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Journal articles on the topic 'Stem quality'

Author: Grafiati

Published: 10 September 2021

Last updated: 17 July 2025

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Mladenović, Emina, Sandra Cvejić, Siniša Jocić, et al. "Effect of plant density on stem and flower quality of single-stem ornamental sunflower genotypes." Horticultural Science 47, No. 1 (2020): 45–52. http://dx.doi.org/10.17221/10/2019-hortsci.

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The aim of this research was to determine the optimum planting density for the production of high-quality cut flowers with desirable characteristics. 25 single-stem ornamental sunflower genotypes were planted at different densities and evaluated for flowering time, flower diameter, and stem circumference and length over a two-year production cycle. Three spacing patterns were used: 25 × 25 cm, 30 × 30 cm, and 70 × 30 cm, which led to the planting densities of 160 000, 90 000, and 60 000 plants/ha, respectively. The plant density had the most important effect on the stem circumference, flower diameter, and stem length (total variation 52, 60, and 58%, AMMI analysis) and a small effect on the flowering time (total variation 1%, AMMI analysis). Based on environment-focused scaling, all high-density environments could be suitable for the production of single-stem sunflower genotypes. The results demonstrated the adaptation of several sunflower genotypes G9, G11, G12, G21, and G22 as the most suitable based on the optimum flower diameter, stem circumference, and stem length. These results may lead to progress in growing ornamental sunflowers as a cut flower.

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L., Dr AnnieKavitha. "PROMOTING HIGH-QUALITY STEM EDUCATION." International Journal of Advanced Research 4, no. 10 (2016): 48–50. http://dx.doi.org/10.21474/ijar01/2053.

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Knapic, Sofia, Vanda Oliveira, Marika Makkonen, Isabel Pinto-Seppä, and Helena Pereira. "Circumferential variation of heartwood and stem quality in maritime pine stems." European Journal of Forest Research 133, no. 6 (2014): 1007–14. http://dx.doi.org/10.1007/s10342-014-0818-2.

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Simmons, Dillon, J. Spencer Clark, Lori Goodson, Nooshin Darvishinia, and Marzieh Ebrahimi. "Exploring Teachers’ Perceived Needs for Quality STEM Learning Experiences." Journal of Technology and Teacher Education 31, no. 4 (2023): 459–92. https://doi.org/10.70725/454694qgikvi.

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Despite evidenced challenges compared to non-rural areas, rural communities are in a unique position to help address recent national demands for renewed STEM emphasis in schools (Saw & Agger, 2021). This study utilizes interviews from five rural educators who participated in a three-week STEM learning camp to discuss: 1) how teachers perceive the effectiveness of STEM learning opportunities at increasing student aspirations in STEM fields, and 2) what support and resources teachers need to provide more quality STEM learning opportunities. Learning experiences focused on aerospace engineering, artificial intelligence, and computer science. Camp participants included 310 students, 40 teachers, 33 schools and 27 school districts across one midwestern state. Findings suggest that quality STEM learning opportunities increase many students’ self-efficacy using STEM technologies and aspiration for future STEM careers. Perceptions indicated rural teachers demand more effective PD that emphasizes hands-on experiences, troubleshooting, student-friendly vocabulary, and pedagogy. Teachers advocated for more hands-on and peer-to-peer learning opportunities while avoiding longer lectures and technological issues to better engage students. Lastly, teachers perceived that outside funding, resources, and support are the only realistic way rural teachers can provide more quality STEM learning experiences to students in rural communities. Keywords: Rural education, rural teachers, STEM careers, STEM learning, Research Practice Partnership (RPP), professional development (PD)

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Ghazali, Muhammad Nur Azam, and Muhammed Yusuf. "Achieving Quality Learning Through STEM Education Towards Kindergarten Teachers’ Perceptions." Jurnal Pendidikan Awal Kanak-kanak Kebangsaan 11, no. 1 (2022): 108–19. https://doi.org/10.37134/jpak.vol11.1.10.2022.

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STEM Education is one of the elements that need to be applied in 21st Century Education (PAK- 21). However, STEM Education is given less attention by many early childhood education (ECE) teachers due to various factors that influence its implementation in kindergartens such as lack of exposure to STEM Education information and many more. This study was conducted to see the perceptions of kindergarten teachers on how they think about the importance of STEM Education itself in order to ensure the quality of children's learning can be achieved through STEM Education at the early schooling level. The objectives of this study are (i) to explore the best practices of teaching STEM Education; (ii) to explore the accessibility of informative knowledge through STEM education; (iii) to explore the integration of STEM disciplines in STEM activities; and (iv) to explore the implementation of STEM activities in teaching and learning sessions. There were 4 participants selected in this study and they were kindergarten teachers with different backgrounds. Besides that, a set of interview protocols was used as an instrument in this study containing 16 questions. Data were analyzed using NVIVO software version 10. The findings of the study found that there are various methods, strategies, techniques, and creative teaching methods that can be used in STEM education because it will provide quality learning to children holistically. In line with the agenda of the Ministry of Education Malaysia in elevating STEM Education, it is hoped that the study will be a reference for ECE teachers.

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Wattrus, Samuel J., Mackenzie L. Smith, Cecilia Pessoa Rodrigues, et al. "Quality assurance of hematopoietic stem cells by macrophages determines stem cell clonality." Science 377, no. 6613 (2022): 1413–19. http://dx.doi.org/10.1126/science.abo4837.

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Tissue-specific stem cells persist for a lifetime and can differentiate to maintain homeostasis or transform to initiate cancer. Despite their importance, there are no described quality assurance mechanisms for newly formed stem cells. We observed intimate and specific interactions between macrophages and nascent blood stem cells in zebrafish embryos. Macrophage interactions frequently led to either removal of cytoplasmic material and stem cell division or complete engulfment and stem cell death. Stressed stem cells were marked by surface Calreticulin, which stimulated macrophage interactions. Using cellular barcoding, we found that Calreticulin knock-down or embryonic macrophage depletion reduced the number of stem cell clones that established adult hematopoiesis. Our work supports a model in which embryonic macrophages determine hematopoietic clonality by monitoring stem cell quality.

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Dranski, João Alexandre Lopes, Ubirajara Contro Malavasi, and Marlene de Matos Malavasi. "RELATIONSHIP BETWEEN LIGNIN CONTENT AND QUALITY OF Pinus taeda SEEDLINGS1." Revista Árvore 39, no. 5 (2015): 905–13. http://dx.doi.org/10.1590/0100-67622015000500013.

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ABSTRACT The essay objective was to correlate lignin content resulting from tigmomorphogenesis induced by stem swaying with survival and post-planting growth of P. taeda seedlings. Seedlings were subjected to daily frequencies (0, 5, 10, 20 and 40 movements) of stem swaying for 60 days. By the end of the treatments, we determined lignin content of below and aboveground seedling tissues. Four replicates per treatment were planted in a area cultivated with pines. Ninety days after planting, survival and increments of seedling height, stem diameter and stem volume were quantified. Application of 20 stem swayings increased lignin in both below and aboveground plant tissues. Outplanted seedling survival was reduced with 40 stem swayings while growth increments were increased with both 10 and 20 stem swayings. Lignin content from belowground plant tissues was positively correlated with outplanted seedling survival while lignin from aboveground tissues correlated with height and stem volume increments. P. taeda seedlings with higher lignin content have higher survival chances after planting.

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Donaldson, Joseph L., and Karen L. Franck. "A Mixed-Methods Evaluation to Measure 4-H STEM Program Quality." Journal of Youth Development 15, no. 5 (2020): 203–19. http://dx.doi.org/10.5195/jyd.2020.835.

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The 4-H Science: Building a 4-H Career Pathway Initiative was a 3-year collaboration among National 4-H Council, Lockheed Martin, and state 4-H grantees to help more than 50,000 youth in 13 states develop STEM and workforce skills for STEM professions. A mixed-methods design used observations and interviews to assess program quality. Researchers observed 4-H STEM programming and conducted individual and focus group interviews with youth, parents, community volunteers, corporate volunteers, and professionals. Observations were conducted using a validated observational tool, the Out-of-School Time (OST) Observation Instrument with STEM Plug-In. This instrument measured youth relationship building, youth participation, staff relationship building, staff instructional strategies, activity content and structure, and STEM instruction. Findings from the observations and interviews were combined to assess program quality. Sites scoring highest on the OST Observation Instrument reported using quality STEM curriculum, especially National 4-H Youth Science Day lessons. The 4-H STEM programs demonstrated highly evident and consistent youth relationship building (e.g., being friendly and collaborative) and youth participation (e.g.., contributing ideas and taking leadership). Yet, in many cases, STEM youth skill development (e.g., drawing connections to real-world concepts) and STEM staff instructional practices (e.g., discussing how youth could pursue STEM content through their education and/or career) were inconsistent and rarely evident. Recommendations include substantive professional and volunteer development for both STEM competencies and enhanced youth development. The OST Observation Instrument with STEM Plug-In provided a comprehensive tool to evaluate program quality, and it is recommended for use in evaluating other 4-H STEM programs.

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Anderson, Robert G., and Wenwei Jia. "Effect of Cutting Characteristics on Cut-stem Quality of Single-stem Roses." HortScience 31, no. 4 (1996): 654b—654. http://dx.doi.org/10.21273/hortsci.31.4.654b.

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Commercial quality cut-roses were produced in a single-stem production system from single-node cuttings. Single-node cuttings from cut stems of `Lady Diana' rose were characterized by the location of the node of origin in numerical sequence from the flower and initial stem size, large (thick stems, long length, many nodes), moderate (moderate thickness, moderate length, and node number), and small (generally not commercial quality). Cuttings were treated with a 5-second dip in 500 ppm IBA/250 ppm NAA solution, placed in growing media in 8-cm pots and placed under intermittent mist (5 second every 5 minutes) with growing medium temperature of 35°C. Seven sequential crops of rose cuttings were grown from Feb. through May 1995. The initial node of origin was significantly correlated to the final stem length of the single-stem rose and to the number of days for axillary budbreak on the cutting. The number of days to rooting was not effected by the initial node of origin of the cutting. The correlation with initial stem size had variable results.

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Daniele, Nicola, and Francesco Zinno. "Quality controls of cryopreserved hematopoietic stem cells." Acta Haematologica Polonica 46, no. 5 (2015): 347–52. http://dx.doi.org/10.1016/j.achaem.2015.10.002.

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Chen, Jiayu, Yawei Gao, Hua Huang, et al. "The Combination of Tet1 with Oct4 Generates High-Quality Mouse-Induced Pluripotent Stem Cells." STEM CELLS 33, no. 3 (2015): 686–98. http://dx.doi.org/10.1002/stem.1879.

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Brauchle, Maria. "Creating a STEM School Strategy with STEM Scholl Label, the Scientix Project and the Future Classroom Lab." Cultural and Historical Heritage: Preservation, Presentation, Digitalization 9, no. 1 (2023): 154–67. http://dx.doi.org/10.55630/kinj.2023.090112.

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The development of technologies needs well-trained STEM professionals. The transition to quality STEM education requires collaboration among STEM teachers, education researchers, policymakers, and other educational stakeholders. Creating communities for STEM education and supporting STEM teachers in Europe are the main goals of the Scientix project. Since 2021 Scientix maintains the activities of the STEM School Label project. The STEM School Label platform supports schools in developing successful STEM strategies. The Future Classroom Lab is a fully equipped, reconfigurable, teaching and learning environment located in Brussels. Мany European teachers were inspired to retool their classrooms and change their teaching approaches after their visit in the Future Classroom Lab. The article introduces the two platforms of Scientix, STEM School Label, the main ideas of Future Classroom Lab, and part of the Bulgarian contribution to the development of the STEAM education.

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Harun, Mohd Taufek, and Mohd Ikhwan Hadi Yaacob. "Assessing the Quality of FZ-STEM Module: Validity and Reliability Aspects." Jurnal Pendidikan Sains dan Matemaitk Malaysia 11, Sp (2021): 107–17. http://dx.doi.org/10.37134/jpsmm.vol11.sp.10.2021.

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This study aims to assess the validity and reliability of the FZ-STEM Module that has been developed according to the Sidek’s Module Development Model. The content validity of the FZ-STEM Module was assessed by ten experts in the field related to teaching and learning (T&L) and STEM education. To test the reliability of the FZ-STEM Module, a pilot study was conducted on 40 students in a secondary school. Student attended all the activities suggested in the FZ-STEM Module. Then, student’s feedback were assessed by answering a module’s reliability questionnaire. Overall, the FZ-STEM Module obtained good content validity as well as excellent reliability respectively with an overall mean value is 0.99 and Cronbach’s alpha value is 0.867. The researcher has taken into account all the suggestions and comments from the experts and made improvements so that it can be utilised as an effective STEM teaching module. This module is hope to be an additional module to the existing STEM integration module and serves as a reference for teachers and students to conduct T&L based on the STEM approach. Plus, this study is expected to provide an overview of the implementation of STEM T&L based on Project Based Learning (PjBL) approach that can affect the enhancing of 21st Century Skills and student’ Higher Order Thinking (HOTs) achievement.

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Warnock*, Daniel, Megan Fifarek, and Heather Lash. "Production System Impacts Quality of Cut Poinsettia Stems." HortScience 39, no. 4 (2004): 893B—893. http://dx.doi.org/10.21273/hortsci.39.4.893b.

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The development of the Renaissance series of cut poinsettias, Euphorbia pulcherrima, presents unique opportunities and challenges to cut flower producers. This series has curled bracts, long stem length, excellent vase life and is highly marketable. Literature indicates that this crop is suited for pot or bed production, but does not compare methods. This study assessed the impact of production system on final stem quality. Uniform rooted cuttings of `Renaissance Red' obtained from a commercial supplier were transplanted into 30.5-cm pots or a 1.2-× 2.4-m bed containing a soilless media to obtain 2 plants per 0.9 m2. A total of 56 cuttings were used for each production system and grown using standard production techniques. Transplanting occurred on 11 Aug. 11 2003 with plants reaching market stage, two cyathia shedding pollen, about 17 weeks later. To minimize border effects, plants in the outside rows of each production system were discarded. Thus, stem length, stem diameter, bract diameter, floral development, and number of axillary shoots were determined for 30 interior plants in each system. The production systems differentially impacted stem length and number of axillary shoots. Mean stem length in the bed system (89.7 cm) was greater than that observed in the pot system (71.4 cm). Plants in the bed system had significantly fewer axillary branches per plant (0.5) than plants in the pots (2.0). Stem diameters were similar for both systems (11.5 mm and 10.9 mm for bench and pot, respectively) as were bract diameters (14.3 cm and 13.4 cm for pot and bench, respectively). Both systems produced marketable stems; however, stems produced in the bed system had longer stems, fewer axillary branches, and were more uniform than those in the pot system.

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Stump, Sheryl L., Joel A. Bryan, and Tom J. McConnell. "Making STEM Connections." Mathematics Teacher 109, no. 8 (2016): 576–83. http://dx.doi.org/10.5951/mathteacher.109.8.0576.

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Draganova-Hristova, Ruska, and Snejana Iordanova. "Determinants of STEAM-Based Science Learning in Primary Schools." Strategies for Policy in Science and Education-Strategii na Obrazovatelnata i Nauchnata Politika 33, no. 1 (2025): 129–40. https://doi.org/10.53656/str2025-1-8-det.

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The researched problem is justified through certain normative documents, legal norms, and possibilities. Results of conducted studies related to the use of pedagogical methods by teachers in their direct teaching work, as well as regarding STEM and STEAM-based learning, are presented. Determinants of STEAM-based education, the conditions that influence the quality of the educational process, and the factors affecting it are derived. Attention was paid to the mobile furnishing of the STEM center of “Bacho Kiro” Elementary School as a prerequisite for creating conditions for the fuller application of STEAM-based learning.

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Assou, Said, Julien Bouckenheimer, and John De Vos. "Concise Review: Assessing the Genome Integrity of Human Induced Pluripotent Stem Cells: What Quality Control Metrics?" STEM CELLS 36, no. 6 (2018): 814–21. http://dx.doi.org/10.1002/stem.2797.

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Bowles, Annie C., Dimitrios Kouroupis, Melissa A. Willman, Carlotta Perucca Orfei, Ashutosh Agarwal, and Diego Correa. "Signature quality attributes of CD146+ mesenchymal stem/stromal cells correlate with high therapeutic and secretory potency." STEM CELLS 38, no. 8 (2020): 1034–49. http://dx.doi.org/10.1002/stem.3196.

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Warnock, Daniel F., and Heather Lash. "Pinching Impacts Cut Poinsettia Stem Quality and Profit Potential." HortScience 40, no. 4 (2005): 1123A—1123. http://dx.doi.org/10.21273/hortsci.40.4.1123a.

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The development of the Renaissance series of cut poinsettias, Euphorbia pulcherrima, presents unique opportunities and challenges to cut flower producers. This series has curled bracts, long stem length, excellent vase life, and is highly marketable. Literature indicates that this crop is suited for pot or bed production, but does not compare how cultural methods impact stem quality. This study assessed the impact of pinching on final stem quality and crop profitability. Uniform rooted cuttings of `Renaissance Red' obtained from a commercial supplier were transplanted into a 1.2 × 2.4 m bed containing a soilless media to obtain two plants per 0.09 m2. A total of 56 cuttings were used and grown using standard production techniques. Transplanting occurred on 29 July 2004 with half of the plants being pinched on 19 Aug. 2004. To minimize border effects, plants in the outside rows were discarded. Upon harvest, stem length, stem diameter, bract diameter, floral development, and number of axillary shoots were determined for 30 interior plants. Both pinched and unpinched plants produced marketable stems; however, unpinched plants produced longer thicker stems with larger bracts. The number of stems obtained per square foot was greater with the pinched plants. While overall quality was reduced, this increase in stem number offset potential lost profit. The production of quality cut stems of `Renaissance Red' poinsettias is possible with either pinched or unpinched plants.

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BUXTON, D. R., G. C. MARTEN, and J. S. HORNSTEIN. "GENETIC VARIATION FOR FORAGE QUALITY OF ALFALFA STEMS." Canadian Journal of Plant Science 67, no. 4 (1987): 1057–67. http://dx.doi.org/10.4141/cjps87-142.

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When normally harvested for hay, the basal portion of alfalfa (Medicago sativa L.) stems is low in forage quality. This study was conducted to determine whether genetic variation for in vitro digestible dry matter (IVDDM) and crude protein (CP) concentration of stems of perennial Medicago spp. could be identified and whether morphological and chemical traits were associated with variation in these characteristics of stems. The lower six nodes and internodes of stems and total herbage from 64 Plant Introduction (PI) accessions and five cultivars of field-grown plants were harvested twice when most plants were at the early seed-pod stage of maturity. Several morphological and growth traits were measured, and both stems and total herbage were evaluated for IVDDM and CP concentration. Covariant analysis was used to adjust in IVDDM and CP concentration of stems for differences in plant maturity. Significant variation for IVDDM and CP concentration in stems existed among the cultivars and among the accessions. Some accessions had significantly higher stem IVDDM or CP concentration than control cultivars. The M. sativa accession, PI 440496, had the fourth highest stem IVDDM and third highest stem CP, with concentrations of 374 and 79 g kg−1, respectively. The number of ridges on stems (stem shape) was significantly correlated with stem IVDDM and CP concentration with average correlation coefficients of 0.30 and 0.35, respectively. Cell-wall concentration and lignin concentration per unit cell wall of stems were both negatively correlated with stem IVDDM and CP concentration. Selection for improved nutritive value of stems may have potential for improving the nutritive value of alfalfa herbage.Key words: Alfalfa, forage quality, crude protein, in vitro digestibility, Medicago sativa L.

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Ye, Wei, and Jiyuan Xu. "Research on Innovative Training of Localized STEM Teachers Grounded in Shared Commitment." Journal of Contemporary Educational Research 7, no. 12 (2023): 253–57. http://dx.doi.org/10.26689/jcer.v7i12.5818.

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The high-quality development of a country driven by talent necessitates comprehensive and practical STEM (Science, Technology, Engineering, and Mathematics) education. The goal of localizing STEM education is to cultivate comprehensive innovative technology talents that meet the needs of the new era. STEM teachers play a core role in this concept, and the quality of teacher training directly determines the development trend of STEM education and the quality of future talents in the country. Therefore, based on the current situation and existing problems in STEM teacher training, the shared commitment to “high-quality STEM teacher training” is employed as a guiding principle, highlighting the role of various elements in the STEM teacher training process. The practical path for STEM teacher training is proposed from four aspects: top-level design goal orientation, resource integration to solve supply imbalance, curriculum construction to improve the teaching system, and sustainable development to enhance professional ability. This study hopes to provide guidelines for innovative training of localized STEM teachers in China.

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Li, Yixuan, Li Xie, Jie Wang, et al. "Improving Stem Cell Clinical Trial Design and Conduct: Development of a Quality Assessment Tool for Stem Cell Clinical Trials." Stem Cells International 2020 (November 7, 2020): 1–9. http://dx.doi.org/10.1155/2020/8836372.

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Background. Clinical trials are at the cornerstone of evidence-based stem cell therapies, but the quality assessment for designing and conduct these sometimes-complex studies are scarce of evidence. This study is aimed at developing a handy quality assessment tool for stem cell clinical trials, enhancing capacity of the self-regulate overall quality, and participating protection. Methods. The framework of quality assessment tool was based on the PQRS (progress-quality-regulation-scientific) quality assessment tool, and detailed quality indicators were developed by leader group discussion, expert consulting, and literature review. Stem cell clinical trials were retrieved from the International Clinical Trials Registry Platform, and corresponding quality indicators were assessed and extracted. The validity and feasibility of conceptual quality assessment tool were further evaluated by using structural equation modeling. Results. The quality assessment tool for stem cell clinical trials contains four critical quality attributes, including participant protection, scientific value, quality control, and stem cell products, and 9 observed quality indicators. From 11 primary clinical trial registries in the International Clinical Trials Registry Platform, 9410 stem cell trial registrations were identified, and 1036 studies were eligible for publications and protocols screening. After reviewed full text, 37 studies were included in the validity and feasibility evaluation: 32 studies were completed, and 3 studies terminated early. Most of the studies (83.79%) were in the early phase, and 63.16% of the studies were investigator-initiated trial. To further tested for validity, the critical quality attributes and quality indicators (QIs) between expertise further validated by the SEM method, which showed a good fit for the model ( chi − square = 26.008 ; P = 0.353 ; TLI = 0.967 ; CFI = 0.978 ; RMSEA = 0.048 ). Compared with exploratory trials, evaluating using the quality assessment tool, confirmatory trials performed similarly in participant protection, scientific value, and quality control, but lower in stem cell products. Conclusions. The results of critical quality attributes and quality indicators between expertise and confirmatory validation analysis are basically consistent, indicating the feasibility and validity of applying this quality assessment tool for overall quality evaluation of stem cell trials.

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Anderson, Robert G. "Production Characteristics of High-quality Single-stem Roses." HortScience 31, no. 4 (1996): 597a—597. http://dx.doi.org/10.21273/hortsci.31.4.597a.

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Commercial-quality cut roses were produced in a single-stem production system from single node cuttings. About 1800 rose cuttings in seven sequential crops were identified from 7500 cuttings grown from Feb. through May, 1995. More than 70% of the cut stems harvested from these cuttings were 46 to 75 cm long. Longer stem roses had significantly more nodes and grew from lower, older nodes than shorter rose stems. Longer stem roses required significantly more days to flower harvest because the number of days to axillary bud break was longer than for shorter rose stems. The number of days for rooting, days from axillary bud break to visible bud, and days from visible bud to flower harvest were similar in longer and shorter rose stems. Axillary buds began to grow before rooting in shorter stems and began to grow a mean of 8 days after rooting in the longest rose stems.

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Bamaiyi, Joseph, and Modupe Oniemayin. "Management of stem borers on some quality protein maize varieties." Journal of Agricultural Sciences, Belgrade 56, no. 3 (2011): 197–205. http://dx.doi.org/10.2298/jas1103197b.

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Four Quality Protein Maize (QPM) varieties: Dent, Sakatifu, Flint, Sammaz 14 and TZEE (Local Check) were evaluated for their response to stem borers. Furadan 3G was applied at the rate of 20 kg/ha at planting for the control of the stem borers. The stem borers damage was assessed by determining the number of leaves with ?windows? and plants with ?deadhearts?. The number of exit holes and tunnels on the stem were also determined and the tunnel length measured. Varieties Dent and Sakatifu had more windows, deadhearts, exit holes, tunnels and longer tunnel lengths than varieties Flint and Sammaz 14. The Furadan treatment reduced the borers infestation and increased the yield of the QPM varieties. Varieties Sakatifu and Dent were found to be more susceptible with tunnel lengths of 8.17 and 5.53 cm respectively. Sammaz 14 and Flint were found to be more tolerant to the stem borers infestation and gave the best yields of 3.19 and 2.95 tons/hectare respectively which were not significantly different from TZEE (check).

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Mardis, Marcia A. "Ready for STEM?" Library Resources & Technical Services 58, no. 4 (2014): 250. http://dx.doi.org/10.5860/lrts.58n4.250.

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National emphases on STEM learning and digital textbooks have highlighted the importance of high quality digital instructional materials. Because teachers often lack the time and expertise to find, assess, and organize multimedia, school librarians can support STEM learning by providing media-rich, current, curriculum-linked library collections. To determine whether Discovery Education Streaming, a leading commercial database is a viable source of school library STEM resources, the researcher analyzed its multimedia assets by media, grade, category, and copyright. Results suggested that the database’s extensive content was comprised mainly of video segments, complete videos, and images but that this content was outdated, had uneven grade coverage, and addressed limited topics. While the results raise concerns about Discovery Education Streaming as an enhancement to library collections, careful use of these sources may allow school librarians opportunities to integrate high quality digital assets into their collections through specific strategies for policy, research, and practice.

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Davies, Lindsay J., Ian R. Brooking, Jocelyn L. Catley, and Elizabeth A. Halligan. "Sprouting Temperature and Growth Regulators Influence Cut Flower Quality of Sandersonia aurantiaca." HortScience 33, no. 7 (1998): 1167–71. http://dx.doi.org/10.21273/hortsci.33.7.1167.

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Tubers of Sandersonia aurantiaca Hook. were soaked in 1000 mg·L-1 GA3, 20 mg·L-1 uniconazole, 200 mg·L-1 benzyladenine, or water for 2 hours and then sprouted at 12, 18, or 24 °C. The effects of these treatments on flower stem quality were then determined at forcing temperatures of 18, 24, or 30 °C. Stem length increased with sprouting temperature only at a forcing temperature of 18 °C. Floret numbers increased with sprouting temperature at all forcing temperatures, but the effect was greatest at the 18 °C forcing temperature. The 12 °C sprouting treatment reduced floret numbers at all forcing temperatures. Soaking tubers in GA3 increased stem length but drastically reduced floret numbers, while soaking in uniconazole reduced stem length but had no significant effect on floret numbers. Soaking in BA strongly promoted branching, which resulted in large increases (>30%) in floret numbers per stem with little change in stem length. Of the three growth regulators, only BA was effective in improving cut flower stem quality. Chemical names used: gibberellic acid (GA3); (E)-(+)-(S)-(4-chlorophenyl)-4,4-dimethyl-2-(1,2,4-triazol-1-yl)-pent-1-ene-3 -ol (uniconazole); N6-benzylamino purine (benzyladenine; BA).

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Smith, L., and M. W. Lowdell. "Quality issues in stem cell and immunotherapy laboratories." Transfusion Medicine 13, no. 6 (2003): 417–23. http://dx.doi.org/10.1111/j.1365-3148.2003.00469.x.

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Korbling, Martin, and Christina Branham. "Quality control in stem cell processing for autotransplantation." Transfusion Science 14, no. 1 (1993): 101–4. http://dx.doi.org/10.1016/0955-3886(93)90064-2.

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Sheehy, Sean P., Francesco Pasqualini, Anna Grosberg, Sung Jin Park, Yvonne Aratyn-Schaus, and Kevin Kit Parker. "Quality Metrics for Stem Cell-Derived Cardiac Myocytes." Stem Cell Reports 2, no. 3 (2014): 282–94. http://dx.doi.org/10.1016/j.stemcr.2014.01.015.

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Yaffe, Michael P., Scott A. Noggle, and Susan L. Solomon. "Raising the standards of stem cell line quality." Nature Cell Biology 18, no. 3 (2016): 236–37. http://dx.doi.org/10.1038/ncb3313.

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Russell, Athena L., Rebecca Lefavor, Nisha Durand, Loren Glover, and Abba C. Zubair. "Modifiers of mesenchymal stem cell quantity and quality." Transfusion 58, no. 6 (2018): 1434–40. http://dx.doi.org/10.1111/trf.14597.

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Signer, Robert, Christopher Dillingham, Mary Jean Sunshine, et al. "Hematopoietic Stem Cells Require Elevated Protein Quality Control." Experimental Hematology 64 (August 2018): S104. http://dx.doi.org/10.1016/j.exphem.2018.06.150.

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Encabo, Justin Jacob, Hazel Marie Berja, Chrissa Leaj Chavez, et al. "Sleep Quality of SHS STEM Students Post-pandemic." International Journal of Multidisciplinary: Applied Business and Education Research 4, no. 8 (2023): 2958–65. http://dx.doi.org/10.11594/ijmaber.04.08.32.

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Sleep is an integral component of maintaining overall health and well-being. Inadequate sleep can result in detrimental effects, both on mental and physiological aspects. While the impact of the COVID-19 pandemic on students' sleep quality was extensively examined, there remains a dearth of literature investigating the prevalence of sleep quality after the shift to a post-pandemic lifestyle. This study utilized a descriptive design and gathered data from 202 randomly selected grades 11 and 12 STEM students. We found that 68.81% of them have poor sleep quality. Data also showed that female students obtained high PSQI scores and had a significantly higher prevalence of poor sleep quality than males. However, there was no significant difference in sleep quality between grade levels. In conclusion, sleep quality among STEM students in the post-pandemic setting is poor, implying the need for further assessment of influencing factors in students' sleep patterns, strategies, and management skills. Furthermore, students should be educated on the importance of sleep and the negative consequences of poor sleep quality on regular activities, mental & physical health, and general well-being.

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Baonza Merino, M. V., and A. Gutiérrez Oliva. "Populus clones veneer yield and quality along stem." Forest Systems 11, no. 2 (2002): 312–23. http://dx.doi.org/10.5424/775.

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Some major morphological characteristics in relation to log yield in plywood industries were studied in 13 poplar clones, from Populetum of Zamadueñas (Valladolid). Taper, eccentricity, ovality and bark percentage were analysed. Industrial peeling was made in logs up to 12 m height, analysing the veneer yields and comparing the different quality class among clones at different height levels. Log veneer yields up to 12 m trunk length averaged 60 to 70 % in volume without significant differences among clones. In general, the best performance was found in the middle to lower stem zone. However, clones ‘I-214’, ‘Flevo’, ‘MC’ and ‘PA-1’ maintained their optimum yield even above 10 m height in trunk. ‘Campeador’, ‘I-214’, ‘I-262’, ‘PA-1’ and ‘MC’ showed the best yield and quality performance. ‘Canadá blanco’ and ‘454-40’ have acceptable conditions for this use, but their yield was lower.

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Momin, M. Abdul, Paul A. Wempe, Tony E. Grift, and Alan C. Hansen. "Effects of Four Base Cutter Blade Designs on Sugarcane Stem Cut Quality." Transactions of the ASABE 60, no. 5 (2017): 1551–60. http://dx.doi.org/10.13031/trans.12345.

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Abstract. The cut quality of sugarcane stems during harvesting is of considerable importance, as any damage inflicted on the stems and root systems affects ratooning and reduces yield. In current conventional cutting systems for sugarcane, relatively little attention has been paid to optimizing the cutting dynamics by investigating various blade designs and configurations. One limitation of impact cutting methods is the relatively rapid blunting of the blade edges through wear, leading to stem damage. This study aimed at investigating the effects on sugarcane cut quality of four base cutter blade designs: a conventional straight blade, a 30° angled blade, a serrated blade, and a straight blade with laser cladding on its underside. Blades of each type were installed at a 45° angle on a base cutter fitted to a John Deere 3520 sugarcane harvester. Stem damage, root system damage, and stubble height were considered as cut quality indicators, and blade wear was evaluated as the percentage of metal mass loss after completing each harvesting operation. In this study, the extent of stem and root system damage was classified into nine categories: (1) undamaged stem, not uprooted, (2) undamaged stem, partially uprooted, (3) undamaged stem, uprooted, (4) partially damaged stem, not uprooted, (5) partially damaged stem, partially uprooted, (6) partially damaged stem, uprooted, (7) severely damaged stem, not uprooted, (8) severely damaged stem, partially uprooted, and (9) severely damaged stem, uprooted. The highest percentage of stems damaged during harvesting (approx. 38%) and the highest percentage of root systems damaged (approx. 36%) occurred with the angled blade. The percentages of undamaged stems for the straight, angled, serrated, and laser clad blades were 76.9%, 62.1%, 83.1%, and 72.3%, respectively; partially damaged stems were 11.25%, 21.97%, 11.29%, and 17.73%, respectively; and severely damaged stems were 11.9%, 15.9%, 5.65%, and 9.9%, respectively. Except for the angled blade, all the blades cut almost 80% of stems without affecting the root system, and only 5% of stems were uprooted. Indices for stem damage and uprooting damage were calculated to evaluate the cut quality on a scale from -1.00 (least damage) to +1.00 (greatest damage). For both indices, the serrated blade had values closest to the target value of -1.00, implying the least damage to stems and root systems. Greater stubble heights (110 mm) were observed for the angled blade, with 76% of cut stems above the target 75 mm threshold, which was selected based on the farmer’s suggestion. Comparatively less stubble height was obtained with the serrated and laser clad blades, and roughly 60% of stems were cut in the ideal range (&lt;75 mm). Blade wear percentages per ha of harvested area, based on metal mass loss, were found to be 0.76% for the laser clad blade, 0.83% for the serrated blade, and 0.84% for the straight blade. No mass loss data were collected for the angled blade as it caused such a high level of stem damage that its test was discontinued. The results of this study classified the levels of stem and root system damage occurring in the field during harvesting and their effects on ratooning for four base cutter blade designs. Fundamental guidelines for optimal blade configurations associated with sugarcane harvesting are provided. Keywords: Blade wear, Stem damage, Stubble height, Sugarcane harvester.

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Binotto, Alexandre Francisco, Alessandro Dal' Col Lúcio, and Sidinei José Lopes. "Correlations between growth variables and the Dickson quality index in forest seedlings." CERNE 16, no. 4 (2010): 457–64. http://dx.doi.org/10.1590/s0104-77602010000400005.

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This study aims to identify correlations between growth variables and the Dickson quality index in seedlings of Eucalyptus grandis and Pinus elliottii var. elliottii. The experiment was conducted in a greenhouse and the following variables were observed: stem base diameter, shoot height, number of leaves, leaf dry matter, stem base dry matter, root dry matter, shoot dry matter, total dry matter, ratio of shoot dry matter to root dry matter and ratio of shoot height to stem base diameter in E. grandis 60, 75, 90, 105 and 120 days after seedling emergence, and in P. elliottii 25, 50, 75, 100, 125, 150 and 175 days after seedling emergence. Using Pearson correlation and also path and regression analyses, correlations were analyzed between observed variables according to day after emergence and the Dickson quality index. Stem base diameter was found to have stronger correlation with days after emergence in comparison to shoot height, in both species. Root dry matter was found to have stronger correlation with the Dickson quality index. Stem base diameter was the most suitable parameter to indicate seedling quality due to its higher correlation level with the Dickson quality index. Shoot height was only effective to indicate seedling quality if analyzed together with stem base diameter. Variables relating to dry matter showed the highest correlations with the Dickson quality index (DQI), followed by stem base diameter. Conversely, number of leaves showed the poorest correlations with DQI, followed by seedling height.

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Nuraeni, Fitri, Hafiziani Eka Putri, Nenden Permas Hikmatunisa, Rissa Puspita Sari, Afridha Laily Alindra, and Hun Ravy. "Examining Lesson Quality: An In-Depth Analysis of STEM-based Lesson Design Crafted by Preservice Elementary Teachers." Journal of Innovation in Educational and Cultural Research 5, no. 2 (2024): 337–48. http://dx.doi.org/10.46843/jiecr.v5i2.1369.

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Due to its significance in fostering 21st-century skills, Science, Technology, Engineering, and Mathematics (STEM) education has rapidly evolved across the country. However, designing effective and meaningful STEM-based lessons is still challenging, especially at the elementary school level. Thus, future elementary teachers should be trained to develop integrated STEM-based lesson plans. This research aims to explore the quality of STEM-based lessons designed by pre-service elementary teachers. This study analyzed six STEM-based lesson plans created by 32 preservice elementary teachers as a final group project in the STEM Learning in Elementary School course. Employing a descriptive analysis method, the study evaluated the lesson plans using STEM Integration Curriculum Assessment (STEM-ICA) indicators to shed light on the lesson design quality. Findings reveal varying scores across STEM-ICA indicators, emphasizing ideal science integration but indicating room for improvement in mathematics integration within the lesson. Assessment alignment and the need for stronger connections in engineering design activities are highlighted. This contributes to discussions on enhancing preparation programs for high-quality STEM educators in elementary schools.

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Breems, Dimitri A., Ellen A. W. Blokland, Karen E. Siebel, Angelique E. M. Mayen, Lilian J. A. Engels, and Rob E. Ploemacher. "Stroma-Contact Prevents Loss of Hematopoietic Stem Cell Quality During Ex Vivo Expansion of CD34+ Mobilized Peripheral Blood Stem Cells." Blood 91, no. 1 (1998): 111–17. http://dx.doi.org/10.1182/blood.v91.1.111.

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Abstract Stroma-supported long-term cultures (LTC) allow estimation of stem cell quality by simultaneous enumeration of hematopoietic stem cell (HSC) frequencies in a graft using the cobblestone area forming cell (CAFC) assay, and the ability of the graft to generate progenitors in flask LTC (LTC-CFC). We have recently observed that the number and quality of mobilized peripheral blood stem cells (PBSC) was low in patients having received multiple rounds of chemotherapy. Moreover, grafts with low numbers of HSC and poor HSC quality had a high probability to cause graft failure upon their autologous infusion. Because ex vivo culture of stem cells has been suggested to present an attractive tool to improve hematological recovery or reduce graft size, we have studied the possibility that such propagation may affect stem cell quality. In order to do so, we have assessed the recovery of different stem cell subsets in CD34+ PBSC after a 7-day serum-free liquid culture using CAFC and LTC-CFC assays. A numerical expansion of stem cell subsets was observed in the presence of interleukin-3 (IL-3), stem cell factor, and IL-6, while stroma-contact, stromal soluble factors, or combined addition of FLT3-ligand and thrombopoietin improved this parameter. In contrast, ex vivo culture severely reduced the ability of the graft to produce progenitors in LTC while stromal soluble factors partly abrogated this quality loss. The best conservation of graft quality was observed when the PBSC were cultured in stroma-contact. These data suggest that ex vivo propagation of PBSC may allow numerical expansion of various stem cell subsets, however, at the expense of their quality. In addition, cytokine-driven PBSC cultures require stroma for optimal maintenance of graft quality.

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Stroma-supported long-term cultures (LTC) allow estimation of stem cell quality by simultaneous enumeration of hematopoietic stem cell (HSC) frequencies in a graft using the cobblestone area forming cell (CAFC) assay, and the ability of the graft to generate progenitors in flask LTC (LTC-CFC). We have recently observed that the number and quality of mobilized peripheral blood stem cells (PBSC) was low in patients having received multiple rounds of chemotherapy. Moreover, grafts with low numbers of HSC and poor HSC quality had a high probability to cause graft failure upon their autologous infusion. Because ex vivo culture of stem cells has been suggested to present an attractive tool to improve hematological recovery or reduce graft size, we have studied the possibility that such propagation may affect stem cell quality. In order to do so, we have assessed the recovery of different stem cell subsets in CD34+ PBSC after a 7-day serum-free liquid culture using CAFC and LTC-CFC assays. A numerical expansion of stem cell subsets was observed in the presence of interleukin-3 (IL-3), stem cell factor, and IL-6, while stroma-contact, stromal soluble factors, or combined addition of FLT3-ligand and thrombopoietin improved this parameter. In contrast, ex vivo culture severely reduced the ability of the graft to produce progenitors in LTC while stromal soluble factors partly abrogated this quality loss. The best conservation of graft quality was observed when the PBSC were cultured in stroma-contact. These data suggest that ex vivo propagation of PBSC may allow numerical expansion of various stem cell subsets, however, at the expense of their quality. In addition, cytokine-driven PBSC cultures require stroma for optimal maintenance of graft quality.

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Beniušienė, Lina, Benas Šilinskas, Ričardas Beniušis, Marius Aleinikovas, Edmundas Petrauskas, and Iveta Varnagirytė-Kabašinskienė. "Scots Pine Stem Parameters in Sites with Different Stand Densities in Lithuania." Forests 11, no. 7 (2020): 716. http://dx.doi.org/10.3390/f11070716.

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Background and Objectives: The aim of this study was to determine the effects of different stand densities and thinning regimes on stem quality parameters, mainly branch characteristics, of Scots pine (Pinus sylvestris L.) trees. The study provides some input to the discussion about Scots pine stem quality responses to different forest management practices in relatively young stands. Materials and Methods: Total tree height, height to the lowest live and dead branch, diameter at breast height (DBH), and diameter of all branches from the whorls located up to 6 m from the ground were measured. The linear regression models to predict branch diameter, as the main parameter for the stem quality assessment, were developed based on stand density and stem parameters. Results and Conclusions: DBH, branch diameter and number of branches up to 6-m stem height were significantly higher in the stands with the lowest density. These stem parameters showed a relatively clear downward trend from the lowest to the highest stand densities. The main identified variables which significantly affected stem quality, were branch diameter and diameter of the thickest branch in the bottom part of the stem, at least up to 3-m stem height. For practical use, the best fitted model was estimated when stand density, DBH, and branch diameter up to 3-m height were included in a single equation. The developed model for branch diameter could be used as a forest management tool for managing stem-wood quality.

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Jiang, Bin, Li Yan, Xiaoyan Wang, et al. "Concise Review: Mesenchymal Stem Cells Derived from Human Pluripotent Cells, an Unlimited and Quality-Controllable Source for Therapeutic Applications." STEM CELLS 37, no. 5 (2019): 572–81. http://dx.doi.org/10.1002/stem.2964.

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Zhang, Zhiwei, Luyao Cai, Xiaohan Chen, and Jiaxin Xu. "Dance as a Creative Gateway to STEAM Education Practice——Take the Chinese Classical Dunhuang Dance as an Example." Advances in Education, Humanities and Social Science Research 2, no. 1 (2022): 509. http://dx.doi.org/10.56028/aehssr.2.1.509.

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STEM education emerged in the United States before 1990s, aiming to cultivate scientific and technological talents and improve students' scientific literacy by integrating Science, Technology, Engineering and Mathematics. STEAM is a creative art course with true interdisciplinary integration by adding Art elements to enrich the knowledge covered by STEM courses. This paper integrates Dance into STEAM education, analyzes the new impetus of STEAM dance course in dance education, and designs a STEAM-based dance course with Chinese Classical Dunhuang Dance . Surveys are distributed to determine how parents of teenagers feel about this dance course. The study could enrich contemporary dance curriculums, cultivate scientific and artistic talents, improve the quality of dance education, and promote the development and progress of STEAM education in China.

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Zhang, Zhiwei, Luyao Cai, Xiaohan Chen, and Jiaxin Xu. "Dance as a Creative Gateway to STEAM Education Practice——Take the Chinese Classical Dunhuang Dance as an Example." Advances in Education, Humanities and Social Science Research 1, no. 2 (2022): 509. http://dx.doi.org/10.56028/aehssr.1.2.509.

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Stefanov, Stefan. "The Role and Effectiveness of Improving the Quality of Student's Education of the STEM Method in Profiled Humanitarian High School “St. St. Cyril and Methodius” - Town of Veliko Tarnovo, Bulgaria." Innovative STEM Education 6, no. 1 (2024): 166–72. https://doi.org/10.55630/stem.2024.0619.

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The report describes the forms and methods of education used to improve the quality of education for students at St. st. Cyril and Methodius Profiled Humanitarian High School in Veliko Tarnovo town. Guidelines and good examples are indicated in the STEM idea when working with students from the school with an increased interest in the digital areas of professional and profiled directions in the specialties they have studied in the last few years trough the key role of subjects with directions in IT technologies. Students' creative ideas are described trough realized project approaches on their part. The effect of interest clubs on the increase in learning motivation is discussed, It contains examples of good practices hat led to he participation of students in the National STEM Center - Sofia with their project assignment in competitive forms organized at the national level. Conclusions are structured about the role of effectiveness in increasing the quality of training for trainees in the school.

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Amateis, Ralph L., Philip J. Radtke, and Gerald D. Hansen. "The effect of spacing rectangularity on stem quality in loblolly pine plantations." Canadian Journal of Forest Research 34, no. 2 (2004): 498–501. http://dx.doi.org/10.1139/x03-210.

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The effect of spacing rectangularity on tree stem quality was evaluated using data collected from a loblolly pine (Pinus taeda L.) spacing trial measured at age 19. In this trial, bole condition, branch size, and stem asymmetry were examined on plots with an initial planting density of 2240 trees/ha planted at slight (3:4) and greater (1:3) rectangular spacings to determine suitability for sawtimber production. Results indicated that rectangularity had no significant effect on survival or the number of potential sawtimber trees by age 19. While the 1:3 spacing treatment had a significantly larger maximum branch size than the 3:4 spacing treatment, it could not be attributed to the within-row or between-row direction. Additional measurements on stem diameter at breast height within and between rows failed to show stem asymmetry in the 1:3 spacing treatment. Consequently, rectangular spacings up to 1:3 should not have much impact on overall stem quality.

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Phuong, Nguyen Lan, Le Thi Thu Hien, Nguyen Quang Linh, et al. "Implementation of STEM education: A bibliometrics analysis from case study research in Scopus database." Eurasia Journal of Mathematics, Science and Technology Education 19, no. 6 (2023): em2278. http://dx.doi.org/10.29333/ejmste/13216.

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In response to the long-term challenges of skills shortages and mismatches, many countries worldwide have made significant investments in STEM education. However, to obtain a comprehensive understanding of the progress of global research on the implementation of STEM education, it is essential to compile case studies on STEM education. Therefore, we conducted a bibliometric analysis of 750 publications from Scopus database to assess the bibliographic content of case studies on STEM education from 2006 to 2022. Our main findings show that the first case study on STEM education dates back to 2006, and research in this direction has grown enormously and continuously over the last five years (counting for 72.9%). The most influential articles in the field are cited mainly in the background citations section and help provide an initial perspective for readers to understand the insights discussed later in the study. The most popular journals publishing case studies in STEM education are of good quality, ranking highly in Scopus and Web of Science categories. The analysis results show three main research directions: STEM education in higher education, STEM education expands to STEAM, and STEM education activities in K12-education.

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Zhang, S. Y., Y. C. Lei, and C. Bowling. "Quantifying Stem Quality Characteristics in Relation to Initial Spacing and Modeling Their Relationship with Tree Characteristics in Black Spruce (Picea mariana)." Northern Journal of Applied Forestry 22, no. 2 (2005): 85–93. http://dx.doi.org/10.1093/njaf/22.2.85.

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Abstract This study evaluated and quantified the relationship of tree growth and stem quality characteristics with initial spacing in black spruce (Picea mariana). The study was based on the oldest and mature black spruce initial spacing trial established in 1950 in Thunder Bay, Ontario, Canada. Results show that initial spacing had a direct effect on tree and stem quality characteristics of individual trees. With increasing initial spacing from 1.8 × 1.8 m to 2.7 × 2.7 m, diameter at breast height (dbh), crown size, tree height, tree volume, tree taper, branch size, and clear log length show a steady increase, but the three initial spacings of 2.2 × 2.2 m, 2.0 × 2.0 m, and 1.8 × 1.8 m show no significant differences in these stem characteristics. The results suggest that black spruce may have a low capacity of responding to spacing unless spaced to 2.7 × 2.7 m. Multiple comparison tests support the results with the exception for crown width. This suggests that crown width may be the best density-size indicator for black spruce. As far as tree growth, stem quality, and initial establishment costs are concerned, this study suggests that an initial spacing such as 2.2 × 2.2 m might be optimum for wood production. In addition, this study shows that wide spacings (e.g., 2.7 × 2.7 m) can result in a significant decrease in stem quality and thus may have significant implications for product quality. Furthermore, relationships between major stem quality parameters and tree and stand-level characteristics were examined. Results of the stepwise regression analysis strongly indicate that crown width is important in determining stem quality. The stem quality parameters all have a high adjusted r2 and a low standard error of estimate when regression is made on tree or stand characteristics using the stepwise regression method.North. J. Appl. For. North. J. Appl. For. 22(2):85–93.

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Knapic, Sofia, Isabel Pinto Seppä, Arto Usenius, and Helena Pereira. "Stem modeling and simulation of conversion of cork oak stems for quality wood products." European Journal of Forest Research 130, no. 5 (2011): 745–51. http://dx.doi.org/10.1007/s10342-010-0467-z.

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Tong, Q. J., and S. Y. Zhang. "Impact of initial spacing and precommercial thinning on jack pine tree growth and stem quality." Forestry Chronicle 81, no. 3 (2005): 418–28. http://dx.doi.org/10.5558/tfc81418-3.

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The objective of this paper was to investigate the impact of initial spacing and pre-commercial thinning (PCT) on tree growth, characteristics and stem quality in plantation-grown jack pine (Pinus banksiana Lamb.) after 58 years of growth. Four spacings including three initial spacings without PCT treatment, i.e., 1.52 × 1.52 m (5 × 5 ft), 2.13 × 2.13 m (7 × 7 ft) and 2.74 × 2.74 m (9 × 9 ft) and one initial spacing with PCT treatment (5 × 5 ft thinned to 7 × 7 ft at age 14), were chosen to analyze diameter at breast height (DBH) distribution, survival, and various tree and stem quality characteristics (e.g., DBH, total tree height, stem volume, crown size, branch, taper, sweep and wobbling). Tree mortality during the first 25 growth years was quite low for all four spacings, while after 25 years, survival for the four spacings rapidly declined. The decrease in survival for spacing 5 × 5 was the steepest, followed by spacings 7 × 7, 9 × 9 and finally the PCT-treated stand. DBH distributions for all four spacings were significantly different from each other, and five years after PCT, the 5 × 5 to 7 × 7 spacings had a similar DBH distribution to that of the constant 7 × 7 spacing. Mean DBHs differed significantly among the initial spacings. The 5 × 5 spacing produced significantly smaller trees than did the other three spacings through the years, and the 9 × 9 spacing produced significantly larger trees. PCT had positive effects on DBH growth, and yielded longer merchantable stems and better stem quality. PCT had little effect on crown development. Initial spacing significantly affected diameter growth, crown width and branch development, commercial stem length and volume, stem taper and stem deformation. Narrower spacing produced smaller but better quality stems. Spacing 7 × 7 had the worst stem quality in terms of overall sweep and wave-like transversal deformation (wobbling). A narrow initial spacing followed by a PCT treatment may provide a compromise solution for both tree growth and stem quality. Key words: Initial spacing, thinning, survival, tree growth, stem quality

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Rodrigues, D. B., L. V. M. Tunes, F. A. Villela, et al. "Production Potential and Quality of Chenopodium quinoa Willd. Seed Cultivated in Different Seeding Seasons." Journal of Agricultural Science 11, no. 1 (2018): 251. http://dx.doi.org/10.5539/jas.v11n1p251.

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Quinoa (Chenopodium quinoa Willd.) is an annual plant belonging to subfamily Chenopodiaceae containing such granite importance, being considered a pseudocereal. For the quinoa to gain widespread attention, to the point of achieving large scale cultivation in Brazil it is necessary for the studies to advance specially in regards to quality of produced seeds. The main aim of this work was to evaluate potential of quinoa seed&rsquo;s production cultivated in different seasons, as well as quality of seeds produced on primary and secondary stalks of quinoa plants from BRS Piabiru, produced in the South of Rio Grande do Sul (RS), Brazil. The evaluated seeding seasons were October, November and December, June, July and August of the years 2015/2016, after the plants were taken to evaluation regarding agronomical characters (fresh mass of ramification glomeruli, main glomeruli, fresh mass of stem from the main, fresh mass of stem ramification, fresh mass of leaves, dry mass of stem ramification, stem from the main, glomeruli from the main, stem ramification, of leaves, diameter of stem and panicle lenght) and quality of seeds (germination, test of cold, accelerated aging, and seed&rsquo;s emergency). Quality of the seed is assured when it&rsquo;s produced after months of July, August and November, given that quality of seeds from main stem is superior.

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