Linear Plateau Research Articles

Feasibility assessment of Japan’s fertilizer reduction target: A meta-analysis and its implications for nitrogen waste

Reducing synthetic nitrogen fertilizer (SNF) use is critical for mitigating environmental nitrogen (N) pollution caused by excessive reactive nitrogen and lowering the cost of chemical N fertilizer inputs in agricultural management. In response, Japan has set a national target to reduce chemical fertilizer inputs, with a goal of 30% reduction in SNF use. To assess the feasibility of this target, we collected ca. 1700 records from domestic SNF reduction experiments and conducted a meta-analysis to examine the effects of SNF reduction on crop yield. Using a linear plateau response model of yield to SNF application in the experiments, we assumed that the conventional SNF rates used in control plots were sufficient to reach maximum yield. Our meta-analysis indicates that a 30% SNF reduction in SNF is achievable without significant yield loss on average. This reduction can be facilitated through the use of functional fertilizers and replacement of SNF with organic materials. Additionally, we evaluated changes in nitrogen waste from domestic cropland under the new national target using simple scenarios. Our results show that a 30% SNF reduction, without substituting by organic materials, would only decrease N waste by 8.8%. However, our meta-analysis finds that greater reductions in nitrogen input are possible, indicating potential for further optimization of N management, including the use of organic amendments.

Climate change induced heat and drought stress hamper climate change mitigation in German cereal production

ContextAgricultural production and climate change strongly influence each other and there are significant efforts to minimize negative impacts in both directions. In particular, breeding progress has succeeded in reducing the carbon footprint (CFP) of cereals over time. However, there is widespread certainty that climate change-related weather extremes have led to stagnation of cereal yields in many global production regions. Research questionWe assume that climate change-related yield stagnation is also evident in variety trials in Germany, which has to date only been shown for on-farm yields. Furthermore, we expect that the stagnation in yields also leads to a stagnation in the downward trend of CFP, and that heat and drought stress in particular increase the CFP of cereals. In addition, we hypothesize that the site-specific soil quality largely determines stress induced increases in CFP. MethodsWe conduct a partial life cycle assessment (LCA) with German variety trial data from 1993 to 2021 and determine the greenhouse gas emissions per unit of land (GHGL), as well as the CFP of winter wheat, winter rye, and winter barley. Further, we evaluate the time trends of yield, GHGL, and CFP using linear and quadratic plateau models. In addition, we calculate spatio-dynamic weather indices (WIs) for moderate, severe and extreme heat and drought stress. Using mixed models, we estimate the explanatory power and effect size of heat and drought WIs on the CFP. Finally, we present the spatial differences of heat and drought on the CFP at different soil qualities. ResultsWe show yield plateaus in all crops and stagnating GHGL trends, resulting in a stagnation of the downward trend of CFP, especially for rye and barley. We highlight that heat and drought increase the CFP of all crops. However, the impact of heat and drought on the CFP varies greatly with soil quality across all crops. ConclusionsWe conclude that climate change-induced weather extremes are major challenges not only for cereal production and food security but also for climate change mitigation in the agricultural sector, highlighting the importance of high-yield locations, alongside variety selection and resource-efficient management, for climate change mitigation. SignificanceThis study is the first that proves significant yield stagnation in German variety trials. Moreover, this study is the first to analyze the impact of heat and drought stress on cereal CFP, with novel results that proof that climate adaptation will become a crucial aspect of climate change mitigation in field crops.

Switchable microscale stress response of actin-vimentin composites emerges from scale-dependent interactions.

The mechanical properties of the mammalian cell regulate many cellular functions and are largely dictated by the cytoskeleton, a composite network of protein filaments, including actin, microtubules, and intermediate filaments. Interactions between these distinct filaments give rise to emergent mechanical properties that are difficult to generate synthetically, and recent studies have made great strides in advancing our understanding of the mechanical interplay between actin and microtubule filaments. While intermediate filaments play critical roles in the stress response of cells, their effect on the rheological properties of the composite cytoskeleton remains poorly understood. Here, we use optical tweezers microrheology to measure the linear viscoelastic properties and nonlinear stress response of composites of actin and vimentin with varying molar ratios of actin to vimentin. We reveal a surprising, nearly opposite effect of actin-vimentin network mechanics compared to single-component networks in the linear versus nonlinear regimes. Namely, the linear elastic plateau modulus and zero-shear viscosity are markedly reduced in composites compared to single-component networks of actin or vimentin, whereas the initial response force and stiffness are maximized in composites versus single-component networks in the nonlinear regime. While these emergent trends are indicative of distinct interactions between actin and vimentin, nonlinear stiffening and longtime stress response appear to both be dictated primarily by actin, at odds with previous bulk rheology studies. We demonstrate that these complex, scale-dependent effects arise from the varied contributions of network density, filament stiffness, non-specific interactions, and poroelasticity to the mechanical response at different spatiotemporal scales. Cells may harness this complex behavior to facilitate distinct stress responses at different scales and in response to different stimuli to allow for their hallmark multifunctionality.

Models and sufficiency interpretation for estimating critical soil test values for the Fertilizer Recommendation Support Tool

AbstractSoil test correlation determines whether a soil test can be used to predict the need for fertilization based on the critical soil test value (CSTV). Our objectives were to compare the CSTV estimated from five combinations of correlation models and yield sufficiency interpretations and to select one method for soil test correlation performed with the Fertilizer Recommendation Support Tool (FRST). Four models were fit to three datasets with strong (Mehlich‐1 K), moderate (Mehlich‐3 K), or weak (Olsen P) correlations between soil test P or K and crop relative yield. We tested the arcsine‐log calibration curve (ALCC), exponential (EXP), linear plateau (LP), and quadratic plateau (QP) models. The CSTV was defined as 95% of the maximum predicted yield for the ALCC and EXP methods, the join point for LP, and both the join point and 95% of the maximum for the QP providing five CSTV predictions. The five CSTVs ranged from 46 to 66 mg kg−1 for the Mehlich‐1 K dataset, 115 to 165 mg kg−1 for the Mehlich‐3 K dataset, and 7 to 16 mg kg−1 for the Olsen P dataset. Ten pairwise comparisons showed the estimated CSTV was numerically and sometimes statistically influenced by the model and sufficiency level interpretation. Despite differences among CSTVs, the frequency of significant yield responses above and below the predicted CSTV was generally comparable among the methods, with false‐negative errors occurring at 0%–18% of sites for a given dataset. The QP model with a CSTV at 95% of the predicted maximum was selected as the modeling approach for FRST.

Soil biological and physical measurements did not improve the predictability of corn response to phosphorus fertilization

AbstractIncluding soil health and physical measurements with traditional soil fertility measurements has the potential to improve corn (Zea mays L.) P fertilizer recommendations. The objectives for this study were to (1) evaluate the accuracy of current South Dakota corn P recommendations in predicting yield increases and (2) determine if the predictability of yield response to P fertilization improves by including selected soil biological, physical, and chemical measurements. This project was conducted in central and eastern South Dakota from 2019 to 2022 at 117 experimental sites that varied in management, landform, and soil type. A treatment of 48.9 kg P2O5‐P ha−1 was compared to a control with no P fertilizer. Soil samples (0–15 cm) collected before fertilization were analyzed for selected soil physical, chemical, and biological parameters. Analysis suggested that the current critical P value of 16 mg Olsen‐P kg−1 was still accurate as it was still within the 68% confidence interval for the linear (12–19 mg kg−1) and quadratic plateau (16–26 mg kg−1) models. Using the critical value of 16 mg Olsen‐P kg−1, we correctly predicted P responsiveness 70% of the time. The accuracy of predicting P responsiveness was not further improved by considering selected enzymes, permanganate oxidizable C, soil respiration, total C, or total N, but was improved by considering pH, soil organic matter, and apparent cation exchange capacity. Therefore, the use of typical soil fertility measurements without soil physical and biological measurements is currently the best option for predicting the responsiveness of corn to P fertilization in South Dakota.

Assessing relationships of cover crop biomass and nitrogen content to multispectral imagery

AbstractCover crops provide valuable roles in sustainable agriculture, provided they produce enough biomass. To accurately measure their services to field management, spatial estimates would be useful to producers. This study used multispectral drone imagery to produce maps of normalized difference vegetation index (NDVI), normalized difference red edge index (NDRE), and a digital surface model (DSM) of cover crop plots on sandy, Mid‐Atlantic soils. Cover crops included cereal rye (Secale cereale), mixtures of rye and crimson clover (Trifolium incarnatum), and mixtures of rye and hairy vetch (Vicia villosa). Their biomass was sampled in the spring of 2019, 2020, and 2021, dried, weighed, and analyzed for total nitrogen (N) content. Measurements of NDVI became saturated (i.e., reached a linear plateau) at 3.86 Mg biomass ha−1, NDRE at 5.72 Mg biomass ha−1, and the DSM at 5.11 Mg biomass ha−1. The measured N content became saturated at 80.9, 139.1, and 75 kg N ha−1 for NDVI, NDRE, and the DSM, respectively. Based on log transformations, NDVI was a stronger predictor of biomass and N, but not C:N. The NDRE was important for biomass, N, and C:N, while the DSM interactions with cover crop species helped predict both the N content and C:N of cover crop tissues. Accumulated growing degree days was important as an individual variable for biomass and N and as an interaction with cover crop species.

Using Data from Uniform Rate Applications for Site-Specific Nitrogen Recommendations

AbstractMuch historical yield-monitor data is from fields where a uniform rate of nitrogen was applied. A new approach is proposed using this data to get site-specific nitrogen recommendations. Bayesian methods are used to estimate a linear plateau model where only the plateau is spatially varying. The model is then illustrated by using it to make site-specific nitrogen recommendations for corn production in Mississippi. The in-sample recommendations generated by this approach return an estimated $9/acre on the example field. The long-term goal is to combine this information with other information such as remote sensing measurements.

Scale-dependent interactions enable emergent microrheological stress response of actin-vimentin composites.

The mechanical properties of the mammalian cell regulate many cellular functions and are largely dictated by the cytoskeleton, a composite network of protein filaments, including actin, microtubules, and intermediate filaments. Interactions between these distinct filaments give rise to emergent mechanical properties that are difficult to generate synthetically, and recent studies have made great strides in advancing our understanding of the mechanical interplay between actin and microtubule filaments. While intermediate filaments play critical roles in the stress response of cells, their effect on the rheological properties of the composite cytoskeleton remains poorly understood. Here, we use optical tweezers microrheology to measure the linear viscoelastic properties and nonlinear stress response of composites of actin and vimentin with varying molar ratios of actin to vimentin. We reveal a surprising, nearly opposite effect of actin-vimentin network mechanics compared to single-component networks in the linear versus nonlinear regimes. Namely, the linear elastic plateau modulus and zero-shear viscosity are markedly reduced in composites compared to single-component networks of actin or vimentin, whereas the initial response force and stiffness are maximized in composites versus single-component networks in the nonlinear regime. While these emergent trends are indicative of distinct interactions between actin and vimentin, nonlinear stiffening and long-time stress response appear to both be dictated primarily by actin, at odds with previous bulk rheology studies. We demonstrate that these complex, scale-dependent effects arise from the varied contributions of network density, filament stiffness, non-specific interactions, and poroelasticity to the mechanical response at different spatiotemporal scales. Cells may harness this complex behavior to facilitate distinct stress responses at different scales and in response to different stimuli to allow for their hallmark multifunctionality.

Responses of Crop and Soil Phosphorus Fractions to Long-Term Fertilization Regimes in a Loess Soil in Northwest China

Contrasting fertilization modifies soil phosphorus (P) transformation and bioavailability, which impact crop P uptake and P migration in the soil profile. A long-term (25-year) fertilizer experiment was employed to investigate crop yield, P uptake and changes in sequentially extracted P fractions in the soil profile, and their relationships on a calcareous soil derived from loess material under a winter wheat and summer maize double-cropping system. The experiment involved seven nutrient management treatments: control (CK, no nutrient input), N, NK, NP, and NPK, representing various combinations of synthetic nitrogen (N), phosphate (P), and potassium (K) applications, as well as combinations of NPK fertilizers with either crop residues (SNPK, where S refers to maize stalk or wheat straw) or manure (MNPK, where M refers to dairy manure). Wheat and maize yields were significantly higher with P input fertilizer relative to the P-omitted treatments. Long-term application of P-containing fertilizers markedly raised the contents of inorganic (Pi) and organic (Po) P fractions at 0–20 cm depth compared with the P-omitted treatments. Moreover, both Pi and Po fractions were markedly higher under MNPK than under NPK and SNPK treatments. For achieving high yield for wheat and maize, the critical contents of labile P were 54 and 63 mg kg−1, and those of moderately labile P were 48 and 49 mg kg−1, respectively, defined by the linear plateau model. In addition, the change points of labile P and moderately labile P were 99 and 70 mg kg−1, above which CaCl2-P content significantly increased. Moreover, long-term P input significantly accumulated different P fractions in the deeper soil layers up to 100 cm, with large portions of organic P being a composite of labile and moderately labile P, especially in MNPK treatment. Our results suggest that excessive P supply with organic manure resulted in massive P accumulation in the topsoil and promoted soil P fraction transformation and availability in the deep soil layers, especially in an organic P form that has often been neglected.

Nitrogen fertilizer and pronitridine rates for corn production in the Midwest U.S.

ContextReducing nitrogen (N) losses can be accomplished by applying recommended N rates and using nitrification inhibitors (NI). In some agricultural systems, managing N application rate or using a NI could improve N use efficiency and increase crop yields. ObjectiveThe objectives of this 13 site-year study were to determine the agronomic optimum N rate (AONR) application rate using linear plateau and quadratic plateau models, determine the optimum pronitridine rate when applied with 70 % of the recommended N amount, and evaluate the effect of nitrapyrin and pronitridine on corn (Zea mays L.) yield. MethodsIn this experiment, pronitridine and nitrapyrin were used as NIs and were applied in the fall and spring. This research was conducted in the US in Illinois (IL), Missouri (MO), and Nebraska (NE) from 2016 to 2019. ResultsThe AONR varied from 176 to 291 kg ha-1 in different site-years. The optimal pronitridine rate was predicted using the generalized additive model (GAM) for each site. A pronitridine rate of 5.6 g kg-1 N and 8.2 g kg-1 N was recommended for well drained (NE) and poorly drained (MO and IL) sites, respectively. The pronitridine application at an average rate of 5.6 g kg-1 N increased corn grain yield 4 % compared to the non-treated control. Economic analysis showed an increase in gross margin returns of 32–67 $ ha-1 in poorly drained soils (MO & IL) when applied at 8 g kg-1 with fall and spring N application. Whereas 10–30 $ ha-1 higher gross margins were observed in well-drained soils (NE) with an application of 4 g kg-1 of pronitridine for fall and spring application timings. ConclusionThe differences in AONR and pronitridine rate prediction observed in this study emphasize the variability caused by factors such as the soil, environment, and their interaction with the N cycle. When we evaluated pronitridine and nitrapyrin with all site years combined, no differences between the two NIs were observed in terms of corn yield production. SignificanceOur findings are the first to quantify corn yield response for pronitridine applications at different locations and multiple rates in the Midwest U.S. The results of this study highlight the optimum pronitridine optimum rate for improved corn yield in poorly drained and well-drained soils in the Midwest U.S. Profitability of pronitridine can be improved by applying an optimum rate based on N requirements and soil conditions.

Fully Bayesian economically optimal design for a spatially varying coefficient linear stochastic plateau model over multiple years

Fully Bayesian economically optimal design for a spatially varying coefficient linear stochastic plateau model over multiple years

Using post‐season tissue nitrogen concentrations to predict adequacy of in‐season nitrogen management

AbstractHigh‐yielding mechanized rice production requires large amounts of nitrogen (N) fertilizer, which can be particularly costly to producers when applied in excess. The development of a tissue test to detect overapplication of N to rice is needed. Nitrogen response trials arranged in a randomized complete block design were established to identify a critical concentration threshold for a tissue test to detect excess N availability. Rice stalk samples were collected from 0 to 20 cm above the soil within 5 days of harvest and analyzed for NO3−‐N concentration. Two models were fit to the data to represent rice grain yield as a function of N concentration: the linear plateau model and the quadratic plateau model. The data were well represented by both models; however, the linear plateau model more accurately described the data with a normalized root mean square error of 0.128 for linear plateau and 0.131 for quadratic plateau and a significant F‐test (p < 0.0001). The join point of the linear response region and the plateau region of the model serves as a critical value that separates the responsive (N deficient) and non‐responsive (N optimum or excessive) regions. The 95% confidence interval of the join point (2.1 mg NO3−‐N kg−1) was selected as a practical, agronomic critical concentration threshold to reduce false positive errors. The data presented here further supports the use of a post‐season tissue test in rice to detect overfertilization and establish a critical concentration threshold for this tissue test.

Need to revisit potassium soil test methods: ammonium acetate method does not correlate with tuber yield and potassium uptake in potato

The study was driven by concerns regarding lack of response to K applied as per existing soil test based fertilizer recommendations in case of the potato crop in northwest India. Geo-tagged surface soil (0-15 cm) samples 180 were collected from three (60 each) different fields (named A, B and C) followed by pot experiment involving potato planted to 30 different surface (0-15 cm) soils using two K levels (0 and 60 kg K2O ha−1). Cate-Nelson (CN) model, and non-linear segmented linear-plateau (LP) and quadratic-plateau (QP) models were used to compute critical K levels by relating relative yield with soil test K using five different methods: 1 M ammonium acetate (AA K), ammonium bicarbonate-diethylenetriamine pentaacetic acid (AB-DTPA), Mehlich-3, sodium tetraphenylboron (STPB) and 1 M boiling nitric acid. These were validated by conducting fertilizer response trials (six K fertilizer levels- 0, 15, 30, 45, 60 and 90 kg K2O ha−1) at four sites. AA K correlated with other soil K extractants in the order: AB-DTPA (r = 0.93**, 0.27* and 0.67**)> STPB K (r = 0.71**, 0.27* and 0.39**) whereas AA K generally did not show any correlation with HNO3 K. AAK method was poorly correlated with yield and plant K uptake (r = 0.15, 0.24, respectively) in comparison to AB-DTPA (r = 0.75**, 0.64**), Mehlich-3 (r = 0.78**, 0.72**), STPB (0.58**, 0.76**) and nitric acid method (0.55**, 0.44*). Thus, multi-nutrient extractants like AB-DTPA and Mehlich-3 are better (than AAK) indices of plant available K.

Coccidiosis infection and growth performance of broilers in experimental trials: insights from a meta-analysis including modulating factors

An infection by protozoa Eimeria spp. can cause coccidiosis, which negatively affects broiler chicken performance and causes economic and production losses. To understand the effect of coccidiosis on broilers' performance, we evaluated the independent variables and their interactions on the severity of coccidiosis in broilers that cause variation (Δ) of average daily feed intake (ADFI), average daily gain (ADG), and gain per feed (G:F) of broiler chicks using a meta-analysis approach. A database of 55 papers describing 63 experiments was gathered; broilers were challenged by Eimeria species (E. acervulina, E. maxima, E. tenella, and mixed) and at least 2 variables among ADFI, ADG, and feed conversion ratio (FCR) were studied. The variation induced by the challenge was calculated relative to the control group of each experiment. The indirect factors evaluated were days postinfection (DPI), Eimeria type and dose, infection age (IA), bird's mean age in the analyzed period, genetic line, sex, and whether they were raised in a cage or a pen. Graphical, correlation, and variance analyses were performed to evaluate the form of the responses. Then, a linear plateau model was adjusted for each response variable as a function of DPI to determine the consequences of the disease on the variation of performance over time after infection. The impact of the infection challenge on the variation of performance vs. nonchallenge broilers was only impacted by DPI (P < 0.05). The adjustment of the data with the linear plateau model allows us to determine the host response to the coccidiosis disease at different stages. At 5 DPI (acute phase), ΔADFI, ΔADG, ΔG:F were of -19.0; -39.8, and -25.5, respectively. After almost 13 DPI birds achieved the recovery phase for all variables with Δ varying from -19 to -3.75% for ADFI, from -39.8 to -10.5% for ADG, and from -25.5 to -7.24% for G:F. The Eimeria impact was higher in ADG than ADFI in all periods due to Eimeria aggressive action form causing lesions in gut epithelial reducing the use of nutrients and energy. The results can be used as a quantitative approach to determine the consequences of Eimeria spp. on broiler performance.

Hybrid planning techniques for early-stage left-sided breast cancer: dose distribution analysis and estimation of projected secondary cancer-relative risk

Purpose The purpose of this study was to evaluate three techniques of irradiation of left-sided breast cancer patients, three-dimensional conformal radiotherapy (3D-CRT), hybrid Intensity-Modulated Radiotherapy (h-IMRT), and hybrid Volumetric-Modulated Arc Therapy (h-VMAT, h-ARC), in terms of dose distribution in the planning target volume (PTV) and organs at risk (OARs). The second aim was to estimate the projected relative risk of radiation-induced secondary cancers for hybrid techniques. Materials and methods Three treatment plans were prepared in 3D-CRT, h-IMRT, and h-VMAT techniques for each of the 40 patients, who underwent CT simulation in deep inspiration breath-hold (DIBH). For hybrid techniques, plans were created by combining 3D-CRT and dynamic fields with an 80%/20% dose ratio for 3D-CRT and IMRT or VMAT. Cumulative dose–volume histograms were used to compare dose distributions within the PTV and OARs (heart, left anterior descending coronary artery [LAD], left and right lung [LL, RL], right breast [RB]). Projected risk ratios for secondary cancers were estimated relative to 3D-CRT using the organ equivalent dose (OED) concept for the Schneider’s linear exponential, plateau, and full mechanistic dose–response model. Results All plans fulfilled the PTV criterium: V95%≥95%. Compared to 3D-CRT, both hybrid techniques showed significantly better target coverage (PTV: V95%>98%, p < 0.001), and the best conformality was achieved by h-ARC plans (CI: 1.18 ± 0.09, p < 0.001). Compared to 3D-CRT and h-ARC, h-IMRT increased the average sum of monitor units (MU) over 129.9% (p < 0.001). H-ARC increased the mean dose of contralateral organs and the LL V5Gy parameter (p < 0.001). Both hybrid techniques significantly reduced the D max of the heart by 5 Gy. Compared to h-IMRT, h-ARC increased secondary cancer projected relative risk ratios for LL, RL, and RB by 18, 152, and 81%, respectively. Conclusions The results confirmed that both hybrid techniques provide better target quality and OARs sparing than 3D-CRT. Hybrid VMAT delivers less MU compared to hybrid IMRT but may increase the risk of radiation-induced secondary malignancies.

Determination of a critical nitrogen dilution curve and nitrogen nutrition index for maize in Western Nile Delta of Egypt

Critical nitrogen (N) dilution curves are valuable tools for diagnosing N deficiency and managing its levels in plants. The objectives of this study were to establish a critical N dilution curve for maize in Egypt’s West Delta region, assess the potential of using it to compute the N nutrition index (NNI) and compare this curve with existing curves for maize in other regions. The experiment was carried out across four site years (2020–2021), with seven N fertilization rates (0–360 kg N ha−1) used to induce variability in plant growth. Aboveground shoot biomass (W; Mg DM [dry matter] ha−1) and N concentration (Nc ; g kg−1 DM) were determined on five sampling dates during the growing season. A critical N dilution curve ( was developed, which differed moderately from those reported in France, Germany, and China. The NNI computed from this curve recognized both limited and non-limited N nutrition conditions. The findings of progressing NNI suggest that the period between V9 (9th leaf collar fully unfolded) and V12 is critical and that a sufficient supply of N fertilizer is essential. Furthermore, the NNI derived from an independent dataset, utilizing the Nc established in this study, exhibited a strong relationship with the relative grain yield. The relationship was characterized by a linear plateau function, which accounted for 74% of the observed variance. The results of this study will offer dependable guidance for detecting N levels in maize and customizing the application of precision N fertilizers to enhance yield and use efficiency.

The “solvent” effect of short arms on linear and nonlinear shear rheology of entangled asymmetric star polymers

This study examines the influence of the short arms in model asymmetric 3-arm star polymers, in which the short arm is unentangled while the other two long arms are entangled, on linear and nonlinear shear rheological behavior. As increasing the short arm length of the asymmetric star polymers, the linear viscoelastic rubber plateau decreases, indicating the relaxed short arms act as “solvent” that dilute the star polymers. This idea is examined by the relationship between the plateau moduli of polymer solutions GN(φ) and the corresponding polymer melts GN(1) for entangled linear polymers, GN(φ) = GN(1)φ1+α, where φ is the volume fraction of the polymer. The “solvent” effect of the short arms is also supported by the nonlinear rheology results showing weaker damping function and larger peak strain at stress overshoot. With the above clarification of the short-arm contributions, this work provides a guidance of molecular design for tuning linear and nonlinear rheology of star polymers.

Experimental investigation on dynamic compressive properties of SHCC after freeze-thaw cycles

In this paper, the split Hopkinson pressure bar (SHPB) test was used to investigate the variation of dynamic compressive properties of SHCC with various freeze-thaw (FT) cycles and strain rates. The full-field strain distribution and cracking characteristics of FT-damaged SHCC after the SHPB test were quantitatively and characterized by the high-speed digital image correlation (DIC) technique. The internal damage was analyzed using an X-ray CT imaging technique and SEM (Scanning electron microscope). Results show that dynamic compressive strength, energy absorption ability and dynamic increase factor (DIF) increase as the increase of strain rate, and these increase trends are weakened by the FT damage. The DIF model is established considering the number of FT cycles and strain rates. Variation of crack width in SHCC obtained through the high-speed DIC technique can be divided into three stages: linear increase stage, plateau stage and slow increase stage.

Early bone reformation after cranial vault remodelling for sagittal craniosynostosis: A retrospective 3D analysis

This study aims to measure postoperative bone reformation percentage, rates and patterns after cranial vault remodelling (CVR) in isolated non-syndromic sagittal craniosynostosis. Volumetric bone measurements were performed starting from the DICOM files of previously available postoperative CT scans. The 3D images were then resampled into the master box, and ‘Skull 3D models’ were derived. The percentage of bone reformation was investigated using automated 3D analysis software. The intra-rater reliability analysis revealed high reliability (Intraclass correlation coefficient = 0.99, p < 0.001). The median bone reformation volume and rate were 11.2 ml and 1.98 ml/week, respectively. The median percentage of bone reformation was 56.7% when the median postoperative CT timing was 6.1 weeks. As a statistic model, the linear plateau showed the highest Pseudo R2 in both volume and percentage of bone reformation predicting patterns. By using the calculated model at 9 weeks postoperatively, the re-osteogenesis reaches 80% of the total cranial defect. After CVR, the early bone reformation pattern was demonstrated as a linear plateau model rather than logarithmic. This study gives a better understanding of the pattern and quantity of re-osteogenesis at cranial defects after CVR. The statistic model can facilitate healthcare practitioners to predict bone reformation and improve postoperative care protocol in sagittal craniosynostosis management.

Using Digital Image Analysis to Estimate Corn Ear Traits in Agrotechnical Field Trials: The Case with Harvest Residues and Fertilization Regimes

In this study, we aimed to evaluate the feasibility of digital image analysis (DIA) as a substitute for standard analysis (SA) in assessing corn ear traits in agrotechnical field trials. Accurate and timely prediction of corn yield through corn ear traits can lead to precise agricultural management recommendations for the improvement of production. Four replications with 10 plots each were subjected to different fertilization regimes and analyzed using DIA and SA to determine the kernel number per ear (KN), ear length (EL), and ear diameter (ED). For both methods, the results showed that only nitrogen doses had a significant effect on the examined corn ear traits, and the correlation matrix revealed a strong and significant relationship between yield and corn ear traits. The post-hoc test showed no discrepancy in cases between the two methods for KN and EL, with a 6.7% discrepancy for ED. For both methods, a linear plateau was the best fit for KN and EL with increasing nitrogen doses, whereas a quadratic plateau was the best fit for ED. The regression equations for both methods provided similar recommendations regarding nitrogen requirements. The findings suggest that DIA can be used as a substitute for SA of corn ear traits obtained from different fertilization variants and can provide nitrogen fertilization recommendations for optimal corn yields.