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85 result(s) for "Li, Wai Chin"
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STEM stereotypes predict students’ STEM career interest via self-efficacy and outcome expectations
BackgroundNurturing students’ interest in science, technology, engineering, and mathematics (STEM) careers is a major goal of STEM education. Although the relationship between students’ stereotypical beliefs regarding STEM careers and their career interest can be reasonably hypothesized, research investigating the extent to which and how students’ STEM career interest is directly or indirectly influenced by their stereotypical beliefs is lacking. This study investigated how upper primary students’ stereotypical beliefs regarding STEM careers predicted their STEM self-efficacy and STEM career-related outcome expectations and how these constructs predicted their STEM career interest. Structural equation modelling was used to analyse quantitative survey data of 824 fourth- to sixth-grade students and test the hypothesized models.ResultsStudents’ stereotypical beliefs regarding STEM careers negatively predicted their self-efficacy in STEM activities and career-related outcome expectations. Additionally, the students’ self-efficacy in STEM activities and career-related outcome expectations in turn predicted their STEM career interest.ConclusionsThese results explain the potential indirect effect of STEM stereotypes on students’ career interest through self-efficacy and outcome expectations. The findings highlight the significant role of STEM stereotypes, self-efficacy in STEM activities, and career-related outcome expectations in students’ career development. The implications of this study for STEM education are also discussed.
Arsenic Elevated Groundwater Irrigation: Farmers’ Perception of Rice and Vegetable Contamination in a Naturally Arsenic Endemic Area
Arsenic (As) in groundwater and its accumulation in agricultural produces has caused serious threats to human health. The majority of current research on As mainly focuses on the technical aspects while bypassing the social perspectives. Farmers are the prime stakeholders as well as executors of agricultural strategies, and their adaptation largely depends on how they perceive the risk for which a mitigation strategy is proposed. This study aims to explore how rice and vegetable farmers perceive As accumulation in their rice and vegetables as well as explore current crop- and body-loading status, the subsequent health consequences of As, and alleviation possibilities with mitigation strategies and to investigate if there is an association between their socioeconomic status and their level of perception. Results reveal that one-fourth of the farmers gave a positive message regarding the As-contamination scenario in rice and vegetables. Although 10 farmers’ socioeconomic characteristics were positively significant, distinctive emphasis should be given to five predictor variables explaining 88% variances: knowledge, direct participation in farming, information sources used, participant education, and organizational participation. Path analysis depicts that direct participation in farming presents the highest positive total effect (0.855) and direct effect (0.503), whereas information sources show the highest positive indirect effect (0.624). The mean As content in all five locations was statistically significant at the 5%, 5%, 0.1%, 1%, and 1% probability levels in scalp hairs, rice, vegetables, soils, and irrigation water, respectively. The first principal component (PC1) explains 92.5% of the variation. Significant variations were primarily explained by As levels in irrigation water, rice grain, and soil. Farmers’ perception is far behind the actual field status of As level and its transfer. Therefore, intensified priorities should be administered on the farmers’ characteristics contributing to variances in perception. The findings can be utilized for policy formulation in all As-endemic nations. More multidisciplinary research can be undertaken on farmers’ attitude towards adopting As-mitigation techniques, with a focus on the socioeconomic position found to influence farmers’ perceptions.
Effect of organic manure on Cd and As accumulation in brown rice and grain yield in Cd-As-contaminated paddy fields
Large areas of paddy fields in mining areas in south China have been contaminated by mixed Cd and As. To test the possibility of using organic manure (OM) as a method of reducing Cd and As accumulation in brown rice and increase the grain yield in such paddy fields, two rice cultivars [Jianyou G2 (JY) and Fengyousimiao (FY)] and three amounts of OM (0, 0.5, 1.5 kg/m 2 ) were examined in three Cd-As-contaminated paddy fields (Fogang, Dabaoshan, Fankou) in Guangdong Province. The results show that the application of OM can effectively increase the grain yield and reduce Cd. However, the As concentration was found to increase in brown rice, especially when high levels of OM were used. The addition of OM increased the soil pH and organic matter content in the soils and enhanced the activities of superoxide dismutase (SOD) and catalase (CAT) in plant tissues. Our results suggest that OM can be used as an amendment to effectively decrease Cd accumulation in brown rice in Cd-contaminated paddy fields. However, it is necessary to consider the negative effects of OM amendments when adding OM to As-contaminated paddy fields.
The potential of Mikania micrantha (Chinese creeper) to hyperaccumulate heavy metals in soil contaminated by electronic waste
The objective of this study is to investigate the contributions of Mikania micrantha (chinese creeper) to remediate heavy metal pollutants present in an e-waste-contaminated soil. Different proportions of e-waste soil (0%, 25%, 50%, 75%, and 100% w/w) planted with Cynodon dactylon together with the test species were prepared for testing relative seed germination (RSG), relative root growth (RRG), and germination index (GI) tests. A significant higher value of GI (77.8%) was found in M. micrantha than that of the other species when planting in 100% e-waste-contaminated soil . A significant correlation (< 0.05) was found between heavy metal concentration and germination assays in M. micrantha. A significant decrease in heavy metal concentration of the polluted soil after the experiment indicated that biomolecule development studies to determine the aggregate benefit of M. micrantha for phytoremediation remain to be studied in future.
Behavioural toxicity studies of Cyclope neritea and Nassarius mutabilis exposed to polycyclic aromatic hydrocarbons
The objective of the work was to study behavioural change of Cyclope neritea (sea snail) and Nassarius mutabilis (land snail) upon exposure to different levels of PAHs. Snail’s behaviour was translated and expressed in Behavioural State Score (BSS) where the score ranged from “0” to “5” points refers to the ascending level of locomotion of a snail. A significant difference was found in snail’s behaviour in 25.0 mg/L than in 0.5 mg/L with p value smaller than 0.01. BSS scores appear most frequent on the treatment and control group were 5 (61.5–64.5%) and 2 (41.0–45.0%), respectively. Intersex behaviour was found in all species (i.e. the same sex was grouped together) regardless of PAH concentrations. This is the first reported to study the behavioural change of snail sampled in Hong Kong area when exposed to PAHs. Further studies should be carried on the impact of snail’s behaviour exposure on each congener in the family of PAHs.
An assessment of heavy metal contamination in the marine soil/sediment of Coles Bay Area, Svalbard, and Greater Bay Area, China: a baseline survey from a rapidly developing bay
The objective of this research is to investigate the pollution levels of tin (Sn), arsenic (As), cadmium (Cd), copper (Cu), lead (Pb), mercury (Hg), and zinc (Zn) of soil/sediment taken in Coles Bay Area (CBA), Svalbard, and Great Bay Area (GBA), China, in an attempt to evaluate the pollution potential related to recent development in the areas. A total of 150 soil/sediment samples were collected in each location. Heavy metal concentrations were detectable levels at all sites and the values of Cd of all soil/sediment samples were higher than Dutch Target and Intervention Values. Heavy metal concentration in soil/sediment was further analyzed by principal component analysis (PCA). It was revealed that three components were found in two studying sites and contributed 60.2% and 75.9% of variations to reflect soil/sediment quality in CBA and GBA, respectively. Based on the results of KMO (0.52) and Bartlett’s test ( p < 0.000), there are 32.1%, 15.6%, and 11.1% and 39.45%, 19.01%, and 17.52% of the variance in the first, second, and third component explained that the metal concentration of Pb, Cd, and Sn was highly correlated with the soil/sediment quality in CBA and GBA, respectively. Among these three heavy metals, Cd concentration was the common dominant factor to affect soil/sediment quality in these two study sites. It is recommended that investigation of the sources of pollution (either point or non-point source) during CBA or GBA development and management together with consideration of abiotic (soil)-biotic (organisms) interactions should be taken into account when choosing suitable remediation strategies in the future.
The Development and Validation of a Survey for Evaluating Primary Students’ Self-efficacy in STEM Activities
STEM integration has become a popular concept not only in the context of education practices but also as a way of learning. The integration of the STEM domains is evident in students’ learning experiences when engaging in STEM activities. However, there is a lack of instruments for evaluating students’ levels of self-efficacy in these activities. Therefore, the aims of this study were to develop a survey for evaluating upper primary students’ self-efficacy in STEM activities and to explore whether a student’s gender, grade, and participation in STEM activities predict his or her self-efficacy in STEM activities. A total of 844 fourth-to sixth-grade primary students participated in this study. After pilot testing, exploratory factor analysis and confirmatory factor analysis were conducted, the survey was found to have a single-factor structure with high reliability (Cronbach’s alpha = .90). Linear regression analysis showed that school and out-of-school participation in STEM activities significantly predicted the students’ self-efficacy in STEM activities, while grade and gender did not. The survey developed in this study provides a reliable and valid way to measure students’ self-efficacy in STEM activities. These findings also highlight the importance of encouraging students’ participation in both formal and informal STEM activities.
Heavy metal(loid)s transformation in dust at a lead smelting site
Emitted dust is the major contributor of heavy metal(loid)s in soils located near lead (Pb) smelters, but the mechanisms for transfer of the heavy metal(loid)s in dust are uncertain. The study systematically investigated the geochemical behaviors and liberation mechanisms of heavy metal(loid)s in this process. The results show that Pb, Zn, Cd, and As in two types of dust samples exceeded the allowable standards, and about 80% of Pb and Zn were present in mobile and bioavailable fractions. More than 70% of arsenic in bottom-blowing furnace dust existed in an acid-soluble fraction, while 60% of cadmium in reducing and fuming dust existed in the acid-soluble fraction. Pb isotope results showed that 97.12% of the Pb in the topsoil came from dust emitted during the smelting process. XRD and MLA results illustrated that PbSO 4 , ZnSO 4 , and CdSO 4 were the major minerals in the dust, while the mineral phases of the topsoil were mainly quartz, calcite, dolomite, and muscovite. Based on a combination of mineralogical investigations and geochemical modelling, our findings suggest that liberation of the Pb, Zn, and Cd was primarily dependent on sulfate minerals under acidic conditions, whereas the liberation of As was related to adsorption by iron hydroxide.
Soil microbial community in lead smelting area and the role of sulfur-oxidizing bacteria
The long-term operation of the lead smelter has brought serious heavy metal pollution to the surrounding soil. The microbial community structure and composition of heavy metal contaminated soil is important for the risk assessment and pollution remediation. In this study, a lead smelter operating for more than 60 years was used to investigate the effects of heavy metal pollution on soil microbial community structure and composition in vertical profile. The results showed that the heavy metal content decreases gradually with increasing vertical depth of the soil. The diversity of soil microbial community with moderate pollution was higher than that with low pollution. Regardless of the pollution level, the diversity of soil microbial community was higher in the surface layer than in the bottom layer. The dominant relative abundance genera include Perlucidibaca, Limnobacter, Delftia, Hydrogenophaga, Thiobacillus, Sulfurifustis and Sphingopyxis , showing a higher abundance of sulfur-oxidizing bacteria (SOB). XRD results showed the presence of PbSO 4 in soil, may be due to the enrichment of SOB for the oxidation of sulfur. This sulfur cycle characteristic may be potential for the stabilization and remediation of lead (Pb) into PbSO 4 .
Teachers' Professional Development with Peer Coaching to Support Students with Intellectual Disabilities in STEM Learning
In recent years, STEM learning has become a new education initiative worldwide. However, little research has considered the needs of students with Intellectual Disabilities (ID) in this initiative. Believing that individuals with disabilities should be evaluated and defined by their capacity, strengths, and broad range of interests and abilities, this research investigated this less-explored perspective in STEM learning, namely supporting teachers providing STEM learning for ID students. Four teachers in two special schools for children with intellectual disabilities worked collaboratively with each other in their schools to plan and implement STEM learning. Peer coaching was recommended to the teachers in order to improve their planning of STEM learning and their teaching practices for teachers' professional development (TPD). The qualitative research methodology was used, and detailed analysis of teachers' pre- and post-TPD interviews and reflections to identify good practices that helped ID students accomplish the tasks and disparities that influenced peer coaching was performed. While challenging, with support from peers and due considerations of the special learning needs of ID students, this research provides useful insights for teachers to support ID students in STEM learning, including the use of technology in the STEM learning design, the consideration of inquiry learning based on students' abilities in implementation, and the focus on teachers' disparity and school involvement with peer coaching.