Incomplete Factorial Design Research Articles

Effectiveness of a school- and primary care-based HPV vaccination intervention (the PrevHPV study)

Abstract Background HPV vaccine coverage (VC) remains lower than expected in many countries, particularly France. We developed and evaluated the PrevHPV multicomponent intervention to improve HPV VC among French adolescents. The components were ‘education and motivation’ of adolescents in schools, ‘at-school vaccination’, and ‘general practitioners’ (GPs) training’. We evaluated the effectiveness of the intervention two months after it ended. Methods We carried out a pragmatic cluster randomized controlled trial with incomplete factorial design in 14/25 French school districts (July 2021-April 2022). The cluster was the municipality (n = 91). The outcome was HPV VC (≥ 1 dose) two months after the intervention ended among 11-14-year-olds living in participating municipalities (data from the French national reimbursement database and from the trial). We performed two types of analyses: (1) without considering the dose of intervention received, using a linear model with one fixed effect per component, adjusted for baseline HPV VC; (2) a post hoc on-treatment analysis, rerunning the linear model by replacing the fixed effects with a quantitative ‘dose of intervention’ variable calculated for each component using data collected during the trial. Results For the three intervention components, estimates of the effect on VC at two months were greater for the on-treatment analyses than for the analysis that did not consider the intervention dose. For the ‘at-school vaccination’ component, the estimate increased from 5.50 percentage points (pp; p < 0.001) to 11.25 pp (p < 0.001). The ‘GPs’ training’ component reached significance (from -1.46 pp, p = 0.150 to 3.56 pp, p = 0.049). In both types of analyses, no significant effect was observed for ‘education and motivation’ (from -0.08 pp, p = 0.950 to 2.58 pp, p = 0.241). Conclusions Increasing HPV VC among adolescents requires the involvement of various stakeholders and could be achieved by combining interventions in both schools and primary care settings. Key messages • The PrevHPV study is supported by the French health authorities and conducted by a multidisciplinary consortium to tackle a long-lasting public health concern in France. • Offering free HPV vaccination at school significantly increased HPV VC; providing GPs with training and a dcision-aid tool helped increase HPV VC if the GPs completed the training.

Effectiveness of a School- and Primary Care–Based HPV Vaccination Intervention

The human papillomavirus (HPV) vaccine is safe and effective, yet vaccination coverage remains below public health objectives in many countries. To examine the effectiveness of a 3-component intervention on HPV vaccination coverage among adolescents aged 11 to 14 years 2 months after the intervention ended, each component being applied alone or in combination. A cluster randomized trial with incomplete factorial design (PrevHPV) was conducted between July 1, 2021, and April 30, 2022, in French municipalities receiving 0, 1, 2, or 3 components of the intervention. Randomization was stratified by school district and municipalities' socioeconomic level. Analyses were carried out on 11- to 14-year-old adolescents living in all participating municipalities, regardless of what had been implemented. The PrevHPV intervention had 3 components: (1) educating and motivating 11- to 14-year-old adolescents in middle schools, along with their parents; (2) training general practitioners (GPs) on up-to-date HPV information and motivational interviewing techniques; and (3) free HPV vaccination at school. The primary outcome was HPV vaccination coverage (≥1 dose) 2 months after the intervention ended among 11- to 14-year-old adolescents living in participating municipalities, based on the French national reimbursement database and data collected during the trial in groups randomized to implement at-school vaccination. A total of 91 municipalities comprising 30 739 adolescents aged 11 to 14 years (15 876 boys and 14 863 girls) were included and analyzed. Half the municipalities were in the 2 lowest socioeconomic quintiles and access to GPs was poor in more than two-thirds of the municipalities. Thirty-eight of 61 schools (62.3%) implemented actions and 26 of 45 municipalities (57.8%) had at least 1 trained GP. The median vaccination coverage increased by 4.0 percentage points (IQR, 2.0-7.3 percentage points) to 14.2 percentage points (IQR, 9.1-17.3 percentage points) at 2 months. At-school vaccination significantly increased vaccination coverage (5.50 percentage points [95% CI, 3.13-7.88 percentage points]) while no effect was observed for adolescents' education and motivation (-0.08 percentage points [95% CI, -2.54 to 2.39 percentage points]) and GPs' training (-1.46 percentage points [95% CI, -3.44 to 0.53 percentage points]). Subgroup analyses found a significant interaction between at-school vaccination and access to GPs, with a higher effect when access was poor (8.62 percentage points [95% CI, 5.37-11.86 percentage points] vs 2.13 percentage points [95% CI, -1.25 to 5.50 percentage points]; P = .007 for interaction). In this cluster randomized trial, within the context of the late COVID-19 pandemic period and limited school and GP participation, at-school HPV vaccination significantly increased vaccination coverage. The trial did not show a significant effect for training GPs and education and motivation, although it may be observed after more time has elapsed after the intervention. ClinicalTrials.gov Identifier: NCT04945655.

Potassium release behavior from silicate rocks using sulfuric and citric acids media

Potassium plays a pivotal role as a critical nutrient and essential for increasing crop productivity. Recent scientific studies have been directed toward investigating silicate minerals as a promising alternative source for this element. This study presents results derived from a preliminary exploration into the release of potassium behavior, alongside other present ions, extracted from silicate rocks originating from the region of Rio de Janeiro, Brazil. The efficacy of sulfuric and citric acids as potential agents for facilitating this release was examined. Employing an incomplete factorial design, the study systematically evaluated the influential variables temperature, time, and concentration, aiming to delineate their impact on potassium release across various sample-acid systems. The discussion delves into elucidating the hierarchical order of these variables concerning potassium liberation within each sample-acid configuration. The consequential insights derived from this meticulous analysis hold considerable significance, contributing substantially to the prospective assessment of harnessing these rocks as a viable potassium resource for future agricultural applications.

Fertilization, pruning and controlled fires on the growth of Feijoa sellowiana (O. Berg) O. Berg.

Feijoa sellowiana (O.Berg) O. Berg is an ornamental and food plant, as well as an important species for ecological restoration and landscaping that still requires much research before consolidating it in the tropical market. To understand if the implementation of techniques focusing on improving fruit production at its wild condition would affect the species’ development, we planted 216 saplings of various mother trees in an incomplete factorial block design applied in nine treatments. We tested formative aerial pruning (drastic intensity), fertilization (chemical and organic), and the effect of controlled fires prior to planting. We evaluated biomass alterations by systematically measuring the third sapling of each treatment, quantifying fresh and dry matter in two periods. We also measured changes in height (H), root collar diameter (RCD), and the H/RCD ratio. We carried out nine measurements during 27 months and used linear mixed-effects models to consolidate the long-term evaluation. Our results indicate a positive effect from the organic fertilization on the plants’ height, a momentary increase in RCD caused by programmed fires, and an increase in the H/RCD ratio due to formative aerial pruning (increasing resistance). Fertilization did not accelerate the increase in RCD and had no effect on the H/RCD ratio.

Impact of a school-based and primary care-based multicomponent intervention on HPV vaccination coverage among French adolescents: a cluster randomised controlled trial protocol (the PrevHPV study)

IntroductionVaccination is an effective and safe strategy to prevent Human papillomavirus (HPV) infection and related harms. Despite various efforts by French authorities to improve HPV vaccine coverage (VC) these past...

Managing Density Stress to Close the Maize Yield Gap.

Continued yield increases of maize (Zea mays L.) will require higher planting populations, and enhancement of other agronomic inputs could alleviate density-induced stress. Row spacing, plant population, P-S-Zn fertility, K-B fertility, N fertility, and foliar protection were evaluated for their individual and cumulative impacts on the productivity of maize in a maize-soybean [Glycine max (L.) Merr.] rotation. An incomplete factorial design with these agronomic factors in both 0.76 and 0.51 m row widths was implemented for 13 trials in Illinois, United States, from 2014 to 2018. The agronomic treatments were compared to two controls: enhanced and standard, comprising all the factors applied at the enhanced or standard level, respectively. The 0.51 m enhanced management control yielded 3.3 Mg ha–1 (1.8–4.6 Mg ha–1 across the environments) more grain (25%) than the 0.76 m standard management control, demonstrating the apparent yield gap between traditional farm practices and attainable yield through enhanced agronomic management. Narrow rows and the combination of P-S-Zn and K-B fertility were the factors that provided the most significant yield increases over the standard control. Increasing plant population from 79,000 to 109,000 plants ha–1 reduced the yield gap when all other inputs were applied at the enhanced level. However, increasing plant population alone did not increase yield when no other factors were enhanced. Some agronomic factors, such as narrow rows and availability of plant nutrition, become more critical with increasing plant population when density-induced stress is more significant. Changes in yield were dependent upon changes in kernel number. Kernel weight was the heaviest when all the management factors were applied at the enhanced level while only planting 79,000 plants ha–1. Conversely, kernel weight was the lightest when increasing population to 109,000 plants ha–1 while all other factors were applied at the standard level. The yield contribution of each factor was generally greater when applied in combination with all other enhanced factors than when added individually to the standard input system. Additionally, the full value of high-input agronomic management was only realized when matched with greater plant density.

Evaluating agronomic factors for maize production in a semi‐arid Loess Plateau

AbstractCrop production is often affected by multiple agronomic factors. However, little has been reported on the synergistic effects of multiple factors on crop production. Here, we reported the effects of five factors (i.e., variety, planting density, nitrogen application, supplemental irrigation, and plastic mulching) on crop yields, using data from a 5‐yr experiment at Dongyang, Shanxi province of China. An incomplete factorial design with these factors comprised 12 treatments, including two controls: optimized technology (OT) and conventional technology (CT), comprising all five factors applied at the added or subtracted level, respectively. The result showed that, on 5‐yr average, OT significantly increased maize yield by 3.5 Mg ha–1 (44.3% more) as compared to CT (7.9 Mg ha–1), showing a huge potential for increasing yields. Among the five factors, plastic mulching contributed the most in yield increase (11.5%), and high density, improved variety, and irrigation contributed 9.9, 6.9, and 5.1% increases in yield, respectively. There were no significant differences in yield between two N input levels (i.e., 225 and 300 kg N ha–1), suggesting the N input of 225 kg N ha–1 was sufficient to realize a yield level of 8–11 Mg ha–1 in the studied area. In conclusion, reducing the yield gap can only be achieved by optimizing multiple factors simultaneously because the effects of single measure are relatively small and inconsistent among years. The results of our study will help develop adaptive management practices for increasing crop yield stability in other semi‐arid regions.

Plasticity and flexibility in the anti-predator responses of treefrog tadpoles

Tadpoles can respond to perceived predation risk by adjusting their life history, morphology, and behavior in an adaptive way. Adaptive phenotypic plasticity can evolve by natural selection only if there is variation in reaction norms and if this variation is, at least in part, heritable. To provide insights into the evolution of adaptive phenotypic plasticity, we analyzed the environmental and parental components of variation in predator-induced life history (age and size at metamorphosis), morphology (tail depth), and behavior of Italian treefrog tadpoles (Hyla intermedia). Using an incomplete factorial design, we raised tadpoles either with or without caged predators (dragonfly larvae, gen. Aeshna) and, successively, we tested them in experimental arenas either with or without caged predators. Results provided strong evidence for an environmental effect on all three sets of characters. Tadpoles raised with caged predators (dragonfly larvae, gen. Aeshna) metamorphosed earlier (but at a similar body size) and developed deeper tails than their fullsib siblings raised without predators. In the experimental arenas, all tadpoles, independent of their experience, flexibly changed their activity and position, depending on whether the cage was empty or contained the predator. Tadpoles of the two experimental groups, however, showed different responses: those raised with predators were always less active than their predator-naive siblings and differences slightly increased in the presence of predators. Besides this strong environmental component of phenotypic variation, results provided evidence also for parental and parental-by-environment effects, which were strong on life-history, but weak on morphology and behavior. Interestingly, additive parental effects were explained mainly by dams. This supports the hypothesis that phenotypic plasticity might mainly depend on maternal effects and that it might be the expression of condition-dependent mechanisms.Significance statementAnimals, by plastically adjusting their phenotypes to the local environments, can often sensibly improve their chances of survival, suggesting the hypothesis that phenotypic plasticity evolved by natural selection. We test this hypothesis in the Italian treefrog tadpoles, by investigating the heritable variation in the plastic response to predators (dragonfly larvae). Using an incomplete factorial common-garden experiment, we showed that tadpoles raised with predators metamorphosed earlier (but at similar body size), developed deeper tails, and were less active than their siblings raised without predators. The plastic response varied among families, but variation showed a stronger maternal than paternal component. This suggests that plasticity might largely depend on epigenetic factors and be the expression of condition-dependent mechanisms.

Dissecting Bread Wheat Heterosis through the Integration of Agronomic and Physiological Traits.

Simple SummaryTo meet the challenge of feeding almost 10 billion people by 2050, wheat yield has to double by 2050. However, over the past 20 years, yield increase has slowed down and even stagnated in the main producing countries. Similar to what has been observed in maize, hybrids have been suggested as a solution to overcome yield stagnation in wheat. However, wheat heterosis, i.e., the fact that a progeny surpasses the performances of its parents, is still limited and poorly understood. To better characterize this phenomenon, we developed and phenotyped for physiological and agronomic traits 91 hybrids and their nineteen female and sixteen male parents. We showed that hybrids had a longer grain filling phase that led to bigger grains and an increased thousand kernel weight. This resulted in a better yield for 86% of hybrids compared to the average yield of their parents. In addition, hybrids appeared to be less affected by the negative correlation between protein content and yield compared to pure lines. These results shed light on the physiological bases underlying yield heterosis in wheat, paving new ways to breed for better wheat hybrids that can help to meet agriculture’s challenges.To meet the challenge of feeding almost 10 billion people by 2050, wheat yield has to double by 2050. However, over the past 20 years, yield increase has slowed down and even stagnated in the main producing countries. Following the example of maize, hybrids have been suggested as a solution to overcome yield stagnation in wheat. However, wheat heterosis is still limited and poorly understood. Gaining a better understanding of hybrid vigor holds the key to breed for better varieties. To this aim, we have developed and phenotyped for physiological and agronomic traits an incomplete factorial design consisting of 91 hybrids and their nineteen female and sixteen male parents. Monitoring the plant development with normalized difference vegetation index revealed that 89% of the hybrids including the five higher yielding hybrids had a longer grain filling phase with a delayed senescence that results in larger grain size. This average increase of 7.7% in thousand kernel weight translated to a positive mid-parent heterosis for grain yield for 86% of hybrids. In addition, hybrids displayed a positive grain protein deviation leading to a +4.7% heterosis in protein yield. These results shed light on the physiological bases underlying yield heterosis in wheat, paving new ways to breed for better wheat hybrids.

Effect of fertilizer application on winter wheat productivity under precision agriculture in Kazakhstan

Abstract. Baimuratov, A, Bastaubayeva S, Arslan M, Yeraliyeva Z. 2021. Effect of fertilizer application on winter wheat productivity under precision agriculture in Kazakhstan. Biodiversitas 22: 1558-1563. The effect of mineral fertilization of light chestnut soils of Almalybak, Kazakhstan on the three winter wheat varieties grain yields and NDVI was carried out in 2017/18, 2018/2019 as well as 2019/2020 growing seasons using precision agriculture technologies. The experiments were set up in an incomplete factorial design with rates of NPK N90P60K45, N120P90K60, and N150P120K90. Agrochemical cartograms were ordered for the substance of effectively hydrolyzable nitrogen, extractable phosphorus, and exchangeable potassium. The total variation of NDVI was from 0.62 in the minimum (Bezostaya 100 variety, 2017/18) to 0.88 in the maximum (Aliya variety, 2019/20) in the flowering phase of wheat plants. The highest index of NDVI was observed in the N150P120K90 in the three winter wheat varieties for the three seasons. Studies directed in multivariate analyses built up the connection between fertilizer application, soil fruitfulness, and grain yield. As per the genuine heterogeneity of the fields, standards were determined and differential use of the fundamental phosphorus fertilizer was completed. The yield for the winter wheat varieties varied between 5.6-5.9 t/ha for Aliya variety, 6.5-7.0 t/ha for Grom, and 6.2- 6.7 t/ha for Bezostaya 100, which presents that P120 doses were more suitable in experimental plots for winter wheat varieties. The grain yield on mineral fertilization of NPK for the studied varieties varied from 4.2 to 7.6 t/ha for Aliya variety, from 4.0 to 6.8 t/ha for the Bezostaya 100, and from 4.5 to 7.9 t/ha for Grom. The highest grain yield was observed in the N150P120K90 for three winter wheat varieties in all three seasons.

Advances in Breeding for Mixed Cropping - Incomplete Factorials and the Producer/Associate Concept.

Mixed cropping has been suggested as a resource-efficient approach to meet high produce demands while maintaining biodiversity and minimizing environmental impact. Current breeding programs do not select for enhanced general mixing ability (GMA) and neglect biological interactions within species mixtures. Clear concepts and efficient experimental designs, adapted to breeding for mixed cropping and encoded into appropriate statistical models, are lacking. Thus, a model framework for GMA and SMA (specific mixing ability) was established. Results of a simulation study showed that an incomplete factorial design combines advantages of two commonly used full factorials, and enables to estimate GMA, SMA, and their variances in a resource-efficient way. This model was extended to the Producer (Pr) and Associate (As) concept to exploit additional information based on fraction yields. It was shown that the Pr/As concept allows to characterize genotypes for their contribution to total mixture yield, and, when relating to plant traits, allows to describe biological interaction functions (BIF) in a mixed crop. Incomplete factorial designs show the potential to drastically improve genetic gain by testing an increased number of genotypes using the same amount of resources. The Pr/As concept can further be employed to maximize GMA in an informed and efficient way. The BIF of a trait can be used to optimize species ratios at harvest as well as to extend our understanding of competitive and facilitative interactions in a mixed plant community. This study provides an integrative methodological framework to promote breeding for mixed cropping.

Optimization of a Colorimetric Assay to Determine Lactate Dehydrogenase B Activity Using Design of Experiments.

Lactate dehydrogenase B (LDH-B) is overexpressed in lung and breast cancer, and it has been considered as a potential target to treat these types of cancer. Herein, we propose a straightforward incomplete factorial (IF) design composed of 12 combinations of two reaction buffers, three pH values, three salt (NaCl) concentrations, and three incubation times, which we called IF-BPST (Buffer/pH/Salt/Time), for the optimization of a colorimetric LDH-B assay in a final volume of 100 µL using 96-well plates. The assay is based on the absorbance change at ~570 nm and the color change of the reaction mixture due to the release of NADH that reacts with nitroblue tetrazolium (NBT) and phenazine methosulfate (PMS), resulting in the formation of a blue-purple formazan. The results obtained using the IF-BPST were comparable with those obtained by response surface methodology. Our work revealed that the NBT/PMS assay with some modifications can be used to measure the activity of LDH-B and other dehydrogenases in a high-throughput screening format at the early stages of drug discovery. LDH-B containing lysates cannot be assayed directly, however, due to the sensitivity of the method toward detergents. Thus, we suggest precipitating the proteins in the lysates to remove the interfering detergents, and then to dissolve the protein pellet in a suitable buffer and carry out the assay.

Growth and fluorescence rates of Mesosphaerum suaveolens (L.) Kuntze under saline stress and salicylic acid doses

Mesosphaerum suaveolens (L.) Kuntze is a species of high phytotherapeutic and aromatic potential and quite widespread in Northeastern Brazil. However, the scarcity of good quality water and the high content of salts contained in the soil and irrigation water of the semi-arid region can compromise the crop growth and yield . Therefore, this study aimed to evaluate the effect of seed treatment with salicylic acid on the growth rates and the fluorescence indexes of chlorophyll ‘a’ from M. suaveolens plants irrigated with saline waters. The experiment was conducted in a randomized complete block design with a 5 x 5 incomplete factorial design, with five electrical conductivities of the irrigation water (ECw = 0.5, 1.45, 5.00, 8.55 and 10.0 dS m-1) and five salicylic acid doses (SA = 0.0, 0.29, 1.0, 1.71 and 2.0 mM L-1), generated by the Box Central Compound matrix. The evaluated variables were the absolute and relative growth rates for stem height and diameter and the indexes of fluorescence and quantum yield of photosystem II. The salinity of the water reduces the growth and the fluorescence indexes of the plants. The seeds treatment with salicylic acid at the doses of 1.99 and 0.69 mM L-1 attenuates the damaging effect from saline stress on the absolute and relative growths for the stem diameter.

Impact of dry sludges and sludge biochar on height and dry matter of Solanum lycopersicum L.

The generation of sludge as anthropic waste is a fundamental pollution problem. However, its conversion to biochar can be an alternative to conventional fertilization for its management and use in agriculture. In this research, we evaluated the effect of the application of different doses of dry sludge (DS) and biochar of pyrolyzed sludge (PS) on the height and dry matter of a tomato (Solanum lycopersicum L.) crop and the nutrient content in the substrate. The biochar was made by rapid pyrolysis, and the substrate and the dry matter of plants were analyzed by different physical and chemical methods. An evaluation of 11 treatments was carried out in allometric measurements of plants and foliar dry matter, in three replicates with two materials (DS and PS) added to the substrate at different levels. The plant height and dry weight were evaluated using an incomplete factorial design in a completely randomized arrangement by performing statistical analysis of multivariate variance. An increase in plant height and dry weight was observed when the doses of DS and PS were increased; however, there were no statistical differences between the two materials. The amount of carbon, organic matter, and Ca concentrations in the dry leaf weight were increased with the addition of DS and PS. Likewise, the use of these materials as conditioners or amendments to agricultural soil at doses of 10-15 t ha-1 may be viable and can contribute to reducing environmental externalities through the use of these anthropic waste materials.

Economically Optimal Rate for Nutrient Application to Maize in the Semi-deciduous Forest Zone of Ghana

Low inherent nitrogen (N), phosphorus (P), and potassium (K) contents of smallholder farms limit maize grain yield. Maize grain yield response to N, P, and K mineral fertilizer application and economically optimal rates for nitrogen (EORN), phosphorus (EORP), and potassium (EORK) were evaluated on a Ferric Acrisol within the semi-deciduous forest zone of Ghana. The nutrient rates evaluated were N (0, 30, 60, 90, and 120 kg N ha−1), P (0, 30, 60, and 90 kg ha−1 P2O5), and K (0, 30, 60 and 90 kg ha−1 K2O). The treatments were arranged in a randomized complete block with three replications using an incomplete factorial design. Nutrient responses were determined using asymptotic quadratic-plus plateau functions. The best nitrogen rate for all P and K levels was 60 kg ha−1, which gave grain yield of 5 t ha−1. Nitrogen uptake, N agronomic and N recovery efficiencies peaked at 60 kg N ha−1 while N partial factor productivity declined with increasing N application rate. Cost to grain price ratios (CP) were 1.29, 1.65, and 1.65 for N, P, and K, respectively. The EORN was 61 kg ha−1, 32% less than the recommended 90 kg N ha−1 for maize production in the semi-deciduous forest zone of Ghana. Nitrogen application had the lowest CP ratio, making its application economically profitable than P and K. The findings suggest that the application of N at 61 kg N ha−1 to maize is economically profitable than at higher application rates. However, further studies should be conducted on farmers’ fields to validate the results obtained.

Revisiting hybrid breeding designs using genomic predictions: simulations highlight the superiority of incomplete factorials between segregating families over topcross designs.

Simulations showed that hybrid performances issued from an incomplete factorial between segregating families of two heterotic groups enable to calibrate genomic predictions of hybrid value more efficiently than tester-based designs. Genomic selection offers new opportunities to revisit hybrid breeding by replacing extensive phenotyping of hybrid combinations by genomic predictions. A key question remains to identify the best design to calibrate genomic prediction models. We proposed to use single-cross hybrids issued from an incomplete factorial design between segregating populations and compared this strategy with a conventional approach based on topcross evaluation. Two multiparental segregating populations of lines, each specific of one heterotic group, were simulated. Hybrids considered as training sets were generated using either (1) a parental line from the opposite group as tester or (2) following an incomplete factorial design. Different specific combining ability (SCA) proportions were simulated by considering different levels of group divergence and dominance effects for the simulated QTL. For the incomplete factorial design, for a same number of hybrids, we considered different numbers of parental lines and different contributions of lines (one to four) to calibration hybrids. We evaluated for different training set sizes prediction accuracies of new hybrids and genetic gains along three generations. At a given training set size, factorial design was as efficient (considering accuracy) as tester design in additive scenarios, but significantly outperformed tester design when SCA was present. The contribution number of each parental line to the incomplete factorial design had a small impact on accuracies. Our simulations confirmed experimental results and showed that calibrating models on hybrids between two multiparental populations is a cost-efficient way to perform genomic predictions in both groups, opening prospects for revisiting reciprocal recurrent selection schemes.

Novel Multifunctional Biosurfactant Obtained from Corn as a Stabilizing Agent for Antidandruff Formulations Based on Zn Pyrithione Powder.

The cosmetic industry provides a wide variety of shampoos to treat dandruff, containing insoluble ingredients such as Zn pyrithione. However, the solubility of this active ingredient is quite limited in both water and oil media; thus, antidandruff formulations must include a large amount of chemically synthesized stabilizing ingredients to avoid their precipitation. In this work, the stabilization of Zn pyrithione in O/W emulsions using a biosurfactant (BS) extract and Tween 80 is studied. The study includes an incomplete factorial design based on the tea tree oil/water ratio and both surfactant and biosurfactant concentrations. The formulations are characterized in terms of particle size, stability after 30 days, and solubility of Zn pyrithione. The formulation that provided the most favorable results contains Tween 80 (5%) and BS extract (2.5%), with an O/W ratio of 0.01. This provides the smallest particle size (40.5 μm), good stability after 30 days (91.0%), and the highest solubility of Zn pyrithione (59%). The results obtained enable the use of the combination of BS extract and Tween 80 as bio/surfactants of antidandruff shampoo formulations, along with another antiseptic agent such as tea tree oil. Furthermore, this is the first work where a biosurfactant is considered to be a stabilizing agent in antidandruff formulations.

Effect of resolution, reconstruction settings, and segmentation methods on the numerical calculation of saturated soil hydraulic conductivity from 3D computed tomography images

Over the last decade, computed tomography (CT) images have been used increasingly to gain a more complete understanding of the microscale parameters that control the soil processes. Images that are used for that purpose typically are subjected to a number of successive treatments. This article evaluates for a sandy-loam soil, the impact of two CT scan resolutions (26 and 54 μm), three noise reduction levels, four settings of conversion from a 32-bit to an 8-bit image and four segmentation methods (Hapca et al., 2013; Houston et al., 2013a; Schlüter et al., 2010; Otsu, 1979) in an incomplete factorial design, on the morphological metrics and on the numerical calculation of the saturated hydraulic conductivity, Ksat. The calculations reveal variations of up to two orders of magnitude of Ksat. Houston’s and Schlüter’s segmentations appear the most sensitive to the identification of gray voxels in the key throats controlling the water flow. When combined with high noise reduction levels they produce in some extreme cases disconnections of the percolating pores. Hapca’s segmentation produces more robust results. The Kozeny-Carman relation successfully predicted the saturated hydraulic conductivity when using the critical path diameter as the characteristic length, instead of the macroscopic hydraulic radius which appears too integrative to identify the extent of the variation of key throats.

Phosphorus, nitrogen and potassium nutrition on Calonectria leaf blight in eucalypt plants

AbstractCalonectria pteridis causes Calonectria leaf blight (CLB), and consequently severe defoliation in eucalypt plantations, which results in losses in wood volume. To reduce the negative impacts of this disease in eucalypt, this study aimed to assess the application of different doses and combinations of the macronutrients N, P and K on the percentage of symptomatic leaf area (SLA) and defoliation induced by the pathogen. Cuttings of a clone of Eucalyptus grandis were transplanted to pots containing soil that received different dose combinations of N, P and K, according to an incomplete factorial design. At 200 days after transplanting, leaf samples were analysed for N, P and K contents, and then, the plants were inoculated. Forty‐five days post‐inoculation, SLA and percentage of defoliation were quantified. Potassium doses above 75 mg/dm3 of soil significantly reduced SLA and defoliation. The influence of N and P on defoliation was dependent on K doses, but both reduced symptomatic leaf area. The best control of the disease, expressed by decreased defoliation and symptomatic leaf area, was achieved with leaf content of N, P and K of 9.8, 0.8 and 10.4 g per kg leaf, respectively, obtained with doses of 55, 82.5 and 143 mg/dm3of soil, respectively. Therefore, N, P and K nutrition can be a component of an integrated management programme for the control of CLB in eucalypts.

Extending the cacao (Theobroma cacao L.) gene pool with underrepresented genotypes: growth and yield traits

The narrow level of diversity of cacao varieties that are currently cultivated in West Africa has been suggested as one of the major problems to yield improvement of the crop in its major production countries. In this study, combining abilities and heritability for growth and yield traits in 12 underrepresented cacao parents of diverse genetic groups were estimated using these as females in crosses with three tester parents. Progenies obtained from a North Carolina II (NC II) incomplete factorial mating design together with three standard varieties were evaluated in a randomized complete block design with four replications at two contrasting locations for three growth traits (percentage survival, trunk cross-sectional area in the juvenile stage (TCSAj), and jorquette height) and four yield traits (bean weight, number of beans per pod, bean yield, and yield efficiency). Mean performance of the progenies was significant (p < 0.05) for all the traits involved and progenies of some specific crosses performed better than the best standard variety. The female GCA, male GCA, and SCA male × female interaction effects were significant, which suggest that both additive and dominant effects are important in the inheritance of traits. Heritability was moderate to high (H2 = 0.35–0.70) for broad sense and low (h2ns = 0.17–0.30) for narrow sense. This indicates that even though the expression of traits is controlled by genes, it may partly be influenced by the environment. Parental clones A1/197 and DOM 3 which had significant positive GCA effect consistently produced progenies with high SCA values for most of the traits. Results from the study indicate that the underrepresented cacao clones represent a suitable genetic resource for broadening parental clones of current cacao varieties cultivated in Ghana and beyond.