Recurrent Issues Research Articles

DDDR-06. ENHANCING GLIOBLASTOMA TREATMENT WITH MOLYBDENUM DISULFIDE(MOS2) NANOMATERIALS AND ULTRASOUND-TRIGGERED TUMOR GROWTH INHIBITION

Abstract INTRODUCTION Glioblastoma, known for its high mortality rate and limited treatment options, poses a persistent challenge in oncology. Despite advances in surgery, radiation, and chemotherapy, patient outcomes have seen only marginal improvements, with ongoing issues of high recurrence and low survival rates. The advent of nanotechnology, particularly the emergence of Molybdenum disulfide (MoS2) nanoparticles, offers new perspective in semiconductors, energy storage as well as cancer therapies. With its unique physical and chemical properties, MoS2 nanoparticles might be promising in its potential roles in the battle against cancer. We aimed to see whether ultrasound-treated MoS2 nanoparticles can interfere with growth of glioblastoma cells. METHODS MoS2 nanoparticles were added to the medium of glioblastoma cells and ultrasound treatments were given. We monitor the cell count as well as cell migration after the treatments. RESULTS MoS2 nanoparticles was found to significantly interfere with tumor cell proliferation and boost the production of reactive oxygen species (ROS). These reactive oxygen species were crucial for the apoptosis of brain tumor cells when in the right concentration. Our analysis also demonstrated that MoS2 impedes cell migration and infiltration, effectively halting tumor expansion. Additionally, Comet assay techniques confirmed extensive DNA damage in the treated cells, highlighting MoS2’s potent DNA-altering capabilities which promote programmed cell death. CONCLUSION The implications of these findings are significant, establishing a solid scientific basis for employing MoS2 nanoparticles as a targeted anti-cancer agent for brain tumors. While this study underscores the transformative potential of MoS2 nanoparticles in clinical oncology, it also acknowledges limitations such as the need for further clinical trials to evaluate efficacy and safety in humans. Key Words: MoS2 nanoparticles, Ultrasound treatment, Reactive oxygen species, Comet assay, Programmed cell death

Serious Games for Education and Training in the Humanitarian Sector: State of the Art

Serious games and game-based learning have seen slow and stymied adoption in the humanitarian sector, despite their general efficacy as training tools. We looked at over 120 games released between 1990 and 2023 that dealt with topics relevant to the humanitarian sector such as disaster risk management, conflict mitigation, human rights and sustainability, and applied the following filters - serious games, games for education and training, and non-commercial games - to obtain a list of 89 serious games that were designed for awareness, education or training in the humanitarian sector. We then noted their accessibility and investigated the following information for each - year of release, developer, format, platforms, context, purpose, target audience, NGOs involved and related research papers - to understand the trends, challenges and future potential of games as a research and pedagogical tool in this field. Of particular interest to us was the subset of 31 training games aimed at professionals, policy makers and stakeholders. We noted concerning trends regarding the accessibility and longevity of games in this field, and tracked recurrent issues facing the development and dissemination of these games, such as the need for a trained facilitator, the difficulty of adapting the content to new settings, a lack of scientific frameworks to guide their design and a lack of long-term impact metrics. However qualitative surveys conducted by the game designers and some third-party researchers indicate that these games remain a valuable addition to traditional forms of education and training and help enliven a difficult topic through experiential learning. We thus propose that involving professional game designers, embracing digital formats, and investing in archiving and long-term impact studies will greatly benefit the development and accessibility of games for humanitarian education and training.

Advancing Diagnostic Accuracy and Quality of Patient Care Through the Implementation of a Flow Cytometry Quality Assurance Program

Abstract Introduction/Objective Flow cytometry immunophenotypic analysis plays an important role in the diagnosis, classification and disease monitoring of hematological neoplasms. However, interpretation of flow cytometry testing can be challenging, especially when using highly complex antibody panels. Thus exploring ways to improve diagnostic accuracy and in turn improving quality of patient care is needed. Methods/Case Report A flow cytometry quality assurance (QA) program was developed. Cases from various complex flow cytometry panels were randomly selected and cross-reviewed by a second pathologist on a daily basis. The outcomes of the QA review were categorized into three groups: complete agreement, minor discrepancy and major discrepancy. Each discrepancy, once identified, underwent a process of documentation, discussion and resolution. The reports were then modified in a timely manner and the clinical teams were notified of the changes. Recurrent issues and common pitfalls were reviewed and discussed at a weekly QA meeting. Here we summarize our 3-years’ experience with this program. Results (if a Case Study enter NA) In total, 6,166 cases were evaluated by the QA program; 6,028 (97.7%) cases showed complete concordance, 120 (2.0%) cases showed minor discrepancies and 18 (0.3%) cases showed major discrepancies. Antibody panels designed to evaluate mature and immature T-cell abnormalities showed the highest rate of discrepancy, 2.8%, whereas panels designed for evaluation of myelodysplastic syndromes showed the lowest discrepancy rate, 1.7%. When analyzing the trends of concordance and discrepancy over time, we found a statistically significant decrease in discrepancies over time, from 4% at the beginning of the QA program to 1.5% in the most recent time interval. Conclusion The overall concordance rate was 97.7%. The remaining 2.3% cases showed discrepancies that required a correction, underscoring the value and necessity of having a QA program. The overall discrepancy rates exhibited a gradual decline over time, indicative of the positive impact of the QA program on enhancing diagnostic competency and accuracy over time.

First report of Sclerotinia minor causing soft rot of Scabiosa atropurpurea in California.

In May of 2019, Scabiosa atropurpurea samples with brown discoloration, soft rot of the crown and lower stem, with presence of white mycelium and black sclerotia (Supp. Fig. 1A, B) were collected from a 0.10 ha open field diversified cut flower production in San Luis Obispo County, CA. Approximately 30 to 40% of the scabiosa crop planted in a quarter of the field, exhibited symptoms. Symptomatic crowns and lower stems from five plants were surface disinfested by rinsing in 0.1% Tween 20, soaking in 70% ethanol for 30 s, 1% sodium hypochlorite for 2 min and sterile water. Disinfested tissue was placed in 1/10 potato dextrose agar (PDA) and incubated at 20°C (12 h photoperiod). Resulting colonies (n = 5) formed abundant white mycelia, with black sclerotia formed on the outer edge of the plates after two weeks (Suppl. Fig. 1C). Sclerotia (n = 50) had an average size of 1.6 (± 0.19) mm in diameter. Morphological identification resulted in Sclerotinia sp. (Hao et al., 2003). The pathogen was further identified by DNA extraction of two hyphal tipped isolates, followed by amplification and sequencing of the rDNA internal transcribed spacer (ITS) region, ITS1/ITS4 (White et al. 1990), calmodulin (CaM), CAL-228F/CAL-737R (Carbone and Kohn, 1999), and DNA replication licensing factor Mcm7 Mcm7-709for/Mcm7-1348rev (Schmitt et al., 2009). NCBI BLAST searches with consensus sequences for each maker revealed 99 to 100% identity with S. minor ex-types for all loci (Supp. Table 1). A maximum parsimony multilocus phylogenetic analysis clustered Californian isolates with reference strains of S. minor (Supp. Fig. 1F). Sequences were deposited in GenBank (Supp. Table 1). Pathogenicity tests were conducted with isolate CS435, which was transferred onto PDA plates and incubated at 20°C for one week. Inoculum consisted of CS435 infested PDA plugs (1 cm3). In the greenhouse, the experiment was set as a complete randomized design and observed for six weeks. Fourteen-week-old scabiosa 'Merlot Red' grown in 3.78 L pots (n = 6), were inoculated by wounding plants at 0.5 cm above the crowns with a 1 mm probe. Inoculum was placed directly on top of the wound and was secured with parafilm. Negative control plants (n = 6) were wounded as above and inoculated with PDA plugs. In experiment 1(19.4 (± 3) °C, RH 46.9), 83% of plants exhibited yellowing of the lower leaves and wilting at one week post inoculation (wpi). Symptoms progressed over time until wilting, major leaf and stem necrosis, was observed in all inoculated plants (Supp. Fig 1E, D). Plant mortality incidence at five wpi was 83%. Pathogen signs including white mycelia and black sclerotia were also observed. In experiment 2 (20.0 (± 10) °C, RH 39.6), 66% of the total plants were symptomatic at five wpi: 33% exhibited yellowing of the lower leaves and wilting, and 33% of plants died. Disease did not develop in non-inoculated plants in either experiment. S. minor was successfully reisolated from surface disinfested tissue of at least 50% (Exp. 1) and 100% (Exp. 2) of inoculated plants, yielding identical sequences to those of the inoculated isolate. S. minor is a soil-borne pathogen that infects tomato, lettuce, brassica, and sunflower crops in California. This study stablishes S. minor as a new soil-borne pathogen of Scabiosa in California. Soil-borne pathogens are a recurrent issue in the cut flower industry, characterizing new pathogens in these crops can inform crop advisors and disease diagnostician to improve disease management in the ornamental industry.

The Progressive Development of International Law on the Return of Stolen Assets: Mapping the Paths Forward

Abstract The return of stolen assets represents a ‘fundamental principle’ of the United Nations Convention against Corruption (UNCAC). The convention’s inclusion of a chapter on asset recovery was considered a groundbreaking achievement at the time of the treaty’s conclusion in 2003. The treaty negotiations concerning these provisions, however, were highly controversial, and the discussions did not benefit from a substantial body of practical experience concerning the return of stolen assets. In the 20 years since the treaty’s conclusion, states have acquired some experience with asset return, and the gaps and limitations in UNCAC’s regime governing asset recovery have become apparent. Article 57 of UNCAC, concerning asset return and disposal, exemplifies the need for progressive development of international asset recovery laws. Article 57 requires ‘updating’ or supplementation because the provision does not adequately address major recurrent issues, such as the recipients, use and monitoring of returned assets; the transparency of the asset return process; and the participation of civil society in the process. Normative development could involve formal law reform, within the UNCAC legal framework, but it could also involve more informal legal change, outside of the UNCAC regime. The Global Forum on Asset Recovery represents an important example of legal change that raises issues of both accountability and effectiveness.

BMP2 Binds Non-Specifically to PEG-Passivated Biomaterials and Induces pSMAD 1/5/9 Signalling.

Biomaterials are widely employed across diverse biomedical applications and represent an attractive strategy to explore how extracellular matrix components influence cellular response. In this study, the previously developed streptavidin platforms is aimed to use to investigate the role of glycosaminoglycans (GAGs) in bone morphogenetic protein 2 (BMP2) signaling. However, it is observed that the interpretation of findings is skewed due to the GAG-unrelated, non-specific binding of BMP2 on components of biomaterials. Non-specific adsorption of proteins is a recurrent and challenging issue for biomaterial studies. Despite the initial incorporation of anti-fouling polyethylene glycol (PEG) chains within biomaterials, the residual non-specific BMP2 adsorption still triggered BMP2 signaling within the same range as conditions of interest. The various options are explored to prevent BMP2 non-specific adsorption and a successful blocking condition involving a combination of bovine serum albumin and trehalose are identified. Furthermore, the effect of this blocking step improved when using gold platforms instead of glass, particularly with Chinese hamster ovary (CHO) cells. With this specific example, it is suggested that non-specific adsorption of BMPs on biomaterials may be a general concern - often undetected by classical surface-sensitive techniques - that needs to be addressed to better interpret cellular responses.

The use of business and technology management (BTM) integrated practice in business development initiatives – an ADR cycle

PurposeThe paper reports a study that evaluated the effectiveness and usefulness of Business and Technology Management (BTM), a management practice for formulating business digital strategies that address organization, processes and technology in an integrative way.Design/methodology/approachThe research followed action design research guidelines that combine the methodological principles of design science research and action research.FindingsEvidence from the study confirmed the adequacy and usefulness of BTM as a solution to an old management problem of internal fit, synergies, alignment or strategic integration. It also led to an improvement in its way of working, namely, a management practice with four process stages: (1) define trade objectives, (2) design an integrated business model, (3) manage the business transformation and execution and (4) evaluate the results obtained.Research limitations/implicationsThe study exemplifies how practice research can be used within a long-term research pursuit to provide empirical evidence that permits evaluating and improving a research-originated management approach.Practical implicationsBeing a theory-for-action, BTM has direct relevance for managers engaged in defining organizational and technological strategies connected with business results. The paper discloses an improved version of BTM together with a description of its application in a medium-sized company operating in the tourism sector.Originality/valueBTM addresses a recurrent issue raised by researchers and practitioners concerning a failure to bring different management perspectives together when formulating a strategy. Therefore, its value lies in its ability to assist in the integration of management perspectives into business development initiatives.

Unravelling the complexities of wetland agriculture, climate change, and coping mechanisms: an integrative review using economics and satellite approaches

AbstractThe flash flood-affected wetland region of Bangladesh contributes around 20–25% of the annual Boro rice production, which is vital for local, regional, and national food security. Considering the crucial significance of Boro rice and the growing susceptibility of wetland regions to flash floods and climate change, it is imperative to investigate viable approaches and adaptation methods to reduce the adverse effects on agricultural output. This review study investigated the relationships between wetlands, climate change, and coping mechanisms while incorporating economic and advanced satellite remote sensing approaches. Through a comprehensive analysis of flash flood impacts on Boro rice yield using satellite remote sensing technique, the findings revealed significant adverse effects on the vegetative reproduction of Boro rice in the study areas. Notably, flash floods in 2017 exhibited more pronounced impacts than other years (2018 and 2019), underscoring the urgency for effective and integrated coping strategies to ensure sustainable agricultural production. Consequently, the study identified and discussed probable coping strategies, including changes in cropping patterns through land suitability assessment, evaluating vulnerable areas through vulnerability mapping, analyzing yield forecasting models, and introducing a damage-based crop insurance approach to mitigate farmers’ losses. These probable adaptation strategies will offer viable solutions to address the recurrent issue of flash floods and safeguard sustainable agricultural production in the wetland areas of Bangladesh. Considering the current situation, climate change issues and probable alternative coping strategies are crucial for developing a resilient agricultural system in light of flash floods, ensuring the long-term viability of wetland agriculture. The study outcomes provide valuable insights for policymakers, researchers, and stakeholders in wetland agricultural planning and management to develop proper and long-term sustainable adaptation and mitigation strategies.

Comparison of Surgical Techniques for Correction of Mandibular Asymmetry in TMJ Ankylosis Patients.

Temporomandibular joint (TMJ) ankylosis frequently results in mandibular asymmetry, which impairs an affected person's ability to function and look good. Because of the intricacy of TMJ ankylosis and the variety of surgical procedures available, correcting mandibular asymmetry surgically can be difficult. Patients with mandibular asymmetry and TMJ ankylosis who had surgery at a tertiary care facility between certain periods were the subject of a retrospective investigation. Medical records were used to gather information on patient demographics, pre-operative imaging, surgical methods, and post-operative results. Surgical methods included condylectomy with or without reconstruction, joint reconstruction with or without orthognathic surgery, and unilateral or bilateral mandibular distraction osteogenesis (MDO). Occlusion, patient-reported results, and facial symmetry made up the evaluation criteria. The study had a total of 50 patients, with different surgical method distributions. Comparing unilateral and bilateral MDO to condylectomy and joint reconstruction, notable gains in face symmetry and occlusion were seen. The largest complication rate was seen with condylectomy, mostly from recurrence and device-related issues, albeit the rates of other procedures varied as well. In conclusion, customized treatment planning is necessary for the correction of mandibular asymmetry in individuals with TMJ ankylosis. Although mandibular distraction osteogenesis produces better results for occlusion and facial symmetry, it is crucial to carefully weigh the risks involved. While still feasible treatments, condylectomy and joint reconstruction require strict monitoring for any consequences. In order to enhance patient care in this difficult patient group, future research should concentrate on improving treatment procedures and long-term results.

Connecting the Dots: Hydration, Micronutrients, and Immunity.

Dehydration, often unnoticed, can occur in adults due to heat-related illnesses, viral infections, and upper respiratory tract infections, leading to deficits in fluids, electrolytes, and energy (FEE), even without diarrhea. This fluid deficit, in turn, impairs immunity at cellular and molecular levels. Physiologically, the immune system rapidly reacts to threats by adjusting its structural permeability, allowing water and small solutes to be passed, facilitated by proteins like aquaporins (AQPs). These AQPs are also essential for immune cell communication and adjustments of the cytoskeleton for functions like chemotaxis and phagocytosis. Apart from hydration, maintaining an optimal intake of essential micronutrients, including vitamins C and E, copper, zinc, and selenium, is also critical for supporting immune function and acting as antioxidants. Transient alterations in immune function caused by acute stressors or nondiarrheal conditions heighten vulnerability to coexisting illnesses, particularly cold and upper respiratory tract infections, while also elevating the likelihood of recurrent health issues. Supplementing fluids with known FEE content according to quality standards and enhanced taste is recommended during acute illness and until complete recovery. Thus, dehydration, caused by various acute conditions, can impair immunity and delay recovery. Prioritizing hydration and nutrition in healthcare and general settings is imperative, even when diarrhea is absent.

Experts’ views on recurrence and progression of varicose veins

Introduction. Despite modern advances in technologies for the treatment and prevention of varicose veins, there is currently no radical treatment for varicose veins. The probability of recurrence of dilated veins, according to various authors, ranges from 5 to 70%. Along with the well-established concept of recurrence of varicose veins, the term progression of varicose veins is increasingly common in everyday life.Aim. To study the current understanding of the term relapse and the practical attitude of specialists involved in the treatment of varicose veins to it.Material and methods. In 2023, a survey of 117 specialists on the recurrence/progression of varicose veins was conducted. The respondents were doctors involved in the treatment of varicose veins: vascular surgeons 22.4%, phlebologists 50%, general surgeons 19.8%, specialists in ultrasound/functional diagnostics 7.8%, X-ray endovascular surgeon 0.85%. The questionnaire included 18 questions regarding the frequency of visits of patients with relapse/progression of varicose veins; views on tactics, as well as the attitude of specialists to the issue of progression and recurrence of varicose veins in patients after its surgical treatment.Results and discussion. The concept of recurrence and progression of varicose veins among specialists dealing with this pathology is not always comparable. There are differences in views both on the predisposing factors for the recurrence of dilated veins, and, accordingly, on the tactics of treatment and preventive measures. In some cases, according to statistics, they are due to specialization.Conclusions. The incidence of relapse and progression at the reception of the respondents has a slight difference. Despite the fact that there are opinions that do not correspond to generally accepted and abhorrent collegiality, mostly specialists try to separate these concepts, see differences in provoking factors and, accordingly, in recommendations.

Predictors for temporary stomas non-closure among non-metastatic rectal cancer patients undergoing curative resection: a retrospective analysis

BackgroundThe primary treatment for non-metastatic rectal cancer is curative resection. However, sphincter-preserving surgery may lead to complications. This study aims to develop a predictive model for stoma non-closure in rectal cancer patients who underwent curative-intent low anterior resection.MethodsConsecutive patients diagnosed with non-metastatic rectal cancer between January 2005 and December 2017, who underwent low anterior resection, were retrospectively included in the Chang Gung Memorial Foundation Institutional Review Board. A comprehensive evaluation and analysis of potential risk factors linked to stoma non-closure were performed.ResultsOut of 956 patients with temporary stomas, 10.3% (n = 103) experienced non-closure primarily due to cancer recurrence and anastomosis-related issues. Through multivariate analysis, several preoperative risk factors significantly associated with stoma non-closure were identified, including advanced age, anastomotic leakage, positive nodal status, high preoperative CEA levels, lower rectal cancer presence, margin involvement, and an eGFR below 30 mL/min/1.73m2. A risk assessment model achieved an AUC of 0.724, with a cutoff of 2.5, 84.5% sensitivity, and 51.4% specificity. Importantly, the non-closure rate could rise to 16.6% when more than two risk factors were present, starkly contrasting the 3.7% non-closure rate observed in cases with a risk score of 2 or below (p < 0.001).ConclusionPrognostic risk factors associated with the non-closure of a temporary stoma include advanced age, symptomatic anastomotic leakage, nodal status, high CEA levels, margin involvement, and an eGFR below 30 mL/min/1.73m2. Hence, it is crucial for surgeons to evaluate these factors and provide patients with a comprehensive prognosis before undergoing surgical intervention.

Clearing the Fog: A Scoping Literature Review on the Ethical Issues Surrounding Artificial Intelligence-Based Medical Devices.

The use of AI in healthcare has sparked much debate among philosophers, ethicists, regulators and policymakers who raised concerns about the implications of such technologies. The presented scoping review captures the progression of the ethical and legal debate and the proposed ethical frameworks available concerning the use of AI-based medical technologies, capturing key themes across a wide range of medical contexts. The ethical dimensions are synthesised in order to produce a coherent ethical framework for AI-based medical technologies, highlighting how transparency, accountability, confidentiality, autonomy, trust and fairness are the top six recurrent ethical issues. The literature also highlighted how it is essential to increase ethical awareness through interdisciplinary research, such that researchers, AI developers and regulators have the necessary education/competence or networks and tools to ensure proper consideration of ethical matters in the conception and design of new AI technologies and their norms. Interdisciplinarity throughout research, regulation and implementation will help ensure AI-based medical devices are ethical, clinically effective and safe. Achieving these goals will facilitate successful translation of AI into healthcare systems, which currently is lagging behind other sectors, to ensure timely achievement of health benefits to patients and the public.

Emergency policies are not enough to resolve Amazonia’s fire crises

The fire crises in the Amazon continues to increase the risk of large-scale forest dieback, threatening regional biodiversity and global climate. This issue gained international attention in 2019 when fires in the Brazilian Amazon led to a fire ban imposition. Despite the uncertainty of its impact, the fire ban was reenacted in subsequent years. Here we assess the effectiveness of each fire ban by comparing observed fire counts with climate-driven predictions of fire for 2019–2021. While the 2019 ban likely reduced the number of fires to expected levels, it was largely ineffective in the years that followed. Four years later in 2023 under a different political dynamic, the Brazilian Amazon faced another fire crisis. Resolving this recurrent issue requires interventions that target the underlying causes of fire and extend beyond emergency measures, including long-term strategies focused on landscape management, public awareness and education, and engagement with local communities and stakeholders.

Coexistence of ankylosing spondylitis and Behçet's disease: Successful treatment with upadacitinib.

Ankylosing spondylitis (AS) and Behçet's disease(BD) are distinct inflammatory disorders, but their coexistence is a rare clinical entity. This case sheds light on managing this complex scenario with Janus kinase (JAK) inhibitors. A 42-year-old woman presented with a decade-long history of lower back pain, nocturnal spinal discomfort, recurrent eye issues, oral and genital ulcers, hearing loss, pus formation in the left eye, and abdominal pain. Multidisciplinary consultations and diagnostic tests confirmed AS (HLA-B27 positivity and sacroiliitis) and BD (HLA-B51). Elevated acute-phase markers were observed. This case fulfills diagnostic criteria for both AS and BD, emphasizing their coexistence. Notably, treatment with upadacitinib exhibited promising efficacy, underscoring its potential as a therapeutic option in patients with contraindications for conventional treatments. Our findings illuminate the intricate management of patients presenting with these two diverse systemic conditions and advocate for further exploration of JAK inhibitors in similar cases.

THE ENGLISH ALPHABET AND ABSTRACTISM: THE METAMORPHOSIS OF TEXTS TO SYMBOLS

The 26 letters of the English alphabet are undoubtedly, within the scope of the most recognizable forms globally even some of the non-English speaking communities. The English alphabet has been subjected to varied elements from speaking to writing. The words used in most local parlances are formulated and written by means of the letters of the English alphabet. However, this English alphabet from the design perspective, as this paper intends to unravel, there is so much to be extracted from the letters of the English alphabet, which has not been addressed. Digital applications were used to harness the abstracted design concepts that emanated from this study. Finally, the recurrent issues of concept generation will be given a significant boost as intrinsic findings from this study show that the methodical exploitation of the letters of the English alphabet can be used to generate infinite thematic genre of abstracted art or flourishes worthy of a variety of elucidations.

Understanding the limits of a screening operation. Part 1: Characterization of screen plugging

Pressure screening is a critical step in the production of high-quality paper. In efforts to meet sustainable market demands, mill operators are forced to push the limits of screening operation to the point where plugging becomes a recurrent issue. This two-part study provides insights into the limits of screening operations. In the first part, some published imaging data was analyzed to delve into the plugging mechanisms. The observed hysteresis and intermittency were measured by image processing techniques, which revealed that an intermittent behavior of plug-and-release events is intensified as permanent, stable plugs start to form. The intermittency was characterized as changes in the distribution of open area fluctuation peaks. Thus, the kurtosis of the fluctuation peak distribution is proposed as a metric for a plugging soft-sensor. In part 2 of this investigation, the limits of screening operation were characterized by performing a series of screening trials. The utility of the soft-sensor metric for plugging was assessed with the pressure fluctuation data.

Multimodal classroom interaction analysis using video-based methods of the pedagogical tactic of (un)grouping

ABSTRACT Grouping of people and/or things in school can involve challenging pedagogical problems and is a recurrent issue in research literature. Grouping of pupils sometimes aids learning, but detailed video-based analysis of how teachers (and pupils) group or ungroup (termed ‘(un)grouping’) in classrooms is rare. This multimodal classroom interaction analysis study builds on previous work by exploring how the Pedagogy Analysis Framework can help untangle complicated classroom interactions involving (un)grouping and identifies sixteen types of (un)grouping. The sample size is one class of thirty pupils (10-year-olds), their class teacher, and teaching assistant. Four research methods were used (lesson video analysis, teacher verbal protocols, pupil group verbal protocols, and individual teacher interviews). Six hours of data were video recorded (managed using NVivo). Data were analysed by two educational researchers, the class teacher, and two groups of pupils (three girls and three boys). The methodology is Straussian Grounded Theory. Data were recorded in 2019. We present how often participants (un)grouped during a lesson. We propose and use a grounded theory for (un)grouping which we call the ‘Exclusion, Segregation, Integration, and Inclusion (ESII) model’. Additionally, we discuss how misinformation and disinformation can complicate analysis of (un)grouping and examine different perspectives on (un)grouping.

A novel reinforcement learning policy optimization based adaptive VSG control technique for improved frequency stabilization in AC microgrids

In this paper, an improved Reinforcement Learning (RL) based approach for adaptive Virtual Synchronous Generator (VSG) control of grid-forming inverters is proposed. High penetration of inverter-based resources causes recurrent frequency stabilization issues. For this matter, a novel model-free Actor–Critic policy optimization technique is proposed to improve frequency transients metrics such as frequency nadir and Rate of Change of Frequency (RoCoF). Stability analysis of the VSG controlled system is conducted through small signal modeling to determine the stability margins of both the virtual inertia parameter J and damping coefficient Dp. The control problem is formulated in RL terms using a new technique for state, action and reward construction that improves the learning process of the agents. The proposed approach’s efficiency is tested for three RL algorithms, namely, Deep Deterministic Policy Gradient (DDPG), Soft Actor–Critic (SAC), and Twin-Delayed DDPG (TD3) with special attention given to the latter. Various performance metrics such as training time and maximum cumulative episodic reward are used to compare the three algorithms. The resulting agent based VSG adaptive controllers are simulated and then compared for power quality and frequency stabilization capabilities. Finally, a comparison between non-adaptive VSG and TD3 based VSG is presented to conclude on the efficiency improvements achieved by the proposed approach.

Methodology for Calculating the Damaged Surface and Its Relationship with Power Loss in Photovoltaic Modules by Electroluminescence Inspection for Corrective Maintenance.

Photovoltaic panels are exposed to various external factors that can cause damage, with the formation of cracks in the photovoltaic cells being one of the most recurrent issues affecting their production capacity. Electroluminescence (EL) tests are employed to detect these cracks. In this study, a methodology developed according to the IEC TS 60904-13 standard is presented, allowing for the calculation of the percentage of type C cracks in a PV panel and subsequently estimating the associated power loss. To validate the methodology, it was applied to a polycrystalline silicon module subjected to incremental damage through multiple impacts on its rear surface. After each impact, electroluminescence images and I-V curves were obtained and used to verify power loss estimates. More accurate estimates were achieved by assessing cracks at the PV cell level rather than by substring or considering the entire module. In this context, cell-level analysis becomes indispensable, as the most damaged cell significantly influences the performance of the photovoltaic model. Subsequently, the developed methodology was applied to evaluate the conditions of four photovoltaic panels that had been in operation, exemplifying its application in maintenance tasks. The results assisted in decision making regarding whether to replace or continue using the panels.