COMPARING PRICE MOVEMENTS OF OPTIONS AND THE UNDERLYING INDEX

Research Project (M.B.A.) - Simon Fraser Universit

What Role Does School Play in Helping Socioeconomically Disadvantaged Students Succeed against the Odds?

Based on the data of a large scale survey conducted by Collaborative Innovation Center of Assessment Toward Basic Education Quality at Beijing Normal University, this study examined the role of school in reducing education inequality. The results showed that schools concentrated with resilient students had higher mean socioeconomic status (SES) and SES heterogeneity, more education resources, higher teaching quality, and more positive school climate, and these factors also functioned as significant predictors of academic resilience. Provid-ing socioeconomically disadvantaged students with access to both high SES schools and enriched school resources can even the education ine-quality related to family background. In order to promote education equality, policymakers and education practitioners should take measures to reduce the degree of stratification and encourage student integration, promote equal distribution of high quality education resources among schools, enhance teachers’ ability to effectively use individualized, coop-erative and inquiry teaching methods, and build a supportive climate

GENDER DIFFERENCES IN MUSCLE CONTRACTION AND CO-CONTRACTION ACTIVITIES DURING THE IMPACT PHASE OF SINGLE-LEG LANDING TASK IN BADMINTON

Our study aimed to explore ACL injury risk factors in females versus males during badminton single-leg landings. Sixteen players (8 male, 8 female) participated, with lower limb kinematics, ground reaction forces, and muscle activity measured using motion capture, force plates, and electromyography (EMG). Independent samples t-test analyzed gender differences in leg kinematics, mean normalized leg muscle activation (MVC%), and muscle co-contraction post-landing. Females, compared to males, exhibited higher rectus femoris, medial hamstring, and gastrocnemius muscle activity during the post-landing phase. Additionally, males had a higher co-contraction ratio in the medial and lateral gastrocnemius than females. Female badminton players\u27 neuromuscular control strategies may lack ACL protection, posing a potential risk for higher ACL injury incidence

THE INFLUENCE OF LOWER LIMB MUSCLE PRE-ACTIVATION ON KNEE JOINT DYNAMIC CONTROL DURING A SINGLE-LEG LANDING TASK IN BADMINTON

Purpose: Lower limb neuromuscular strategies impact knee biomechanics, crucial for ACL injury prevention. Yet, the link between them remains unclear. In our randomized trial with 34 badminton players, we examined lower limb muscle preactivity during single-leg landings. Findings revealed that increased rectus femoris preactivation correlated with heightened knee valgus angle. Moreover, higher lateral hamstring/quadriceps co-contraction ratios predicted increased knee extension moments. These outcomes suggest potential benefits in ACL injury prevention through reduced quadriceps pre-activation and optimal lateral hamstring/quadriceps co-contraction ratios. Understanding these relationships aids in developing targeted prevention strategies for anterior cruciate knee injuries

Investigation on the influential mechanism of FA and GGBS on the properties of CO2-cured cement paste

In the present work, the synergetic effect of fly ash (FA) and ground granulated blast furnace slag (GGBS) on the early compressive strength and microstructure development of CO2-cured mortars was investigated. A rim of several micrometers was found around carbonated cement particles, which contained not only silica-rich gel but also crystal calcium carbonate. The calcium carbonate formed around the cement particles were surrounded by an amorphous layer of around 3 nm, while no layers were observed around the calcite formed on FA or GGBS particles. The calcite formed on FA particles were hexagonal plate shaped, while the one on GGBS particles were rhombohedral shaped. The use of FA resulted in the increase of crystal size and crystallinity of calcite, while GGBS decreased the crystal size of calcite. The incorporation of FA and GGBS increased the calcite content and polymerization of silica-rich gel. However, this didn’t result in a higher compressive strength. This was due to the looser microstructure and nanopores within the carbonation products compared to the pure ordinary Portland cement sample. The compressive strength of the ternary binder system showed linear relationship with capillary pores and the crystal size of calcite. Moreover, the effect of GGBS on the compressive strength reduction was more obvious than that of FA.Investigation on the influential mechanism of FA and GGBS on the properties of CO2-cured cement pastepublishedVersio

TOP-ReID: Multi-spectral Object Re-Identification with Token Permutation

Multi-spectral object Re-identification (ReID) aims to retrieve specific objects by leveraging complementary information from different image spectra. It delivers great advantages over traditional single-spectral ReID in complex visual environment. However, the significant distribution gap among different image spectra poses great challenges for effective multi-spectral feature representations. In addition, most of current Transformer-based ReID methods only utilize the global feature of class tokens to achieve the holistic retrieval, ignoring the local discriminative ones. To address the above issues, we step further to utilize all the tokens of Transformers and propose a cyclic token permutation framework for multi-spectral object ReID, dubbled TOP-ReID. More specifically, we first deploy a multi-stream deep network based on vision Transformers to preserve distinct information from different image spectra. Then, we propose a Token Permutation Module (TPM) for cyclic multi-spectral feature aggregation. It not only facilitates the spatial feature alignment across different image spectra, but also allows the class token of each spectrum to perceive the local details of other spectra. Meanwhile, we propose a Complementary Reconstruction Module (CRM), which introduces dense token-level reconstruction constraints to reduce the distribution gap across different image spectra. With the above modules, our proposed framework can generate more discriminative multi-spectral features for robust object ReID. Extensive experiments on three ReID benchmarks (i.e., RGBNT201, RGBNT100 and MSVR310) verify the effectiveness of our methods. The code is available at https://github.com/924973292/TOP-ReID.Comment: This work is accepted by AAAI202

Characterization of heavy metal contamination in wetland sediments of Bosten lake and evaluation of potential ecological risk, China

In November 2023, twenty-two sediment samples were collected from the Bosten Lake wetland in Xinjiang to determine the concentrations of eight heavy metals: arsenic (As), cadmium (Cd), chromium (Cr), copper (Cu), mercury (Hg), nickel (Ni), lead (Pb), and zinc (Zn). This data was used to assess heavy metal contamination and potential ecological risks in the sediments using the Pollution Load Index (PLI) and the Potential Ecological Risk Index (RI). Additionally, multivariate statistical analysis and Positive Matrix Factorization (PMF) were employed to elucidate potential sources and their contributions to contamination. The following are the main conclusions: (1) average concentrations of Zn, Cd, Cr, Pb, and Hg in the sediments surpassed Xinjiang soil background levels by factors of 1.01, 3.58, 1.32, 1.94, and 1.53, respectively. (2) Sediments demonstrated severe pollution with Cd, slight pollution with Zn, Cr, Pb, and Hg, while Cu and Ni indicated mild pollution and As showed non-polluted levels. The overall PLI average (1.01) suggested slight contamination. (3) The descending order of average single ecological risk values were Cd, Hg, Pb, Cu, Ni, Cr, As, and Zn, with a comprehensive RI averaging at 184.07, signaling a moderate ecological risk. (4) Source apportionment revealed that Zn, Cu, Pb, and Ni were influenced by transportation and household waste emissions, while Cr and As were dictated by natural background levels. Hg predominately originated from fossil fuel combustion and Cd from agricultural activities. (5) Mixed sources accounted for the following percentage contributions to sediment heavy metal content: transportation and domestic waste (30.41%), natural background (25.88%), fossil fuel combustion (22.40%), and agricultural activities (21.31%). With anthropogenic inputs exceeding those of natural origins, it is imperative to prioritize the management of Cd, Hg, and Pb as primary pollutants within the region

Particle Size Distribution and Depth to Bedrock of Chinese Cultivated Soils: Implications for Soil Classification and Management

Although a number of studies have provided information on soil texture, soil classification, and depth to bedrock throughout China, few studies have combined this information, which is the basis for agricultural field management. A total of 81% of China’s cultivated lands are distributed among the Middle–Lower Yangtze Plain (18.2%), arid and semiarid North China Plain (18.2%), Northeast Plain (17%), Huang-Huai-Hai Plain (16.1%), and Yunnan–Guizhou Plateau (11.6%). The Huang-Huai-Hai Plain has the highest density of agricultural land (58.5%) and the greatest depth to bedrock of cultivated land (243–402 m). The lowest cultivated depth to bedrock (4–84 m) is concentrated in the Sichuan Basin and its surrounding regions. The main cultivated soil types are Anthrosols, Fluvisols, Cambisols, Phaeozems, Luvisols, Kastanozems, Leptosols, and Acrisols, under the main topsoil texture classes of loam, clay loam, silty clay loam, silt loam, sandy loam, and clay. The Fluvisols had the largest depth to bedrock (156 m) on the Middle–Lower Yangtze Plain and Huang-Huai-Hai Plain, with the highest silt soil distributions but comparable lower sand contents. The Yunnan–Guizhou Plateau had the highest clay soil content. The cultivation under Kastanozems and Leptosols on the Qinghai–Tibet Plateau and in arid and semiarid North China and under Phaeozems on the Northeast Plain should be restricted and managed very cautiously facing erosion risk. The higher percentages of Anthrosols are on the Middle–Lower Yangtze Plain (37%), in Southern China (32%), and on the Yunnan–Guizhou Plateau (26%). The same cultivation aim (i.e., more crop 0production) has produced a similar range of properties over time among the soils developed on agricultural fields, which are classified as Anthrosols. However, various soil types can still be found in agroecosystems because of the variations in climate and topography. Our results highlight that the agriculture-based soil climate and topography shape the interaction of the soil development and not only the pedogenic history of the soil development under variations in the soil depth to bedrock but also the cultivation of distinct pedogenic features. This study provides cultivated soil information on the depth to bedrock, soil classification, and soil texture in China, as well as instructions for field strategies for sustainable agricultural development