP prediction uncertainties. Our results provide users of APLE insight into what model inputs require the most careful measurement when using the model to predict changes in STP under conditions of P drawdown (i.e., no P application) or P buildup.
Core Ideas
Initial soil test phosporus (STP) is most important input in predicting STP when P application is not modeled.
Fertilizer and manure rates are most important inputs when predicting STP following P application.
First‐order variance approximation is an appropriate method to estimate prediction uncertainties in STP with APLE.
Prediction uncertainties generally overlap measured STP across treatments.
Agricultural phosphorus (P) management is a research and policy issue due to P loss from fields and water quality degradation. Better information is needed on the risk of P loss from dairy manure ...applied in winter or when runoff is imminent. We used the SurPhos computer model and 108 site–years of weather and runoff data to assess the impact of these two practices on dissolved P loss. Model results showed that winter manure application can increase P loss by 2.5 to 3.6 times compared with non‐winter applications, with the amount increasing as the average runoff from a field increases. Increased P loss is true for manure applied any time from late November through early March, with a maximum P loss from application in late January and early February. Shifting manure application to fields with less runoff can reduce P loss by 3.4 to 7.5 times. Delaying manure application when runoff is imminent can reduce P loss any time of the year, and sometimes quite significantly, but the number of times that application delays will reduce P loss is limited to only 3 to 9% of possible spreading days, and average P loss may be reduced by only 15% for winter‐applied manure and 6% for non‐winter‐applied manure. Overall, long‐term strategies of shifting manure applications to low runoff seasons and fields can potentially reduce dissolved P loss in runoff much more compared with near‐term, tactical application decisions of avoiding manure application when runoff is imminent.
Core Ideas
Winter application of dairy manure can significantly increase P loss in surface runoff.
Producers have few options to reduce P manure loss by avoiding near‐term runoff.
Models can help quantify the effect of management on manure P loss in runoff.
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