bluuebunny/crossref_metadata_2025 huggingface dataset:
AUVANA: An Automated Video Analysis Tool for Visual Complexity
Authors: Alghamdi Emad , Velloso Eduardo , Gruba Paul
Published: May 2021

Visual complexity is widely considered to be an important variable underlying visual perception. While videos have become versatile in their use of visual imagery, surprisingly, little research has been devoted to understanding the impact of visual complexity. In this paper, we present Automated Video Analysis (AUVANA) software, an open-source tool for extracting, computing, and visualizing visual complexity in digital videos. Through leveraging more sophisticated computer vision and video processing algorithms, AUVANA automatically extracts and computes 78 video visual complexity indices. Results of explanatory analyses demonstrated that rather than a unitary construct video visual complexity is more likely a multidimensional and multifaceted phenomenon. We conclude the paper with a discussion about the potential applications of the software
SciMathデータベースプロジェクト：ベトナム数学の八十年間
Authors: Le Tam-Tri , Huyen Nguyen Thanh Thanh
Published: May 2021

「ベトナム数学研究発展の８０年間・SciMathデータによる数学者と作品の概観」という報告書についてである。
Friend, Not Foe: Unveiling the Vector-Bacteria Symbiosis and its Utility as an Arboviral Intervention Strategy in the Philippines
Authors: Kee Shaira Limson , Tan Myles Joshua
Published: May 2021

Humans have long studied the ecological symbiosis of organisms primarily from an anthropocentric perspective. Among these investigations are the symbiosis of bacteria and arthropods. Studies conducted in relation to this usually lean toward subjects of pathogen transmission, cure, and prevention. But Bourtzis and Zchori-Fein, editors of Manipulative Tenants: Bacteria Associated with Arthropods, relay information about the diversity of symbiosis that occurs between bacteria and arthropods and explain that despite common negative associations between them, microbial interaction with its vector can also benefit eukaryotic organisms, including humans. In fact, some symbiotic relationships that involve bacteria are essential to the survival of arthropods. One major benefit that this relationship offers to increase survival of humans is its purpose as a biocontrol strategy aimed toward minimizing arboviruses. This poses a crucial benefit as the alarming trend of insecticide-resistant mosquitoes increase due to gradual adaptation to conventional control measures. Further research into symbiosis will greatly benefit countries like the Philippines whose commonly applied intervention strategy for dengue involves the use of insecticides and manual elimination of mosquito breeding sites.
What you net depends on if you grab: A meta-analysis of sampling method's impact on measured aquatic microplastic concentration
Authors: Watkins Lisa , Sullivan Patrick , Walter M.
Published: May 2021

Microplastic pollution is measured with a variety of sampling methods. Field experiments indicate that commonly used sampling methods, including net, pump and grab samples, do not always result in equivalent measured concentration. We investigate the comparability of these methods through a meta-analysis of over one hundred surface water microplastic studies. We find systematic relationships between measured concentration and sampled volume, method of collection, mesh size used for filtration, and water body sampled. Most significantly, a strong log-linear relationship exists between sample volume and measured concentration, with small-volume grab samples measuring up to 10^4 particles/L higher concentrations than larger volume net samples, even when sampled concurrently. Potential biases explored included filtration size (±10^2 particles/L), net volume overestimation (±10^1 particles/L), fiber loss through net mesh (unknown magnitude), and intersample variability (±10^1 particles/L). Contamination is the one potential bias with an effect large enough (±10^3 particles/L) to explain the observed differences. Based on these results, we caution the practice of comparing concentrations across multiple studies or combining multiple study results to identify regional patterns. Additionally, we reiterate previous recommendations emphasizing the importance of contamination reduction strategies, namely that blank samples be collected, tested, and reported as a matter of course for such studies.
SILR: A New Exact Test for Demonstrating That an Effect Exists in Binary Trials
Authors: Darlington Richard B. , Zhou Zhengze
Published: May 2021

Suppose N experimental participants each undergo t binary trials, and you want to show that at least some of the participants have higher success rates than would be expected if the true success rate for all participants on all trials were the same known value pnull. Under broad circumstances, a new test called SILR has substantially higher power than six other tests that might be used for this purpose. In one example, SILR yielded a significance level of 0.0032 while the other six tests all yielded values above 0.05. In one power analysis, SILR’s power exceeded that of the standard binomial test, applied to the results of all trials for all participants, even when the sample size for SILR was less than 30% that for the binomial.We provide a free R program for SILR. It can also find confidence limits on the number of experimental participants whose true hit rate exceeds the null value, and on the highest and lowest true hit rates of any participants. SILR does not show conclusively that any particular participant’s true hit rate differs significantly from the null rate. If such tests are desired, that can be done with Bonferroni-corrected binomial tests on individual participants. But SILR often has much higher power than these tests.
Psychological interventions of virtual gamification as a motivational basis: A mixed-method systematic review
Authors: Xu Joy , Lio Aaron , Dhaliwal Harshdeep , Andrei Sorina , Balakrishnan Shakthika , Nagani Uzhma , Samadder Sudipta
Published: May 2021

BACKGROUNDStudents constantly seek ways to improve productivity within academia. With the advancement of technology in the recent decade, virtual implementations may provide additional support for student productivity, particularly during the COVID-19 pandemic with online learning. One of the virtual realms for motivation include gamification, which has potential as an effective tool to further bolster an individual’s source of intrinsic motivation. METHODUsing a convergent integrated synthesis approach, qualitative and quantitative studies were extracted from APA PsycInfo, ProQuest, and IEEE for relevance to virtual gamification and intrinsic motivation. Studies were reviewed based on a pre-determined and piloted screening tool. Included studies were published between 1990 and 2020 in English within Asia, North America, and/or Europe. Only systematic reviews, randomized control trials (RCTs), metaanalysis, and grey literature were included. Study screening, extraction, and quality appraisals using the Mixed Methods Appraisal Tool (MMAT) were performed independently among two authors. Disagreements following reconciliation between two authors were settled by a third author. Heterogeneity in study designs, outcomes, and measurements precluded meta and statistical analyses; thus, a qualitative analysis of studies was provided. RESULTSBased on the appraised articles, gamification improves intrinsic motivation through badges, social interactions, points, and leaderboards. Experimental studies also displayed a correlation between learning behaviour. CONCLUSIONThe data exhibited an increase in intrinsic motivation due to gamification features, which can be integrated within a virtual context to enhance motivation with potential for application towards online learning settings.
Interventional procrastination strategies for young adults in virtual settings: A systematic review
Authors: Xu Joy , Marjia Muntaha , Ahluwalia Kundan , Zada Dana Kukje , Tavakolizaeh Nazgol , Dao Margaret
Published: May 2021

BACKGROUNDThe phenomenon of academic procrastination affects nearly 95% of post-secondary students within academia with its association seen in reduced academic performance. Amidst the onset of COVID-19, this systematic review aims to provide insight towards potential virtual interventions to support personal management of academic procrastination for young adults. METHODSThe selection procedure followed the Preferred Reporting Items for Systematic Review and MetaAnalyses (PRISMA) guidelines. The protocol was registered with PROSPERO (record ID: CRD42021234243). Studies were reviewed based on a pre-determined and piloted screening tool with study screening and extraction performed independently among two authors. After reconciliation, disagreements were settled by a third author. Study quality was assessed using the Mixed Methods Appraisal Tool (MMAT) in duplicate. Heterogeneity in study designs, outcomes, and measurements precluded meta and statistical analyses; thus, a qualitative analysis of studies was provided. RESULTSA total of 49 studies were included with identification of two primary web-based interventions for reducing academic procrastination in a mobile app setting. The first intervention involves emotional management through increasing tolerance and modifying negative emotions which determines the activity with the highest likelihood of procrastination each day, and the subject's resilience or the subject's commitment should be emphasized. The second intervention involves mental imagery for subjects to feel an affinity for his/her future self, and thus decrease procrastination behaviours. CONCLUSIONTwo main virtual interventions were determined from the systematic review: (1) an intervention for managing personal emotions, and (2) an intervention that involves creating a mental image of one's future self.
Genes, Psychology and Population History
Authors: Richardson Ken
Published: May 2021

Genome wide association studies (GWAS) are being increasingly used to identify genetic markers of variation in complex traits such as intelligence and education. However, GWAS are compromised by population stratification (PS) leading to spurious associations, and attempts to correct for them statistically are also proving to be inadequate. This suggests the need for a deeper understanding of the sources of such PS and how its roots in complex social and historical dynamics can seriously mislead interpretations from GWAS/PGS to social policy.
MINYAK MASOYI SEBAGAI ANTIBIOFILM
Authors: Hamzah Hasyrul
Published: May 2021

Penyakit infeksi masih merupakan penyebab utama morbiditas dan mortalitas di dunia. Disamping itu penyakit infeksi bertanggung jawab pada penurunan kualitas hidup jutaan penduduk di berbagai negara maju dan berkembang. Menurut WHO, sepertiga dari 25 juta kematian di seluruh dunia pada tahun 2011, disebabkan oleh penyakit infeksi. Penyakit infeksi adalah penyakit yang disebabkan oleh mikroba patogen, dan bersifat sangat dinamis. Secara umum proses terjadinya penyakit melibatkan tiga faktor yang saling berinteraksi yaitu : faktor penyebab penyakit (agen), faktor manusia atau pejamu (inang), dan faktor lingkungan (Septiari, 2012). Infeksi dapat terjadi di masyarakat maupun di rumah sakit (Wahjono, 2007). Biofilm saat ini diakui sebagai mediator utama infeksi dengan perkiraan 80% kejadian infeksi berkaitan dengan pembentukan biofilm (Archer dkk., 2011). Biofilm sebagai bagian dari pertahanan bakteri relatif lebih sulit diberantas dengan antibiotik. Dengan demikian bakteri patogen dalam bentuk biofilmnya dapat menimbulkan masalah serius bagi kesehatan manusia (Jin-Hyung Lee dkk., 2013).
Corn stover harvest strategy effects on grain yield and soil quality indicators
Authors: Karlen Douglas L. , Birrell Stuart J. , Wirt Adam R. , Schock Nathan
Published: May 2021

The development of technologies to use cellulosic biomass as a feedstock for biofuel production was recognized as an important research focus because cellulose is a more widely-available feedstock than corn starch. Our objective was to compare various corn (Zea mays L.) stover harvest strategies to determine which would be most sustainable. A complete block design with 2 ha plots, each replicated three times, was imposed on a 50 ha (125 acre) Clarion-Nicollet-Webster soil Association site near Emmetsburg, Iowa, U.S.A. before harvesting the 2008 corn crop. Hand samples were collected from a 1.5 m2 area in each plot to establish the potential amount of above-ground biomass that could be potentially harvested using one of seven stover harvest strategies. Surface soil samples (0 to 15 cm) were analyzed following each harvest to monitor fertility changes and to make subsequent fertilizer recommendations. Grain yields averaged 11.4, 10.1, 9.7, and 9.5 Mg ha-1 in 2008, 2009, 2010, and 2011, respectively, but were not signiﬁ cantly affected by stover harvest treatments. Relative yield for the various treatments ranged from 97 to 107% of the conventional treatment for which none of the residue was harvested. Four-year average stover yields ranged 1.0 to 5.2 Mg ha-1 which was 12 to 60% of the above-ground biomass. Three years of plant tissue data at anthesis indicated N management needed to be improved as the values were below the critical concentration of 27 g kg-1. Sulfur concentrations were just barely above the critical value of 15 g kg-1. Soil test analyses showed substantial ﬁ eld variability but no signiﬁ cant stover harvest treatment effects. There was a slight decrease in soil organic carbon, unrelated to the stover harvest treatments, that is attributed to the intensity of tillage and crop yields that were lower than expected. Overall, this study is consistent with other studies in the U.S. Corn/Soybean Belt that indicate to sustain soil resources within this region, corn stover should generally not be harvested if average grain yields are less than 11 Mg ha-1 (175 bu ac-1). Strategies for achieving those levels include implementing more rigorous soil-testing and plant analysis programs, installing tile drainage where needed, improving overall nutrient management programs, reducing tillage intensity, incorporating cover crops and rotating corn with other crop such as soybean [Glycine max (L.) Merr.], small grain, or forage.
Soil productivity from the sandy pampas region under the present agricultural conditions
Authors: Díaz-Zorita Martín
Published: May 2021

During the last decade, major changes in the organization, extension and intensifi cation of the agricultural systems from the sandy pampas region are observed. Crop production is mostly performed under continuous zero tillage and with the application of fertilizers. In this region, strong relationships between crop yields and soil properties, mostly related to water and nutrient storage, have been described. The purpose of this presentation is to discuss, supported by specifi c local long-term fi eld trials, about several of the changes in the productivity of the soils of the region under the present management practices. Soil organic matter levels decrease under continuous tillage practices after systems with pastures. But, the application of zero tillage practices contributed to maintain the original soil productivity properties. Production systems established on degraded soils frequently show less water use effi ciency, mainly when are cropped with maize (Zea mays L.). The establishment of continuous fertilization programs based on the suffi ciency for low mobility nutrients (e.g. Phosphorus) shows reduction in the soil extractable levels of the nutrient and lower mean crop production compared with maintenance fertilization programs. The use of winter cover crops in soybean [Glycine max (L.) Merrill] monoculture enhances physical soil properties without benefi ts on crop yields. The crop and soil management practices widely performed during this period have contributed to the soil conservation and to the water use effi ciency. However, the application of suffi ciency fertilization programs could conduct to the reduction in the levels of soil extractable nutrients and in crop productivity. The present agricultural land use in the region requires to intensify in the use of indexes for the diagnosis of soils productivity independently of the actual relationships with today`s yields. The delimitation of homogeneous areas for the application of effi cient soil management practices is needed for the conservation and enhancement of soils productivity capability.
Challenges of weeding operation in intercropping and mixed cropping systems in Nigeria
Authors: Olaoye J. O.
Published: May 2021

A literature study was undertaken on the challenges of weeding operation in intercropping and mixed cropping systems in Nigeria. Nigeria intercrops required 29% more labour input during the peak weeding period than did sole crops. Suppression of weeds in intercropping may have a benefi cial effect on crop yield and are useful in improved farming systems. The practice of growing several crops on the same piece of land is an ancient strategy for crop production among farmers in the tropics. Mixed cropping is to meet the desire of the farmer to minimize risk. This system offers the farmers insurance against total crop failure, It helps to control soil erosion and weeds, and it brings about a more even distribution of farm labour than in sole cropping. It has also been shown that diverse plant communities are more resistant to environmental stresses such as drought. Weeding is the most taxing job, both in energy and time, and traditionally, it involves bending down and working carefully not to damage the crop and at the same time, the operation must fi nished before weeds outgrow the crops. Weeding is conducted by pulling out the weeds and shaking them off. The paper highlights the challenges of application of a rotary mechanical weeding device in control of weed in intercropping farming systems and sparsely application of herbicide in traditional mixed cropping systems. The merit of mixed cropping system was identifi ed to indicate that the diverse crop species grown together to complement one another by using resources in different ways, scarce labour is effi ciently utilized, weeds and insects are suppressed, erosion is controlled and there is sequential harvesting and the risk of total crop loss is averted.
Development of a soil test for determining the impact of soil disturbance
Authors: Torbert H. A. , Gebhart D. L.
Published: May 2021

United States Federal law requires land-managing agencies like the US Army to identify and take into account the impacts of their undertakings on archaeological resources. Development of a method that uses changes in the stratification of horizon interfaces to identify the onset of adverse impacts to archaeological deposits was investigated. This method will allow Cultural resource managers to identify types and levels of military training that risk adverse impacts to intact archaeological deposits. A study was initiated at Fort Benning, GA, and Fort Riley, KS with treatments including (1) archaeological habitation/no-training, (2) archaeological habitation/training, (3) non-habitation/no-training, and (4) non-habitation/training. Soil core samples for each treatment group were taken for 0-10, 10-20, 20-30, 30-50 cm increments for chemical analysis. Several promising elements were identified that may be useful as indicators for determining potential damage to archaeological deposits resulting from ground disturbing activities such as mechanized maneuver training. Differences between disturbed and undisturbed treatment groups were often evident at depths of 20-40 cm, indicating substantial soil inversion, displacement, or mixing. Soil C concentrations were always negatively impacted in disturbed treatment group soils, indicating that C might also be a reliable indicator of disturbance, especially when used in a ratio with another elements that accumulate in undisturbed surface soil horizons. Analyses of ratios, including the Top-to-Total (ratio of upper 10 cm to entire 50 cm profile), the Total-to-Soluble (ratio of total elemental to soluble elemental concentration), and the Leachable to Non-Leachable (ratio of leachable/mobile element to a nonleachable/ immobile element) indicated promising results.
Groundwater recharge under compacted agriculturalsoils, pineand prairie in Central Wisconsin, USA
Authors: Radatz A. M. , Lowery B. , Bland W. L. , Hartemink A. E.
Published: May 2021

The water table in Wisconsin Central Sand Plain (CSP) dropped 1.8 m between 2002 and 2010, and several lakes in the area suffer from low water levels. The lower groundwater level has been attributed to agricultural cropping practices, specifically irrigation, and a reduction in ground-water recharge. Dominant soils in this area are sands (Udipsamments). The objective of our research was to quantify groundwater recharge under (i) irrigated agricultural crops, (ii) prairie, and (iii) a 50-year old pine tree plantation in the CSP. Equipment was installed at five sites to monitor water table elevation, soil water content, and precipitation at 15-minute intervals. It was found that, when the soil was at field moisture capacity, precipitation during the growing season resulted in 1.4 cm more water table rise under a prairie than under irrigated agricultural fields. Agricultural crops used groundwater through irrigation, but natural vegetation relied on soil available water, and capillary rise of water from the shallow groundwater table (1 to 2 m to water table), for daily transpiration. After snowmelt, prairie vegetation yielded greater rise, up to 16 cm, in the water table than agricultural fields. Lack of crop residue on the soil surface of agricultural fields resulted in a continuous layer of frost in the soil profile that extended to about a meter depth. This thick, frozen layer was enhanced by greater soil compaction under irrigated crops compared to limited or no compaction in prairie areas. The key finding was that this deep frost in the soil profile inhibited snowmelt water from infiltrating and recharging the groundwater. Thus, compacted-irrigated agricultural soils in the CSP alter groundwater recharge characteristics during frozen and non-frozen ground periods. Increased crop residues on the surface of agricultural fields might enhance groundwater recharge during winter snow melt periods.
A study of the contribution of cover crops to nitrogen supply for corn
Authors: Fernández R. , Saks M. , Uhaldegaray M. , Quiroga A. , Noellemeyer E.
Published: May 2021

Cover crops (CC) can provide protection from erosion and prevent soil carbon depletion. In many cases CC are fertilized to improve carbon inputs and soil cover, however there are few studies on the residual effect of nitrogen (N) in CC biomass and its contribution to N availability of subsequent crops. In order to elucidate this question, a field experiment with rye as cover crop during fallow for corn was carried out at INTA experimental station Anguil, La Pampa. The four treatments were control (C), and CC fertilized with 0, 40 and 80 kg N ha-1 (N0, N40 and N80), in a completely randomized block design. The fertilized CC treatments were later split at V6 of the corn crop, with applications of 60 and 120 kg N ha-1 for N40 and N80 respectively (N40+60 and N80+120). Dry matter (DM) and nutrient contents of standing CC and their residues was determined at “drying” of CC, planting and harvest of corn. Corn yields were recorded at maturity. Fertilized CC had significantly higher DM and N contents than N0 throughout the sampling period; loss of N from CC residues was 38.1, 43.6, 50.2 kg ha-1 for N0, N40 and N80 respectively, around 90% of this loss occurred between “drying” and planting. Assuming the total N loss from DM, this represented 40, 35 and 22% of total corn N uptake for N0, N40 and N80. The yield response of corn to N40 and N80 was 1.5 and 6.1 Mg ha-1, resulting in N use efficiencies of 0.3 and 0.12 Mg grain per kg N applied, respectively. Fertilizer applied to corn caused yield increases of 5.0 and 1.9 Mg for N40+60 and N80+120, with efficiencies of 0.08 and 0.01 Mg grain per kg N applied, respectively. We concluded that N applied to cover crops could be an efficient practice to enhance N availability for corn.
Evaluation of different tillage intensities on Eucalyptus grandis on a typic hapludult of Uruguay
Authors: González P. , Pérez Bidegain M. , Gutiérrez L. , Martinez L. , García Préchac F.
Published: May 2021

Planting and harvesting time are the most critical moments in terms of soil erosion risk in commercial forest plantations. Soil tillage systems that reduce soil removal while maintaining wood productivity are necessary. The objective of this research was to evaluate the effect of different site preparation methods on Eucalyptus grandis wood productivity 10 years after plantation. The experimental site was located on a Typic Hapludult in the department of Rivera, Uruguay. A randomized complete block design with three replicates was established. Treatments included: furrower on the plantation row, and mechanical weed control (disk-harrow) in the inter-row area (T1); idem to T1 but substituting interrow mechanical control by herbicide control (glyphosate) (T2); pit-planting (T3); rotavator on the plantation row and inter-row weed control idem to T1 (T4); and T5 idem to T4 but herbicide control in the inter-row area. Tree height (Ht) and diameter breath height (DBH) was measured 5 times after thinning in the experimental period (21, 38, 58, 98 and 120 months after plantation) and DBH and wood production(WP) data were analyzed with repeated measures in time, where the subject was the plot and the autocorrelation structure selected was antedependence (ANTE(1)). Significant differences in DBH were not founded between treatments any time. However, WP was higher on T1 than T2, T3 and T4 measured to 120 months, while T3 had the lowest WP comparing with T1 and T5. The utilization of herbicide control increased DBH in initial stages, while mechanical control in the inter-row area increased WP in harvest time. WP was not affected by row preparation (furrower vs rotavator) at any time, while lower production were obtained with T3 associated to a fewer number of trees after thinning. A reduction on tillage intensity did not produce a reduction on DBH, however WP decreased due to a reduction on tree population at harvest time. The causes of a different plant population dynamics by tillage system after thinning remains unclear.
Wheel traffic effect on air-filled porosity and air permeability in a soil catena across the wheel rut
Authors: Berisso F. E. , Schjønning P. , Lamandé M. , Weisskopf P. , Stettler M. , Keller T.
Published: May 2021

The impact of wheel traffic on soil physical properties is usually quantified by randomly collecting soil cores at specific depths below the wheeled surface. However, modeling studies as well as few measurements indicated a non-uniform stress distribution in a catena across the wheel rut, which might induce different effects on soil physical properties. The objective of this study was to investigate the impact of vehicle traffic on soil physical properties and air permeability by systematic collection of samples in a transect running from the center to the outside of the wheel rut. A field experiment was conducted on a clay loam soil at Suberg, Switzerland, in 2010. Four repeated wheeling were performed by driving a forage harvester (wheel load of 6100 kg and a tyre width of 0.8 m) forward and rearward in the same track. We sampled 100 cm3 intact cores at 10, 30 and 50 cm depth in a soil catena running from center of the wheel rut to unwheeled part of the field ( 0, 20, 40, 50,60 and 400 cm horizontal distance). We measured water retention and air permeability (ka) at -30, -100 and -300 hPa matric potentials. At -100 hPa, we obtained consistently lower air filled under the wheel rut than at the periphery of the wheel rut (0.4 m) or outside the wheel rut. At least one of these differences εa was significant at all soil depths . At all matric potentials, the ka was lowest at the periphery of the wheel rut and highest outside the wheel rut, with intermediate values inside the wheel rut. However significant differences in ka were obtained only at 10 cm depth. The lowest air permeability at the periphery of the wheel rut is interpreted as a distortion of the soil pores due to shear strain rather than isotropic compaction. Our results indicate that sampling in the soil catena can provide better resolution on information about traffic induce changes on soil physical properties.
Long-term effects of different tillage and field operation regimes on soil structure
Authors: Weisskopf P. , Anken T. , Rek J. , Reiser R. , Holpp M. , Keller T.
Published: May 2021

Only little is known about the rate and extent of structural evolution under the combined influence of tillage and wheeling. Whereas some quantitative information on the regeneration of compacted soils is available, the course and potential of structure formation and recovery under the absence of wheel traffic – as made possible by Controlled Traffic Farming (CTF) systems using permanent traffic lanes – are not well investigated and understood. Therefore the effects of tillage practices and field traffic organization on soil structure were studied in a crop sequence under practical soil management conditions on a loamy orthic luvisol at Tänikon, Switzerland (1187 mm mean annual precipitation, 8.0 °C mean annual temperature). From 2000 to 2008 the effect of no-till on soil structure evolution was studied on a formerly ploughed field and compared to continuously ploughed plots. Since 2008 the previous random field traffic organization was maintained in the ploughed and no-till plots, but changed to controlled traffic in plots formerly under shallow tillage and consecutively managed by no-till. Soil structure evolution was described by repeated samplings of undisturbed soil cores in the top- (10-15 cm) and subsoil (35-40 cm) and subsequent analysis of porosity, permeability and strength characteristics in the lab. In situ measurements of parameters characterizing soil water regime (volumetric water content, matric potential) and the soil environment (O2- and CO2-concentrations in soil air, oxygen diffusion rate, redox potential) under field conditions were done quasi continuously at several soil depths. Results show a slow evolution of structural properties in the subsoil and a limited structure formation in the absence of tillage measures in the topsoil. Soil structure evolution can be followed up in short-term cycles covering individual vegetation periods as well as in medium-term cycles covering crop rotation periods. In situ measurements of water retention characteristics and properties of soil environment revealed consistent but minor effects of field traffic organisation on processes depending on soil structure as well as on weather conditions.
Advances in the research on peach yellows disease, in the productive areas of Jujuy, Argentina
Authors: Curzel Viviana , Fernández Franco , Conci Luis , Bejarano Noemí
Published: May 2021

In Jujuy, there are 850 hectares of peach trees (Prunus persica L.), 800 hectares are found in the temperate valleys, where plants with symptoms of yellowing, redness, leaf curl and necrosis, premature defoliation and shortening of internodes, even plant death, began to be observed a few years ago. The causal agent is Argentinean Peach Yellows phytoplasma (arpy), from the subgroup: 16Sr III-B, X-disease. The disease is called “peach yellows”, and it is an expanding pathology without records in the country. Hence, the objective of this study was to know its epidemiology: presence and dispersion in introduced and naturalized cultivars, characterization of the symptoms and their seasonal variation. Through visual surveys, the prevalence/incidence of the pathology in arid and temperate valleys was estimated during the past crop cycle. In arid and high temperate valleys, symptomatic plants were no recorded; however, diseased plants were visualized in the low temperate valleys and the diagnosis was confirmed in the laboratory. Seasonal variation of the symptoms was observed, in spring, the plants were partially or totally affected, with shortening of internodes, witches' broom on leaves, yellowing, reddening and stiffening of basal leaves; in summer, symptomatic branches of the previous spring were dead or about to die but without new symptoms; in autumn, there was death of symptomatic twigs and early defoliation. Out of 25 productive lots surveyed, in Flordaking, Opedepe and Rojo Dos cultivars, a prevalence of 100 % was determined. The incidence in plants was highest in Flordaking. The severity of the disease, using a 6-degree scale, reflected that of a total of 8,871 surveyed plants, the highest degrees of severity were observed in Flordaking plants, followed by Opedepe and, finally, Rojo Dos.
Tools to modify cherries harvest time in Alto Valle de Río Negro and Neuquén, Argentina
Authors: Raffo Dolores , Curetti Mariela
Published: May 2021

Cherry production is characterized by a very short fruit development period that covers an average of 80 days from flowering to harvest. Although there are varieties with different cycles, the harvest in Alto Valle de Río Negro and Neuquén, Argentina, is highly concentrated. The possibility of extending the harvest period allows to improve logistics, decongest packing work and regulate to a certain extent the supply of cherries on the market. Fruit cherries are highly perishable non-climacteric fruits and have low supply in counter season, which determines an unsaturated foreign market and the possibility to obtain good prices. The highest prices on the market depend on the fruit size and fruit quality and the harvest time (early and late). The aim of this work was to evaluate the feasibility of using different growth regulators and bio-stimulants to extend the sweet cherries harvest period. The use of hydrogen cyanamide (HC) in early varieties to advance the harvest and the use of Retard Cherry® (RCH) in late varieties to delay flowering and harvesting were evaluated. In addition, the effect of gibberellins (Gb) on the delay of maturity and improvement in quality in different varieties was evaluated. The use of HC allowed to advance bloom by 10 days and the harvest by 7 days in fruits of New Star, while RCH delayed the bloom (10 days) and maturity (5 days) of Santina, Lapins and Regina cherries. The application of Gb at 20 ppm from straw yellow stage until the start of the pink improves the quality of the fruits, but the effect on delaying maturity decreases with later applications. The use of regulators in cherries allows to extend the harvest window in nearly 10 days, depending on each cultivar and the meteorological conditions of the season.
Effect of phosphites on the content of total phenols and chlorogenic acid in peach-Monilinia fructicola pathosystem
Authors: Leone Andrea , Permingeat Hugo , Mitidieri Mariel
Published: May 2021

Monilinia fructicola is a fungal pathogen responsible for fruit brown rot in many species of the Prunus genus. The use of abiotic elicitors as phosphites is being studied for the induction of fruit resistance as an alternative to the use of synthetic fungicides. The aim of this work was to evaluate the effect of phosphites on the content of total phenols, chlorogenic acid and changes in susceptibility to M. fructicola in peach fruits. Peach fruits of the cultivars Flordaking and Elegant Lady were treated with potassium- and calcium-phosphites, and harvested at three development stages: green fruit (GF), pit hardening (PH) and harvest time (HT). After harvesting, half of them were inoculated with a conidia suspension of M. fructicola under laboratory conditions. Total phenols and chlorogenic acid content were assayed on the skin of the fruits. Results showed different behaviors according to the cultivar. In Flordaking, the phosphite treatment allowed an increase in the content of total phenols in the stages of GF and PH, but not for chlorogenic acid. In the presence of inoculum, chlorogenic acid decreased, but not the total phenols. The Elegant Lady did not show differences in the content of total phenols and chlorogenic acid after the phosphite treatments. Both metabolites exhibited a seasonal behavior.
Overall situation of peach breeding
Authors: Raseira Maria do Carmo , Franzon Rodrigo Cezar
Published: May 2021

Genetic breeding work requires continuity as well as a significant amount of time, work and resources (human, genetic and financial). Despite this, the development of new cultivars has become a fairly good business in the United States and in several European countries. Thus, most large American and European nurseries have their own breeding program. On the other hand, public institutions in several countries are experiencing a strong tendency to obtain and maintain germplasm, genetic studies and breeding techniques. Certainly, joint efforts, such as those mainly by the RosBreed group in the United States and Fruit Breedomics in Europe, are of great importance, as they provide important tools for classical breeders, mainly regarding to molecular markers. The most used method in cultivar development is still the controlled hybridization, followed by phenotypic selection and clonal propagation. Among the priority objectives of most peach breeding programs are: adaptation to climate change (low chilling genotypes; tolerant to high or very low temperatures); productivity; fruit appearance (without pronounced tip or bulge; attractive color, and large size), and fruit quality (sweeter flavor, and flesh firmness); stone adherence (free or semi-freestone for fresh consumption); fruit firmness and conservation (resistance to handling and transportation, low ethylene production) and disease resistance.
Process and In-Service Residual Stresses in Thermal Barrier Systems
Authors: Wigren J. , Pejryd L. , Gudmundsson B. , McGrann R.T.R. , Greving D.J. , Rybicki E.F. , Shadley J.R.
Published: May 2021

Thermal barrier coatings are used in several industries to improve thermal efficiency, for example, of gas turbine engines. The performance and life of thermal barrier coated components depend on many factors. One important factor is the residual stresses in the coating and substrate. Residual stresses can be influenced by the parameters of the application process. Parameters affecting residual stresses include the condition of the substrate, the type of spray application process, and the prespray heat treatment of the substrate. Residual stresses can also change significantly during the life of a thermal barrier coated material. The goal of this work is to quantitatively evaluate the changes in residual stresses of the thermal barrier coating and the substrate during the stages of processing and during simulated in-service testing. Through-thickness residual stresses distributions of the coating and the substrate material were determined using a destructive laboratory method, called the "Modified Layer Removal Method." Thin thermal barrier coatings (less than 0.5 mm) were evaluated in this work. Residual stresses in thermal barrier coated specimens were evaluated at three stages of the processing history: (1) after grit blasting of the Hastelloy substrate, (2) after application of the bond coat, and (3) after spraying the top coat. The effect on residual stresses of substrate temperature during spraying is examined. Changes in the residual stresses for thin thermal barrier coatings are shown at selected stages during the processing history of the coated materials. Differences between residual stresses at the selected stages are identified and discussed. Changes to residual stress distribution due to in-service conditions are examined. The effect of bond coat oxidation is examined by long-term, high-temperature exposure. Also, residual stresses are evaluated for thick thermal barrier coatings after thermal shock testing.
New Fusible Alloys with Enhanced Corrosion Resistance
Authors: Kretschmer I. , Heimgartner P. , Polak R. , Kammer P.A.
Published: May 2021

Fusible Ni-B-Si alloys with a variety of alloy additions (Cr, Mo, Cu etc.) have been in service for many years as fused coatings with moderate corrosion resistance. Both gas- and water-atomised powders have been used with the spray and fuse and with the plasma transferred arc process to produce coatings. As the severity of corrosive industrial environments has increased, for example in waste burning boilers, existing alloys have not provided the desired service performance. This study was undertaken to develop a new family of alloys with improved corrosion resistance without sacrificing usability, wear resistance or cost effectiveness. A range of compositions was prepared and evaluated for deposition characteristic, microstructure, hardness, wear resistance and corrosion resistance in various media. The resulting alloy has an exceptional combination of wear and corrosion resistance in comparison to conventional alloys, when tested under comparable conditions.
Microstructure and Abrasion Resistance of WC-Co Coatings Produced by High Velocity Oxy-Fuel Spraying
Authors: Khan M.S.A. , Clyne T.W. , Sturgeon A.J.
Published: May 2021

Coatings have been produced by HVOF spraying of four different WC-Co powders, using two fuel gases and two oxygen contents in the flame, and characterised in terms of microstructure and resistance to abrasive wear. It is concluded that there is a close correlation between high levels of chemical reaction, occurring during spraying (and possibly during powder production), and poor wear resistance. Good wear resistance is favoured by using low porosity powders, which interact with the atmosphere less readily during spraying, and also by using a flame with a relatively low oxygen content. This probably minimises the degree of reaction by ensuring that conditions are reducing. Use of propylene rather than hydrogen gives coatings with slightly better wear resistance, despite the fact that the flame temperatures are higher. It is concluded that, for this relatively small rise in temperature, the positive effect on inter-splat cohesion seems to outweigh the negative effect of increased decarburisation.
Changes in the Microstructure of Plasma-Sprayed Yttria-Stabilized Zirconia Deposits during Simulated Operating Conditions
Authors: Ilavsky J. , Long G.G. , Allen A.J. , Berndt C.C. , Herman H.
Published: May 2021

The microstructures of as-sprayed and thermally-cycled freestanding and on-substrate deposits of yttria-stabilized zirconia were studied using small-angle neutron scattering (SANS). The SANS analysis allows the interlamellar pores and the intralamellar cracks, which are the two dominant void systems in the microstructure, to be characterized separately. Whereas up to 20% of the void surface area in the as-sprayed deposits was found to be in the cracks, the thermally-cycled deposits contained only a negligible quantity of cracks. At the same time, changes in the pore surface areas between the lamellae (i.e., the interlamellar pores) were much smaller. As a result, the microstructure of the thermally-cycled deposits was much more anisotropic than the microstructure of the as-sprayed deposits. Varying the cooling and the heating rates did not significantly change the microstructure but varying the total time that the deposits were at high temperature did affect the evolution of the surface area. The presence or absence of a bond coat and substrate also did not measurably influence the results.
Fatigue Behavior and Deformation of Aluminum and Steel HVOF Sprayed with WC-Co Coatings
Authors: Ibrahim A. , Berndt C.C.
Published: May 2021

The effect of WC-Co coating on the high cycle fatigue (HCF) behavior of SAE 12L14 steel and 2024-T4 aluminum was investigated. The fatigue tests were performed at room temperature and 370°C. The fatigue life distributions of specimens in the polished, grit blasted, peened, and coated conditions are presented as a function of the probability of failure. HVOF sprayed WC-Co coating has influenced the fatigue life of aluminum and steel. Factors contributing to this influence, which include grit blasting, elastic modulus, and residual stress, are discussed. A three-dimensional finite-element model (FEM) of the coated specimen was used to calculate the stress distribution across the coating and the substrate. The results of the analytical model are in good agreement with fatigue lives observed experimentally.
Damage in Thermal-Sprayed WC-Co Coatings by Repeated Load
Authors: Tajiri T. , Sakoda N. , Yamamoto S. , Watanabe S.
Published: May 2021

Two types of WC-12wt%Co powders, each manufactured by a different process, were thermally sprayed on a medium carbon steel by HVOF, and repeated load tests (rolling contact fatigue test and high cycles fatigue test) were carried out. The surface damages for the two types of coatings were investigated. It has been clear that the coating damages depend on the types of powders. It has been found that in rolling contact fatigue, there are the coatings, in which damage is characterized by delamination, and by a mixture of delamination and cracks. And it has also been found that in high cycles fatigue, there are the coatings, in which damage is characterized by net-like fatigue cracks, and by linear fatigue cracks.
In-Situ Measurements of Residual Stress within Coatings Plasma-Sprayed Under Industrial Conditions
Authors: Bianchi L. , Blein F. , Baradel N. , Jeandin M.
Published: May 2021

In order to determine residual stresses in industrial plasmasprayed coatings, a rather simple apparatus, which monitors the curvature of a beam substrate during the deposition process, has been developed. The experimental set-up consists of a water-cooled rotating cylinder, holding an initially plane substrate, whose curvature is continuously measured using a contacting displacement sensor disposed into the cylinder. The combination of the plasma gun translation and the cylinder rotation allows to reach industrial spraying velocities. Liquid argon cryogenic system is used to control the substrate temperature from about 50°C to more than 300°C independently from the process velocity. A typical recording is analyzed thoroughly and a theoretical approach to residual stress calculation discussed. This method is applied to partially stabilized zirconia coatings performed onto stainless steel substrates for spraying temperatures between 80°C and 210°C.
Síndrome inflamatorio multisistémico pediátrico
Authors: Fung Fallas Michelle Pamela , Vargas Guzmán Amanda , León Quirós Stephanie Paola
Published: May 2021

El síndrome inflamatorio multisistémico pediátrico es un síndrome clínico descrito en los últimos meses en niños y adolescentes, asociado a una infección activa o reciente por SARS-CoV-2, el virus que causa COVID-19. Se caracteriza por fiebre persistente, valores elevados de marcadores de inflamación y disfunción de uno o múltiples órganos. Puede incluir características sugestivas del síndrome de Kawasaki o síndrome de shock tóxico. El diagnóstico se basa en factores clínicos, de laboratorio, ecocardiográficos y epidemiológicos. Los pacientes con enfermedad leve pueden tratarse de forma conservadora, mientras que los pacientes con una enfermedad más grave, deben recibir inmunoglobulina intravenosa. La mayoría de pacientes responden rápidamente al tratamiento.