LAI estimation through remotely sensed NDVI following hail defoliation in maize (Zea mays L.) using Sentinel-2 and UAV imagery.

Extreme events such as hailstorms are a cause for concern in agriculture, leading to both economic and food supply losses. Traditional damage estimation techniques have recently been called into question since damages have rarely been quantified at the large-field scale. Damage-estimation methods used by field inspectors are complex and sometimes subjective and hardly account for damage spatial variability. In this work, a normalized difference vegetation index (NDVI)-based parametric method was applied using both unmanned aerial vehicles (UAV) and Sentinel-2 sensors to estimate the leaf area index (LAI) of maize (Zea mays L.) resulting from simulated hail damage. These methods were then compared to the LAI values generated from the Sentinel-2 Biophysical Processor. A two-year experiment (2020-2021) was conducted during the maize cropping season, with hail events simulated during a range of maize developmental stages (the 8th-leaf, flowering, milky and dough stages) using a 0-40% defoliation gradient of damage intensities performed with the aid of specifically designed prototype machines. The results showed that both sensors were able to accurately estimate LAI in a nonstandard damaged canopy while requiring only the calibration of the extinction coefficient k(ϑ) in the case of parametric estimations. In this case, the calibration was performed using 2020 data, providing k(ϑ) values of 0.59 for Sentinel-2 and 0.37 for the UAV sensor. The validation was performed on 2021 data, and showed that the UAV sensor had the best accuracy (R2 of 0.86, root-mean-square error (RMSE) of 0.71). The k(ϑ) value proved to be sensor-specific, accounting for the NDVI retrieval differences likely caused by the different spatial operational scales of the two sensors. NDVI proved effective in parametrically estimating maize LAI under damaged canopy conditions at different defoliation degrees. The parametric method matched the Sentinel-2 biophysical process-generated LAI well, leading to less underestimations and more accurate LAI retrieval. Supplementary Information: The online version contains supplementary material available at 10.1007/s11119-023-09993-9.

Protein Maps for Durum Wheat Precision Harvest and Pasta Production.

The quality traits of dough and dry pasta obtained from semolina (Triticum durum Desf. var. Biensur), harvested from a 13.6 ha field, subjected to variable-rate nitrogen (N) fertilization, were assessed to test site-specific pasta production for a short supply chain. Based on the grain quality spatial distribution, two distinct areas with protein content lower or higher than 13% were delineated and harvested selectively. The rheological properties of semolina samples obtained from those areas were evaluated. Furthermore, dry pasta was produced and characterized for its cooking behaviour and sensory characteristics. Semolina was demonstrated to have rheological characteristics (i.e., gluten aggregation time and energy, as evaluated by GlutoPeak test) positively related to the protein content as well as the related pasta, showing better cooking quality. These results are driven by the high amounts of gluten proteins, as well as by the glutenin/gliadin ratio, which are indicators of the technological quality of semolina. Overall, the results indicate that segregation of the grain with >13% of protein at harvest led to the production of semolina with a higher gluten protein content and a higher glutenin/gliadin ratio and, hence, to the production of pasta with better cooking quality. Therefore, site-specific pasta could be a potential asset for a short supply chain, aiming at improving traceability, as well as environmental and economic sustainability.

Trade-offs among ecosystem services advance the case for improved spatial targeting of agri-environmental measures.

Agri-environmental measures (AEMs) are meant to foster environmentally-friendly farming techniques. The use of AEMs to enhance agroecosystem quality is still under debate due to site-specific spatial mismatches that often occur between adopted AEMs and delivered ecosystem services. Here, a site-specific approach was employed to assess the advantages and disadvantages of AEMs adopted from the Rural Development Programme and applied in the Veneto Region (NE Italy) during 2014-2020. Specifically, a DayCent model-GIS platform compared business-as-usual (BAU) and AEM scenarios. The effect of AEMs on ecosystem services was assessed by integrating high-resolution spatial data from multiple pedo-climates and land managements and combined agronomic and environmental outcomes. Results showed that AEM adoption generally improved ecosystem service delivery, especially by reducing water pollution and increasing soil fertility. Among simulated practices, permanent soil cover and minimum soil disturbance (i.e., conservation agriculture, pasture and meadow maintenance) produced the best results across the Veneto Region, despite compromises in agronomic performance due to AEM-specific commitments (e.g., narrow crop rotation in conservation agriculture, fertilizer use restrictions in pastures and meadows). Other AEMs (e.g., organic farming) appeared highly dependent on their spatial distribution and were influenced by a strong interaction between pedo-climatic characteristics (e.g., soil properties) and management techniques (e.g., type and quantity of nutrients input). The spatial-target approach is highly recommended to identify AEMs that achieve environmental quality objectives and develop indications as to where they should be encouraged to maximize ecosystem services delivery.

Changes in classic and alternative pathways of bile acid synthesis in chronic liver disease.

BACKGROUND: Cholesterol elimination occurs through bile acid synthesis that starts within the liver from 7alpha-hydroxylation or in extrahepatic tissues from 27-hydroxylation. This study was aimed at investigating in vivo these two pathways in patients with chronic liver disease. METHODS: Serum concentrations of 7alpha- and 27-hydroxycholesterol were measured in 54 patients (29 with primary biliary cirrhosis and 25 with chronic hepatitis C) and 18 controls. The rate of oxysterol plasma appearance was calculated after intravenous infusions of deuterated 7alpha- and 27-hydroxycholesterol in patients (n=8) and control subjects (n=8) who gave consent. The expression of sterol 27-hydroxylase was evaluated in macrophages isolated from 20 subjects. RESULTS: In patients with liver disease, the rate of plasma appearance of 7alpha-hydroxycholesterol was significantly reduced (1.44+/-0.96 vs. 2.75+/-1.43 mg/hour, p=0.03), the degree of reduction being related with the severity of the disease (p=0.01) whereas that of 27-hydroxycholesterol was unaffected. The rate of plasma appearance of 27-hydroxycholesterol was significantly related to its serum concentrations (r=0.54, p=0.03) and to its release from cultured macrophages ( r=0.85, p=0.03). CONCLUSIONS: In liver disease 7alpha-hydroxylation of cholesterol seems to be impaired while 27-hydroxylation is unaffected. Serum concentrations of 27-hydroxycholesterol are useful to obtain information on the activity of this alternative pathway.

A minimally invasive technique for the evaluation of the regulatory steps of the two major pathways of bile acid synthesis.

BACKGROUND: Bile acid synthesis accounts for more than 95% of total cholesterol catabolism per day. We have developed a minimally invasive technique in humans that quantifies the rates of plasma appearance of 7alpha- and 27-hydroxycholesterol, representing the first steps of the "classical" and "alternative" pathways of bile acid synthesis, respectively. METHODS: For this purpose, during the intravenous infusion of synthetic deuterated isotopomers of 7alpha-hydroxycholesterol and 27-hydroxycholesterol plasma samples are collected and analysed by a GC-MS based method that allows to quantify the exogenous/natural isotopomer ratio of the two sterols. From this data, the rates of plasma appearance of 7alpha- and 27-hydroxycholesterol are calculated. RESULTS: In a group of healthy individuals steady state kinetics are obtained during a 2 h period yielding mean values of 2.0+/-0.8 and 3.7+/-0.6 mg/h for 7alpha- and 27-hydroxycholesterol, respectively. The data are consistent with findings using older techniques that require studies over several days. CONCLUSION: Considering that at steady state of the exogenous/natural isotopomer ratio the plasma appearance of the two regulatory hydroxysterols are related to the rate of bile acid synthesis via the "classical" and the "alternative" pathways, respectively, the proposed method could be used to evaluate the immediate effects of different diets and drugs and other determinants on cholesterol catabolism.

Hyperlipidemia in Chronic Cholestatic Liver Disease.

Hyperlipidemia with a marked increase of low-density lipoprotein (LDL) and high- density lipoprotein (HDL) cholesterol levels is a common feature in patients with chronic cholestatic liver disease. Excess morbidity and mortality from cardiovascular disease has not been reported in these patients. This may be due to the particular lipoprotein pattern observed during chronic cholestasis, characterized by elevated serum HDL cholesterol, which may have a cardioprotective effect. However, in a subgroup of patients with chronic cholestasis, hyperlipidemia is characterized by markedly elevated LDL levels with normal or low HDL levels, probably reflecting hypercholesterolemia with coexisting familial and nutritional origins. Ursodeoxycholic acid, the only drug approved for the treatment of chronic cholestatic liver diseases, has been shown to slightly decrease serum cholesterol concentrations. However, the extent of LDL reduction by ursodeoxycholic acid may be insufficient to protect this subgroup of patients from increased cardiovascular risk. Patients in this subgroup probably would benefit from dietary modification, weight loss, and the administration of specific lipid-lowering drugs. Cholestyramine, which is the first-line treatment for pruritus in chronic cholestasis, may be also indicated for its cholesterol-lowering capacity in patients with hypercholesterolemia who complain of pruritus. Administration of 3-hydroxy-3-methylglutaryl coenzyme A (HMG CoA) reductase inhibitors (simvastatin or pravastatin, 20 mg/d) should be limited to hypercholesterolemic patients with mild chronic cholestatic liver diseases in whom HDL serum levels are below the protective range or if additional risk factors for cardiovascular diseases are present.