The risk of recurrent pancreatitis after first episode of acute pancreatitis in relation to etiology and severity of disease: A systematic review, meta-analysis and meta-regression analysis.

BACKGROUND AND AIM: The study aims to determine and quantify the stratified risk of recurrent pancreatitis (RP) after the first episode of acute pancreatitis in relation to etiology and severity of disease. METHODS: A systematic review and meta-analysis in compliance with PRISMA statement standards was conducted. A search of electronic information sources was conducted to identify all studies investigating the risk of RP after the first episode of acute pancreatitis. Proportion meta-analysis models using random effects were constructed to calculate the weighted summary risks of RP. Meta-regression was performed to evaluate the effect of different variables on the pooled outcomes. RESULTS: Analysis of 57,815 patients from 42 studies showed that the risk of RP after first episode was 19.8% (95% confidence interval [CI] 17.5-22.1%). The risk of RP was 11.9% (10.2-13.5%) after gallstone pancreatitis, 28.7% (23.5-33.9%) after alcohol-induced pancreatitis, 30.3% (15.5-45.0%) after hyperlipidemia-induced pancreatitis, 38.1% (28.9-47.3%) after autoimmune pancreatitis, 15.1% (11.6-18.6%) after idiopathic pancreatitis, 22.0% (16.9-27.1%) after mild pancreatitis, 23.9% (12.9-34.8%) after moderate pancreatitis, 21.6% (14.6-28.7%) after severe pancreatitis, and 6.6% (4.1-9.2%) after cholecystectomy following gallstone pancreatitis. Meta-regression confirmed that the results were not affected by the year of study (P = 0.541), sample size (P = 0.064), length of follow-up (P = 0.348), and age of patients (P = 0.138) in the included studies. CONCLUSIONS: The risk of RP after the first episode of acute pancreatitis seems to be affected by the etiology of pancreatitis but not the severity of disease. The risks seem to be higher in patients with autoimmune pancreatitis, hyperlipidemia-induced pancreatitis, and alcohol-induced pancreatitis and lower in patients with gallstone pancreatitis and idiopathic pancreatitis.

Poorly drained depressions can be hotspots of nutrient leaching from agricultural soils.

Much of the US Corn Belt has been drained with subsurface tile to improve crop production, yet poorly drained depressions often still flood intermittently, suppressing crop growth. Impacts of depressions on field-scale nutrient leaching are unclear. Poor drainage might promote denitrification and physicochemical retention of phosphorus (P), but ample availability of water and nutrients might exacerbate nutrient leaching from cropped depressions. We monitored nitrate, ammonium, and reactive P leaching across multiple depression-to-upland transects in north-central Iowa, using resin lysimeters buried and retrieved on an annual basis. Crops included conventional corn/soybean (Zea mays/Glycine max) rotations measured at fields with and without a winter rye (Secale cereale) cover crop, as well as juvenile miscanthus (Miscanthus × giganteus), a perennial grass. Leaching of nitrogen (N) and P was greater in depressions than in uplands for most transects and years. The median difference in nutrient leaching between paired depressions and uplands was 56 kg N ha-1 year-1 for nitrate (p = 0.0008), 0.6 kg N ha-1 year-1 for ammonium (p = 0.03), and 2.4 kg P ha-1 year-1 for reactive P (p = 0.006). Transects managed with a cover crop or miscanthus tended to have a smaller median difference in nitrate (but not ammonium or P) leaching between depressions and uplands. Cropped depressions may be disproportionate sources of N and P to downstream waters despite their generally poor drainage characteristics, and targeted management with cover crops or perennials might partially mitigate these impacts for N, but not necessarily for P.

Photosynthetic decline in aging perennial grass is not fully explained by leaf nitrogen.

Aging in perennial plants is traditionally observed in terms of changes in end-of-season biomass; however, the driving phenological and physiological changes are poorly understood. We found that 3-year-old (mature) stands of the perennial grass Miscanthus×giganteus had 19-30% lower Anet than 1-year-old M.×giganteus (juvenile) stands; 10-34% lower maximum carboxylation rates of Rubisco and 34% lower light-saturated Anet (Asat). These changes could be related to nitrogen (N) limitations, as mature plants were larger and had 14-34% lower leaf N on an area basis (Na) than juveniles. However, N fertilization restored Na to juvenile levels but compensated only 50% of the observed decline in leaf photosynthesis with age. Comparison of leaf photosynthesis per unit of leaf N (PNUE) showed that mature stands had at least 26% lower PNUE than juvenile stands across all N fertilization rates, suggesting that other factors, besides N, may be limiting photosynthesis in mature stands. We hypothesize that sink limitations in mature stands could be causing feedback inhibition of photosynthesis which is associated with the age-related decline in photosynthesis.

Response of Total (DNA) and Metabolically Active (RNA) Microbial Communities in Miscanthus × Giganteus Cultivated Soil to Different Nitrogen Fertilization Rates.

Miscanthus × giganteus is a promising high-yielding perennial plant to meet growing bioenergy demands; however, the degree to which the soil microbiome affects its nitrogen cycling and subsequently, biomass yield remains unclear. In this study, we hypothesize that contributions of metabolically active soil microbial membership may be underestimated with DNA-based approaches. We assessed the response of the soil microbiome to nitrogen availability in terms of both DNA and RNA soil microbial communities from the Long-term Assessment of Miscanthus Productivity and Sustainability (LAMPS) field trial. DNA and RNA were extracted from 271 samples, and 16S small subunit (SSU) rRNA amplicon sequencing was performed to characterize microbial community structure. Significant differences were observed in the resulting soil microbiomes and were best explained by the sequencing library of origin, either DNA or RNA. Similar numbers of membership were detected in DNA and RNA microbial communities, with more than 90% of membership shared. However, the profile of dominant membership within DNA and RNA differed, with varying proportions of Actinobacteria and Proteobacteria and Firmicutes and Proteobacteria. Only RNA microbial communities showed seasonal responses to nitrogen fertilization, and these differences were associated with nitrogen-cycling bacteria. The relative abundance of bacteria associated with nitrogen cycling was 7-fold higher in RNA than in DNA, and genes associated with denitrifying bacteria were significantly enriched in RNA, suggesting that these bacteria may be underestimated with DNA-only approaches. Our findings indicate that RNA-based SSU characterization can be a significant and complementing resource for understanding the role of soil microbiomes in bioenergy crop production. IMPORTANCEMiscanthus × giganteus is a promising candidate for bioeconomy cropping systems; however, it remains unclear how the soil microbiome supplies nitrogen to this low-input crop. DNA-based techniques are used to provide community characterization, but may miss important metabolically active taxa. By analyzing both DNA- and actively transcribed RNA-based microbial communities, we found that nitrogen cycling taxa in the soil microbiome may be underestimated using only DNA-based approaches. Accurately understanding the role of microbes and how they cycle nutrients is important for the development of sustainable bioenergy crops, and RNA-based approaches are recommended as a complement to DNA approaches to better understand the microbial, plant, and management interactions.

Water Quality Effects of Economically Viable Land Use Change in the Mississippi River Basin under the Renewable Fuel Standard.

Demand for biofuel production driven by the Renewable Fuel Standard (RFS2) has coincided with increased land in corn production and increasing nitrogen (N) loss to the Gulf of Mexico. Diversifying cropland with perennial energy crops (miscanthus and switchgrass) may reduce N loss and improve water quality. However, the extent of these benefits depends on the mix of biomass feedstocks (corn stover, perennials) incentivized by the RFS2 and the extent to which energy crops displace N-intensive row crops. We developed an integrated economic-biophysical model to quantify the water quality impacts of three potential policy scenarios that provided corn ethanol at levels before the RFS2 (RFS1 baseline); 15 billion gallons of corn ethanol (corn ethanol only); or 16 billion gallons of cellulosic ethanol in addition to corn ethanol (corn + cellulosic ethanol). Our results showed that economically optimal locations for perennial energy crop production were distributed across idle cropland with lower intrinsic N loss than active cropland. We found stover removal incentivized by the RFS2 offset N loss benefits of perennial energy crops. This finding suggests that targeted incentives for N loss reduction are needed to supplement the RFS2 to induce displacement of N-intensive row crops with energy crops to reduce N losses.

A Systems Modeling Approach to Forecast Corn Economic Optimum Nitrogen Rate.

Historically crop models have been used to evaluate crop yield responses to nitrogen (N) rates after harvest when it is too late for the farmers to make in-season adjustments. We hypothesize that the use of a crop model as an in-season forecast tool will improve current N decision-making. To explore this, we used the Agricultural Production Systems sIMulator (APSIM) calibrated with long-term experimental data for central Iowa, USA (16-years in continuous corn and 15-years in soybean-corn rotation) combined with actual weather data up to a specific crop stage and historical weather data thereafter. The objectives were to: (1) evaluate the accuracy and uncertainty of corn yield and economic optimum N rate (EONR) predictions at four forecast times (planting time, 6th and 12th leaf, and silking phenological stages); (2) determine whether the use of analogous historical weather years based on precipitation and temperature patterns as opposed to using a 35-year dataset could improve the accuracy of the forecast; and (3) quantify the value added by the crop model in predicting annual EONR and yields using the site-mean EONR and the yield at the EONR to benchmark predicted values. Results indicated that the mean corn yield predictions at planting time (R2 = 0.77) using 35-years of historical weather was close to the observed and predicted yield at maturity (R2 = 0.81). Across all forecasting times, the EONR predictions were more accurate in corn-corn than soybean-corn rotation (relative root mean square error, RRMSE, of 25 vs. 45%, respectively). At planting time, the APSIM model predicted the direction of optimum N rates (above, below or at average site-mean EONR) in 62% of the cases examined (n = 31) with an average error range of ±38 kg N ha-1 (22% of the average N rate). Across all forecast times, prediction error of EONR was about three times higher than yield predictions. The use of the 35-year weather record was better than using selected historical weather years to forecast (RRMSE was on average 3% lower). Overall, the proposed approach of using the crop model as a forecasting tool could improve year-to-year predictability of corn yields and optimum N rates. Further improvements in modeling and set-up protocols are needed toward more accurate forecast, especially for extreme weather years with the most significant economic and environmental cost.

Description and Codification of Miscanthus × giganteus Growth Stages for Phenological Assessment.

Triploid Miscanthus × giganteus (Greef et Deu. ex Hodkinson et Renvoize) is a sterile, perennial grass used for biomass production in temperate environments. While M. × giganteus has been intensively researched, a scale standardizing description of M. × giganteus morphological stages has not been developed. Here we provide such a scale by adapting the widely-used Biologische Bundesanstalt, Bundessortenamt, CHemische Industrie (BBCH) scale and its corresponding numerical code to describe stages of morphological development in M. × giganteus using observations of the "Freedom" and "Illinois" clone in Iowa, USA. Descriptive keys with images are also presented. Because M. × giganteus plants overlap in the field, the scale was first applied to individual stems and then scaled up to assess plants or communities. Of the 10 principal growth stages in the BBCH system, eight were observed in M. × giganteus. Each principal stage was subdivided into secondary stages to enable a detailed description of developmental progression. While M. × giganteus does not have seed development stages, descriptions of those stages are provided to extend the scale to other Miscanthus genotypes. We present methods to use morphological development data to assess phenology by calculating the onset, duration, and abundance of each developmental stage. This scale has potential to harmonize previously described study-specific scales and standardize results across studies. Use of the precise staging presented here should more tightly constrain estimates of developmental parameters in crop models and increase the efficacy of timing-sensitive crop management practices like pest control and harvest.

Growth and fecundity of fertile Miscanthus × giganteus ("PowerCane") compared to feral and ornamental Miscanthus sinensis in a common garden experiment: Implications for invasion.

Perennial grasses are promising candidates for bioenergy crops, but species that can escape cultivation and establish self-sustaining naturalized populations (feral) may have the potential to become invasive. Fertile Miscanthus × giganteus, known as "PowerCane," is a new potential biofuel crop. Its parent species are ornamental, non-native Miscanthus species that establish feral populations and are sometimes invasive in the USA. As a first step toward assessing the potential for "PowerCane" to become invasive, we documented its growth and fecundity relative to one of its parent species (Miscanthus sinensis) in competition with native and invasive grasses in common garden experiments located in Columbus, Ohio and Ames, Iowa, within the targeted range of biofuel cultivation. We conducted a 2-year experiment to compare growth and reproduction among three Miscanthus biotypes-"PowerCane," ornamental M. sinensis, and feral M. sinensis-at two locations. Single Miscanthus plants were subjected to competition with a native grass (Panicum virgatum), a weedy grass (Bromus inermis), or no competition. Response variables were aboveground biomass, number of shoots, basal area, and seed set. In Iowa, all Miscanthus plants died after the first winter, which was unusually cold, so no further results are reported from the Iowa site. In Ohio, we found significant differences among biotypes in growth and fecundity, as well as significant effects of competition. Interactions between these treatments were not significant. "PowerCane" performed as well or better than ornamental or feral M. sinensis in vegetative traits, but had much lower seed production, perhaps due to pollen limitation. In general, ornamental M. sinensis performed somewhat better than feral M. sinensis. Our findings suggest that feral populations of "PowerCane" could become established adjacent to biofuel production areas. Fertile Miscanthus × giganteus should be studied further to assess its potential to spread via seed production in large, sexually compatible populations.

Autumnal leaf senescence in Miscanthus × giganteus and leaf [N] differ by stand age.

Poor first winter survival in Miscanthus × giganteus has been anecdotally attributed to incomplete first autumn senescence, but these assessments never paired first-year with older M. × giganteus in side-by-side trials to separate the effect of weather from stand age. Here CO2 assimilation rate (A), photosystem II efficiency (ΦPSII), and leaf N concentration ([N]) were used to directly compare senescence in first, second, and third-year stands of M. × giganteus. Three M. × giganteus fields were planted with eight plots, one field each in 2009, 2010, and 2011. To quantify autumnal leaf senescence of plants within each stand age, photosynthetic and leaf [N] measurements were made twice weekly from early September until a killing frost. Following chilling events (daily temperature averages below 10 °C), photosynthetic rates in first year plants rebounded to a greater degree than those in second- and third-year plants. By the end of the growing season, first-year M. × giganteus had A and ΦPSII rates up to 4 times greater than third-year M. × giganteus, while leaf [N] was up to 2.4 times greater. The increased photosynthetic capability and leaf N status in first-year M. × giganteus suggests that the photosynthetic apparatus was not dismantled before a killing frost, thus potentially limiting nutrient translocation, and may explain why young M. × giganteus stands do not survive winter when older stands do. Because previous senescence research has primarily focused on annual or woody species, our results suggest that M. × giganteus may be an interesting herbaceous perennial system to investigate the interactive effects of plant ageing and nutrient status on senescence and may highlight management strategies that could potentially increase winter survival rates in first-year stands.

The acoustic effects of vowel equalization training in singers.

Vowel equalization is a technique that can be used by singers to achieve a more balanced vocal resonance, or chiaroscuro, by balancing corresponding front and back vowels, which share approximate tongue heights, and also high and low vowels by means of a more neutral or centralized lingual posture. The goal of this single group study was to quantify acoustic changes in vowels after a brief training session in vowel equalization. Fifteen young adults with amateur singing experience sang a passage and sustained isolated vowels both before and after a 15-minute training session in vowel equalization. The first two formants of the target vowels /e, i, ɑ, o, u/ were measured from microphone recordings. An analysis of variance was used to test for changes in formant values after the training session. These formant values mostly changed in a manner reflective of a more central tongue posture. For the sustained vowels, all formant changes suggested a more neutral tongue position after the training session. The vowels in the singing passage mostly changed in the expected direction, with exceptions possibly attributable to coarticulation. The changes in the vowel formants indicated that even a brief training session can result in significant changes in vowel acoustics. Further work to explore the perceptual consequences of vowel equalization is warranted.

Agronomic experiences with Miscanthus x giganteus in Illinois, USA.

Since 2002, researchers at the University of Illinois, Urbana-Champaign, Illinois, have been studying the perennial warm-season grass Miscanthus x giganteus (M. x g.) to determine its potential as a biomass feedstock. M. x g. originated in Japan and is a hybrid believed to have M. sinensis and M. sacchariflorus as its parents. Until recently, it was used as a landscape plant in the United States, but it is now the subject of research interest because of its potentially great biomass production. In central Illinois, M. x g. begins growth in April, typically reaches 2 m by the end of May, and is normally greater than 3 m by the end of September. The grass is sterile and propagated asexually using plantlets produced in tissue culture or by rhizome divisions. Following field planting, it generally takes at least three growing seasons to become fully established and reach optimal biomass production. In central Illinois, the senesced stems are harvested from early December through early March and can potentially be treated to produce ligno-cellulosic ethanol. In University of Illinois, research started in 2002. M. x g. produced an annual average of 22.0 t/ha in northern Illinois, 34.7 t/ha in central Illinois, and 35.4 t/ha in southern Illinois per year in 2004, 2005, and 2006.

Herbaceous energy crop development: recent progress and future prospects.

Oil prices and government mandates have catalyzed rapid growth of nonfossil transportation fuels in recent years, with a large focus on ethanol from energy crops, but the food crops used as first-generation energy crops today are not optimized for this purpose. We show that the theoretical efficiency of conversion of whole spectrum solar energy into biomass is 4.6-6%, depending on plant type, and the best year-long efficiencies realized are about 3%. The average leaf is as effective as the best PV solar cells in transducing solar energy to charge separation (ca. 37%). In photosynthesis, most of the energy that is lost is dissipated as heat during synthesis of biomass. Unlike photovoltaic (PV) cells this energetic cost supports the construction, maintenance, and replacement of the system, which is achieved autonomously as the plant grows and re-grows. Advances in plant genomics are being applied to plant breeding, thereby enabling rapid development of next-generation energy crops that capitalize on theoretical efficiencies while maintaining environmental and economic integrity.