Low Ability Research Articles

Electrical conductivity enhancement of rGO-MoS2 composite electrode for inverted PSC by parameter optimization

Carbon-based electrodes are widely used in photovoltaic, metal-ion batteries, supercapacitors, and sensors due to their low ohmic resistance and ability to integrate modifiers. Reduced graphene oxide (rGO) represents a promising alternative to graphite in carbon-based electrodes because of its high electrical conductivity, large surface area, and robust mechanical properties. This study aimed to optimize the fabrication parameters of rGO-MoS2 composite electrodes prepared via a one-pot hydrothermal method, focusing on maximizing their electrical conductivity for potential electronic applications. Taguchi analysis was employed to evaluate the impact of three key factors: rGO-MoS2 mixing ratio, annealing temperature, and annealing time. The novelty of this work lies in the systematic optimization approach using the Taguchi method, which allowed for the identification of the most significant factors and their optimal levels. The optimal combination was found to be a 1:1 ratio, 75 °C annealing temperature, and 15-min annealing time, resulting in an impressive electrical conductivity of 11 800 S m⁻1. This optimized rGO-MoS2 composite electrode exhibited an approximate 11 % reduction in sheet resistance compared to the unoptimized composite. Furthermore, all samples show an improvement in sheet resistance values compared to pure rGO and MoS2, which were 82.5 Ω/sq and 48.9 Ω/sq. Numerical simulations further revealed a 13.23 % improvement in device performance when the optimized rGO-MoS2 composite was implemented as the top electrode in an inverted perovskite solar cell, demonstrating the significant potential of this material for various electronic applications.

Boosting carbon utilization efficiency for sustainable methanol production from biomass: Techno-economic and environmental analysis

Concerns about depleted fossil fuels and the climate crisis have intensified the interest in producing biomass-derived methanol. However, the traditional biomass-to-methanol (BTM) process suffers from low carbon conversion ability and serious CO2 emissions caused by the water–gas-shift (WGS) unit. In this study, three novel BTM processes coupled with solid oxide electrolysis, methane pyrolysis, and methane chemical looping technologies are proposed to eliminate WGS unit, and the systematic heat integration is considered to achieve energy cascade utilization. Meanwhile, process performances are comprehensively evaluated to compare the technical, economic, and environmental attractiveness of three novel BTM processes. It is found that compared with the original BTM process, three novel processes significantly improve carbon efficiency by 22%. Meanwhile, CO2 emissions are reduced by 60%. Moreover, the application of methane chemical looping technology is more economical, and the associated net production cost decreases by more than 30%. Additionally, the BTM process coupled with solid oxide electrolysis is more environmentally friendly, whereas the process with methane pyrolysis technology is more exergy-efficient. Overall, the integrated processes have significant application prospects for carbon conversion and mitigation ability as well as economic attractiveness.

Validation and Evaluation of 5 Scoring Systems for Predicting Metastatic Risk in Pheochromocytoma and Paraganglioma.

Currently, 5 scoring systems have been proposed in the literature for predicting metastatic risk in pheochromocytoma and paraganglioma (PPGL): Pheochromocytoma of the Adrenal Gland Scaled Score (PASS), Grading System for Adrenal Pheochromocytoma and Paraganglioma (GAPP), Composite Pheochromocytoma/paraganglioma Prognostic Score (COPPS), Age, Size, Extra-adrenal location, Secretion type (ASES) score, and Size, Genetic, Age, and PASS (SGAP) model. To validate and evaluate these 5 scoring systems, we conducted a retrospective review of cases diagnosed as PPGL at the Department of Pathology, West China Hospital of Sichuan University, between January 2012 and December 2019. A total of 185 PPGL cases were included, comprising 35 cases with metastasis and 150 cases remained metastasis-free for over 8 years after surgery. The criteria of the 5 scoring systems were used for scoring and risk classification. The predictive performance of the 5 scoring systems was validated, compared, and evaluated using concordance index (C-index) and decision curve analysis (DCA). The C-indices for PASS, GAPP, and SGAP were 0.600, 0.547, and 0.547, respectively, indicating low discriminative ability. In contrast, COPPS and ASES had C-indices of 0.740 and 0.706, respectively, indicating better discriminative performance. DCA also showed that the predictive capability of COPPS was superior to that of ASES, with both outperformed PASS, while PASS had better predictive ability than GAPP and SGAP. Our analysis indicated that pathology-based scoring systems cannot accurately predict metastatic risk of PPGL. Establishing a precise prediction system requires integrating clinical, pathologic, and molecular information, using a scientific methodology for predictive factor selection and weight assessment.

Age and Sex Differences in the Contribution of Mean Arterial Pressure to Pulse Pressure Before Middle Age.

A lower ability to buffer pulse pressure (PP) in the face of increasing mean arterial pressure (MAP) may underlie the disproportionate increase in systolic blood pressure (SBP) in women from young adulthood through middle-aged relative to men. To evaluate the contribution of MAP to the change in PP and pressure wave contour in men and women from young adulthood to middle age. Central pressure waveform was obtained from radial artery applanation tonometry in 312 hypertensive patients between 16 to 49 years (134 women, mean age 35 ± 9 years), 185 of whom were on antihypertensive treatment. Higher MAP levels (≥ 100 mmHg) were significantly associated with higher brachial and central SBP (P < 0.001), PP (P < 0.001), incident wave (P = 0.005), AP (P < 0.001), and PWV (P < 0.001) compared to lower MAP levels. The relationship between MAP and brachial PP (P < 0.001), central PP (P < 0.001), incident wave (P < 0.001), and AP (P < 0.01), but not PWV, strengthens with age. The age-related increase in the contribution of MAP to brachial PP (P < 0.001), central PP (P < 0.001), and incident wave (P < 0.001) was more prominent in women than in men beginning in the fourth decade. In multiple regression analyses, MAP remained a significantly stronger predictor of central PP and incident wave in women than in men, independent of age, heart rate, and antihypertensive treatment. In turn, age remained a significantly stronger predictor of central PP and incident wave in women than in men, independent of MAP, heart rate, and antihypertensive treatment. Women of reproductive age showed a steeper increase in PP with increasing MAP, despite comparable increases in arterial stiffness in both sexes. The difference was driven by a greater contribution of MAP to the forward component of the pressure wave in women.

An Electronic Health Record Model for Predicting Risk of Hepatic Fibrosis in Primary Care Patients

BackgroundOne challenge for primary care providers caring for patients with nonalcoholic fatty liver disease is to identify those at the highest risk for clinically significant liver disease.AimTo derive a risk stratification tool using variables from structured electronic health record (EHR) data for use in populations which are disproportionately affected with obesity and diabetes.MethodsWe used data from 344 participants who underwent Fibroscan examination to measure liver fat and liver stiffness measurement [LSM]. Using two approaches, multivariable logistic regression and random forest classification, we assessed risk factors for any hepatic fibrosis (LSM > 7 kPa) and significant hepatic fibrosis (> 8 kPa). Possible predictors included data from the EHR for age, gender, diabetes, hypertension, FIB-4, body mass index (BMI), LDL, HDL, and triglycerides.ResultsOf 344 patients (56.4% women), 34 had any hepatic fibrosis, and 15 significant hepatic fibrosis. Three variables (BMI, FIB-4, diabetes) were identified from both approaches. When we used variable cut-offs defined by Youden’s index, the final model predicting any hepatic fibrosis had an AUC of 0.75 (95% CI 0.67–0.84), NPV of 91.5% and PPV of 40.0%. The final model with variable categories based on standard clinical thresholds (i.e., BMI ≥ 30 kg/m2; FIB-4 ≥ 1.45) had lower discriminatory ability (AUC 0.65), but higher PPV (50.0%) and similar NPV (91.3%). We observed similar findings for predicting significant hepatic fibrosis.ConclusionsOur results demonstrate that standard thresholds for clinical risk factors/biomarkers may need to be modified for greater discriminatory ability among populations with high prevalence of obesity and diabetes.

External validation of the ARCH score in patients undergoing aortic arch reconstruction under circulatory arrest

BackgroundAortic arch surgery with hypothermic circulatory arrest (HCA) carries a higher risk of morbidity and mortality compared to routine cardiac surgical procedures. The newly developed ARCH (arch reconstruction under circulatory arrest with hypothermia) score has not been externally validated. We sought to externally validate this score in our local population. MethodsAll consecutive open aortic arch surgeries with HCA performed between 2014 and 2023 were included. Univariable and multivariable analyses were performed. Model discrimination was assessed by the C-statistic with 95% confidence intervals as part of the receiver operating characteristic (ROC) curve analysis. Model performance was visualized by a calibration plot and quantified by the Brier score. ResultsA total of 760 patients (38.3% females) were included. The mean age was 61 (±13.6) years, with 56.4% of patients' age >60 years. The procedures were carried out mostly emergently or urgently (59.6%). Total arch replacement was performed in 32.5% of the patients, and aortic root procedures were carried out in 74.6%. In-hospital death occurred in 64 patients (8.4%), and stroke occurred in 5.4%. The C-statistic revealed a low discriminatory ability for predicting in-hospital mortality (area under the ROC curve, 0.62; 95% confidence interval, 0.54-0.69; P = .002); however, model calibration was found to be excellent (Brier score of 0.07). ConclusionsThe ARCH score for in-hospital mortality showed low discriminatory ability in our local population, although with excellent ability for prediction of mortality.

More than 20 procedures are necessary to learn small bowel capsule endoscopy: Learning curve pilot study of 535 trainee cases.

Background and study aims The number of procedures needed to acquire a sufficient level of skills to perform an unassisted evaluation of small bowel capsule endoscopy (SBCE) is unknown. We aimed to establish learning curves, diagnostic accuracy, and the number of procedures needed for reviewing small bowel capsule endoscopies unassisted. Methods An expert panel developed a 1-day course including lessons (examination, anatomy, and pathology) and hands-on training. After completing the course, participants received 50 cases in a randomized sequence. An interactive questionnaire about landmarks, findings, and diagnosis followed each case. After submitting the questionnaire, participants received feedback. Data are presented using CUSUM (cumulative sum control chart) learning curves and sensitivity/specificity analyses compared with expert opinions. Results We included 22 gastroenterologists from 11 different Danish hospitals. A total of 535 cases were reviewed (mean: 28; range: 11-50). CUSUM plots demonstrated learning progression for diagnosis and findings during the course, but none of the participants reached a learning plateau with sufficient competencies. The sensitivity for all findings was 65% (95% confidence interval [CI] 0.51-0.82) for the first 20 procedures and 67% (95% CI 0.58-0.73) from case 21 until completion or dropout. The specificity was 63% (95% CI 0.52-0.74) for the first 20 procedures and 57% (95% CI 0.37-0.77) for the rest. Conclusions Our data indicate that learning SBCE may be more difficult than previously recognized due to low discriminative abilities after 20 cases except for the identification of CD. This indicates that 20 SBCE cases may not be sufficient to achieve competency for reviewing SBCE without supervision.

Functional MRI evaluation of hyperbaric oxygen therapy’s effect on hand motor recovery in a chronic post-stroke patient: a case report and physiological discussion

The objective of the case report was to evaluate a specific HBOT protocol as an effective treatment for stroke rehabilitation, specifically improving hand motor function in chronic post-stroke patients. Stroke is the second leading cause of long-term disability worldwide. About 80% of individuals with acute stroke present upper-limb motor impairment, and 50–60% will have persistent disability or weakness at the chronic phase. Impaired upper-limb motor function is highly associated with low self-care ability, limited mobility and poor quality of life. In recent years, there has been evidence of the neuroplasticity effects of HBOT, and HBOT was found to induce neuroplasticity in chronic stages, even years after brain injury. While the healthcare system is primarily focused on teaching patients to live with their impairments, this case report evaluates the effect of a specific hyperbaric oxygen therapy (HBOT) protocol on true stroke rehabilitation, specifically, improving upper-limb function. This case report studied motor task functional MRI (fMRI) activation and resting-state functional connectivity (rsFC) in a 61-year-old right-handed male patient who suffered hemiparesis and physical weakness in the right upper limb two years after his acute insult, pre- and post-treatment of 60 daily HBOT sessions. Motor functions were assessed at baseline and after the treatment using the Fugl–Meyer assessment (FMA) and the handgrip maximum voluntary contraction (MVC). Following the HBOT protocol, the patient’s FMA score improved from 17 (severe impairment) to 31 (moderate impairment), and there was an increase in fMRI activation in both the supplementary motor cortex (SMA) and the premotor cortex (PMA) bilaterally during trials involving the right hand. The lateralization index (LI) decreased from 1 to 0.63, demonstrating the recruitment of the contralesional hemisphere. The region of interest, ROI-to-ROI, analysis revealed increased post-intervention inter-hemispheric connectivity (P = 0.002) and a between-network connectivity increase (z-score: 0.35 ± 0.21 to 0.41 ± 0.21, P &lt; 0.0001). Seed-to-voxel-based rsFC analysis using the right SMA as seed showed increased connectivity to the left posterior parietal cortex, the left primary somatosensory cortex and the premotor cortex. This case report provides additional insights into HBOT-induced brain plasticity and functional improvement in chronic post-stroke patients, and shows HBOT’s potential as an effective, valuable treatment option for those suffering with lingering symptoms after a stroke. This work was conducted by a research team at the Sagol Center for Hyperbaric Medicine and Research at Shamir Medical Center and Tel Aviv University, and published in Frontiers in Neurology. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Multiomics integration identifies regulatory factors underlying reproductive disorders in geese1

Geese, descendants of migratory birds, have preserved the distinct reproductive and lipid metabolism traits of their wild ancestors. Therefore, compared to other poultry, geese have lower egg production ability and a more sensitive susceptibility to fatty liver. Recent research underscores the impact of lipid metabolism disorders on female reproductive health. In this context, we observed reproductive disorders (RD) and lipid metabolism anomalies in certain geese populations. This study systematically elucidated the differences between RD and normal geese at various levels, including genomics, transcriptomics, bile acid metabolomics, and microbiomics, revealing the crucial role of microorganisms. Our study provides a thorough examination of the ovarian anatomical, histological, and transcriptomic profiles between normal and RD geese. Genomic analyses pinpoint mutations in genes associated with bile acid metabolism, highlighting their potential role in RD pathogenesis. The genomic discoveries are substantiated by precise bile acid assays and ileum transcriptome analyses, which expose a significant disruption in bile acid absorption, activation of FXR, and an increase in serum chenodeoxycholic acid (CDCA) concentrations within RD geese. Notably, 16S rRNA sequencing uncovers significantly greater beta diversity in the ileum microbiota of RD geese as compared to the normal group. Both Wilcoxon rank sum test and LEfSe analyses highlighted a marked increase in Romboutsia abundance in RD geese. Experimental cultivation of microbiota with CDCA supplementation confirms the impact of CDCA on Romboutsia lituseburensis (R. lituseburensis) proliferation. Gavage experiments with R. lituseburensis elucidates its involvement in primary follicle reduction via immune-mediated pathways. Collectively, our multi-faceted analysis unravels the intricate involvement of Romboutsia in goose RD, offering insights from genetic, physiological, and microbial dimensions. Our findings not only deepen our understanding of the etiology of RD in geese but also suggest potential avenues for therapeutic interventions targeting bile acid metabolism and the modulation of specific microbiota components.

Protease SfpB plays an important role in cell membrane stability and immune system evasion in Streptococcus agalactiae

Bacteria possess the ability to develop diverse and ingenious strategies to outwit the host immune system, and proteases are one of the many weapons employed by bacteria. This study sought to identify S. agalactiae additional serine protease and determine its role in virulence. The S. agalactiae THN0901 genome features one S8 family serine peptidase B (SfpB), acting as a secreted and externally exposed entity. A S8 family serine peptidase mutant strain (ΔsfpB) and complement strain (CΔsfpB) were generated through homologous recombination. Compared to the wild-type strain THN0901, the absorption of EtBr dyes was significantly reduced (P < 0.01) in ΔsfpB, implying an altered cell membrane permeability. In addition, the ΔsfpB strain had a significantly lower survival rate in macrophages (P < 0.01) and a 61.85 % lower adhesion ability to the EPC cells (P < 0.01) compared to THN0901. In the in vivo colonization experiment using tilapia as a model, 210 fish were selected and injected with different bacterial strains at a concentration of 3 × 106 CFU/tail. At 6, 12, 24, 48, 72 and 96 h post-injection, three fish were randomly selected from each group and their brain, liver, spleen, and kidney tissues were isolated. Subsequently, it was demonstrated that the ΔsfpB strain exhibited a markedly diminished capacity for colonization in tilapia. Additionally, the cumulative mortality of ΔsfpB in fish after intraperitoneal injection was reduced by 19.92–23.85 %. In conclusion, the findings in this study have demonstrated that the SfpB plays a significant role in S. agalactiae cell membrane stability and immune evasion. The immune evasion is fundamental for the development and transmission of invasive diseases, the serine protease SfpB may be a promising candidate for the development of antimicrobial agents to reduce the transmission of S. agalactiae.

Greater utilization of executive functions networks when listening to stories with visual stimulation is related to lower reading abilities in children

Narrative comprehension relies on basic sensory processing abilities, such as visual and auditory processing, with recent evidence for utilizing executive functions (EF), which are also engaged during reading. EF was previously related to the “supporter” of engaging the auditory and visual modalities in different cognitive tasks, with evidence of lower efficiency in this process among those with reading difficulties in the absence of a visual stimulus (i.e. while listening to stories). The current study aims to fill out the gap related to the level of reliance on these neural circuits while visual aids (pictures) are involved during story listening in relation to reading skills. Functional MRI data were collected from 44 Hebrew-speaking children aged 8–12 years while listening to stories with vs without visual stimuli (i.e., pictures). Functional connectivity of networks supporting reading was defined in each condition and compared between the conditions against behavioral reading measures. Lower reading skills were related to greater functional connectivity values between EF networks (default mode and memory networks), and between the auditory and memory networks for the stories with vs without the visual stimulation. A greater difference in functional connectivity between the conditions was related to lower reading scores. We conclude that lower reading skills in children may be related to a need for greater scaffolding, i.e., visual stimulation such as pictures describing the narratives when listening to stories, which may guide future intervention approaches.

Effect of genetic and sex effect on genomic prediction for horn development in Nellore cattle

This study aimed to evaluate the influence of phenotypic classification of horn development, animal sex effect, and non-autosomal SNP (single nucleotide polymorphism) markers on the genetic parameters and genomic prediction ability for horn development in Nellore cattle using the single-step genomic best linear unbiased prediction method. The polled phenotype was evaluated in two (presence and absence of horns), three (scurs and polled offspring from a horned parent, and the polled and horned animals), and four (absence of horn, polled born to a parent with horn, scurs, and presence of horn) phenotypic categories. A total of 12 statistical models were evaluated. The variance components were estimated using the THRGIBBS1F90 software, and a threshold animal model was used for genomic prediction analyses with the single-step genomic BLUP (ssGBLUP) procedure. Accuracy, bias, and dispersion parameters were evaluated based on the linear regression (LR) method. The highest heritability (0.84) was obtained when the polled character was evaluated as a binary trait. The lowest heritability estimates (0.44 to 0.45) for horn development were obtained when the phenotype was classified into three categories. For the same horn development classification method, the heritability estimates were similar regardless of the genomic evaluated models and fixed effects included in the model. For models considering four and three phenotypic categories for horn development, the inclusion of the sex effect as a fixed effect within the CG did not improve the accuracy, bias, and dispersion of genomic predictions for horn development. Analyzing the trait with binary expression, the highest prediction accuracy was observed when the effect of sex was not included in the CG and without the SNPs in the sex chromosomes. These models displayed the highest dispersion, pointing out the low robustness of genomic prediction. In addition, models that use less than four categories to classify the horn development phenotype, with no discrimination between polled and homozygous polled displayed lower prediction ability. The inclusion of non-autosomal SNPs in the analyses for the models considering four phenotypic categories leads to an improvement in prediction accuracy in 5,26 %, bias, and dispersion reduction, 37 % and 4,55 %, respectively, compared with models that only considered autosomal SNPs. The selection using genomic information for the polled trait is feasible, and it is an alternative to obtaining polled Nellore animals. The binary coding of horn development is an unsuitable oversimplification of polled phenotype, and probably, the genetic background of horn development is more complex than previously proposed. The most adequate prediction model to evaluate the horn development in Nellore cattle was considering four phenotypic categories and including non-autosomal SNP in the analyses for genomic prediction purposes of naturally genetically polled animals. Genetic dehorning can be adopted on a large scale as a low-cost and non-invasive approach to increase the frequency of hornless animals using genomic information and mating strategies.

Effect of Stevia rebaudiana stem waste extract on lipid oxidation of salted-dried Pacific saury during chilled storage

Lipid oxidation is the major form of deterioration in salted-dried fish during storage. We here studied the use of Stevia rebaudiana stem (SRS) waste for impeding lipid oxidation of salted-dried Pacific saury fillets during chilled storage. Compared with Vitamin C (VC), the SRS extract (0.2%) significantly delayed lipid oxidation of the salted-dried fish, as determined through assays of the peroxide value, conjugated diene, thiobarbituric acid reactive substances, and acid value; VC is commonly used in salted-dried products. The color results further confirmed the feasibility of the SRS extract in maintaining the quality of the salted-dried Pacific saury fillets. The antioxidant mechanism studies unveiled that the SRS extract exhibited a higher Fe2+-chelating ability than VC, whereas the extract exhibited lower DPPH and ABTS radical-scavenging abilities than VC. This indicated that the high efficacy of the SRS extract in retarding lipid oxidation may be attributable to its higher Fe2+-chelating ability. The in situ Fe2+-chelating assay conducted using confocal laser scanning microscopy further confirmed this conclusion. Potential functional phenolic compounds in the SRS extract were then profiled using the LC-MS method. The SRS waste extract can thus be applied as a natural antioxidant for delaying lipid oxidation of salted-dried fish.

Exploring the potential relationship between short sleep risks and cognitive function from the perspective of inflammatory biomarkers and cellular pathways: Insights from population-based and mice studies.

The molecular mechanism of short-sleep conditions on cognition remains largely unknown. This research aimed to investigate associations between short sleep, inflammatory biomarkers and cognitive function in the US population (NHANES data 2011-2014) and explore cellular mechanisms in mice. Systemic immune-inflammation index (SII) was calculated using blood-cell based biomarkers. Further, we employed integrated bioinformatics and single-cell transcriptomics (GSE137665) to examine how short sleep exposure influenced the molecular pathways associated with inflammation in the brain. To explore the signaling pathways and biological processes of sleep deprivation, we carried out enrichment analyses utilizing the GO and KEGG databases. Population results showed that, compared with normal sleep group, severe short sleep was associated with lower cognitive ability in all the four tests. Moreover, a higher SII level was correlated with lower scores of cognitive tests. In mice study, elevated activation of the inflammatory pathway was observed in cell subgroups of neurons within the sleep deprivation and recovery sleep cohorts. Additionally, heightened expression of oxidative stress and integrated stress response pathways was noted in GABAergic neurons during sleep deprivation. This study contributed to the understanding of the influence of short sleep on cognitive function and its cellular mechanisms.

Implementation Of Strengthening Numeration Literacy And Adaptation Of Technology

It turns out that education held in elementary schools still experiences many obstacles. The obstacles in question include the lack of professional teachers, low student ability, limited infrastructure, and so on. This is the kind of thing that is still being experienced by SDN KI Hajar Dewantara 01. Therefore, the aim of this service is that the team wants to inform the school about the causes of students' low ability in numeracy literacy. Apart from that, the team wants to provide solutions to teachers to improve students' abilities, especially in terms of strengthening numeracy literacy. Not only that, another goal is that the team wants to increase teachers' knowledge in adapting technology for learning. This service includes solving cases so that the suitable method used to analyze data is descriptive qualitative. The research results show that it is not enough to rely solely on school teachers to increase the strengthening of numeracy literacy. For this reason, contribution, collaboration and consistency from various interested parties are needed. Thus, the success of education at the elementary level needs to be fought for better continuity of further education.

Analisis Kemampuan Representasi Matematis Siswa dalam Menyelesaikan Soal Matematika Ditinjau dari Tipe Kepribadian Florence Littauer

This research purpose to describe students' mathematical representation abilities in solving mathematics problems in terms of Florence Littauer's personality type. This type of research is descriptive qualitative with the research subjects being class VIII students at SMPN 2 Sukodadi, totaling 8 students. This research uses technical triangulation, a Florence Littauer questionnaire to determine students' personality types and tests used to determine students' mathematical representation abilities. The results of this research show that students with a sanguine personality with high ability can complete visual and symbolic representations, students with moderate ability are less able to complete verbal representations, and students with moderate ability are less able to complete all indicators of mathematical representation ability. Choleric personality students with medium ability are less able to complete visual and symbolic representation indicators, low ability students are not able to complete verbal representations, and students with low ability are not able to complete all indicators of mathematical representation ability. Melancholic personality students with high abilities can complete all mathematical representation abilities. Phlegmatic personality students with low abilities have not been able to complete all mathematical representation skills

ANALISIS KEMAMPUAN PEMAHAMAN KONSEP MATEMATIKA PADA MAHASISWA DALAM MENYELESAIKAN SOAL MATERI LIMIT FUNGSI

This study aims to determine the ability to understand mathematical concepts in students in solving Limit Function material problems. The research method used in this research is descriptive qualitative method. Subjects were selected based on the UAS scores for the differential calculus course and also with the consideration of the lecturer in charge of the course. The research subjects were 3 students, each of whom had high, medium and low abilities. Data collection in this study used literature study, tests, interviews and documentation. Data analysis techniques in this study are data reduction, data presentation, and conclusion drawing. Then the data were analyzed descriptively qualitatively based on indicators of concept understanding, namely (1) restate a concept, (2) classify objects according to certain properties, and (3) use, utilize and select certain procedures. Based on the results of the research that has been carried out, it can be concluded that: subjects with high abilities are able to fulfill indicators (2) and (3), subjects with medium abilities are able to fulfill indicators (3), and subjects with low abilities are not able to fulfill the three indicators. The findings in this study showed that the three subjects were equally unable to fulfill the indicators of restating a concept where the three subjects were unable to interpret the graph according to what was intended in the question.

Students’ Abilities and Difficulties in Comprehending English Reading Texts at Second Grade Students’ of SMA Negeri 1 Sakra Timur

Reading is one of the four language skills taught in English learning process. Reading comprehension is the process of making meaning from the texts. Reading comprehension is the ability of the students to read the English reading texts, process the texts, and understand its meaning and integrated with what the reader already knows. The students had still low ability and high difficulties in comprehend the text. This study deals with the abilities and difficulties of the students in comprehending English reading texts. This research study aimed (a) to know the students’ reading abilities in comprehending English text, (b) to find out the students’ difficulties in comprehending English text, (c) to identify factors of causing the students’ difficulties in comprehending English text. The research employed qualitative research method. Data were collected through documentation/worksheet test and interview by 25 students’ and English teacher at senior high school in Sakra Timur. Among other findings, the present study reports that the students’ ability in comprehending English reading texts focus on descriptive text was still low. They had got low ability because they had high difficulties in comprehending English text. The difficulties faced by the students were determining main idea, understanding vocabulary, difficulties in making inference, and to looking for the detail information. The factors were causing the students’ difficulties in comprehending consist of two factors internal and external. The internal factors consist of the student difficulties in understanding long sentence, inadequate instruction presented by teacher, and difficulties in understanding vocabulary). The external factor consists of school and house environment. The other problem is the students’ lack of motivation, lack of interest in English, and lack of participant in English learning process. Their low in reading comprehension was due to their difficulties in comprehension.

ANALISIS KEMAMPUAN REPRESENTASI SISWA DALAM MENYELESAIKAN SOAL MATEMATIS BERBASIS ETNOMATEMATIKA

This research aims to analyze the representational abilities of junior high school students in solving ethnomathematics-based mathematical problems. The newest thing is to see the representation of junior high school students when working on ethnomathematics-based mathematical problems, namely the engklek game. The type of research carried out in this research is qualitative research. Data collection methods use tests and interviews. The subjects in this research were MTs 1 Putri Annuqayah students whose address is Jalan Komplek PP Annuqayah Guluk-guluk Sumenep class IX Amazing, 2 students with high mathematical abilities and 2 students with low mathematical abilities. The results of the research show that students with high mathematical abilities are able to fulfill all indicators of representational abilities, namely verbal, visual and symbolic representational abilities, while students with low mathematical abilities are only able to fulfill one indicator of representational abilities, namely symbolic representational abilities.

Penggunaan Media Interaktif Fraction Splat Untuk Kemampuan Berpikir Numerik Siswa Sekolah Dasar Negeri

Implementing Fraction Splat interactive media has significantly improved the numerical thinking abilities of grade 3 elementary school students in fraction material. This research aims to explore the effectiveness of this media in increasing students' understanding of fractions. The research uses descriptive qualitative data collection through written tests, student response questionnaires, interviews, observation, documentation, and the Miles and Huberman model data analysis techniques. The results showed that students with high abilities (TI) showed good skills in understanding and applying the concept of fractions. Meanwhile, students with moderate abilities (SI) show progress in understanding the concept of fractions but still experience difficulties in several aspects, such as participating in presenting discussion results, asking evaluation questions, and writing summaries or conclusions. Meanwhile, students with low ability (RI) have difficulty identifying and calculating fractions but can apply these concepts in everyday situations. Thus, the results of calculating student response questionnaires from the three subjects, it was found that the three subjects showed that the Fraction Splat interactive media was very effective, especially in helping subjects understand fraction material, and was included in the "Good" category with a percentage of 90% of 88.16% for use. Fraction Splat interactive media.