Browsing by Subject "Developmental"
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Item Elementary students' recognition and analysis of their own singing voices from digital recordings(2006-12) Tryon, April C.; Killian, Janice; Stoune, Michael; Fischer, PeterThe purpose of this study was to assess elementary students' development and ability to recognize and analyze their own singing voices from a consumer quality digital recorder. In this study the first through third grades were chosen to learn and individually record an age-appropriate song chosen from their curriculum. Students then listened to three different voices to determine which one was theirs. Next they listened to their voices again and were asked, "Did you sing the melody correctly?", "Did you sing the rhythm correctly?" and "Did you start on the correct singing note?" Students' self-analysis of their own singing voices were then tested against the researchers analysis of their voices. Results indicated that second and third graders were able to analyze themselves more accurately than first graders. Results also indicated that although only half of the students performed their songs accurately, the majority of them could correctly assess their singing accuracy.Item Multimedia-enhanced developmental mathematics for postsecondary culturally diverse students(2015-12) Belfi, Marcie Merinda; Bryant, Diane Pedrotty; Bryant, Brian R; Sorrells, Audrey M; Powell, Sarah R; Liu, MinStudents who are not ready for college must take developmental courses, predominately in math more than reading or writing, because of the need to pass high school algebra as a prerequisite to gain entrance to college. Students who take developmental courses are predominately from minority ethnic backgrounds or from low- income families. These students often have documented learning disabilities (LD) or have been overlooked by the education system. The use of multimedia in the classroom can offer these students various methods for learning, as well as individualized instruction. The present study compares a multimedia-enhanced (MME) developmental mathematics course that has a mandatory attendance requirement to a course that teaches the same curriculum in a lecture-based format. A mixed-methods comparative analysis pretest posttest quasi-experimental design was used to compare student performance on a posttest and final exam between students taught in the MME section and students taught in the lecture-based section. A course survey was conducted to compare student satisfaction between the two conditions. Interviews were conducted to gather students’ perceptions of the barriers and facilitators to learning in both conditions, as well as to determine students’ past experiences with mathematics learning and their dispositions towards mathematics learning in general. The results showed that there were no statistically significant differences in student performance on the posttest and final exam between the students taught in the MME section and the students taught in the lecture-based section. There was no statistically significant difference in student satisfaction between the two sections. The barriers included the short amount of time for the summer course and lack of technology skills. The facilitators included: (a) helpful instructor, (b) supplementary videos provided by faculty member, (c) collaboration with peers, (d) examples in the software showing how to work the problems, (e) step-by-step instructions, (f) portability of the course, (g) ability to print from the lab, (h) working in the lab, (i) working at own pace, (j) access to the textbook online, and (k) opportunities for practice. These results are discussed in further detail and implications for practice and further research are also considered.Item Reproductive and developmental toxicity of highly energetic compounds in zebrafish (Danio rerio)(Texas Tech University, 2006-08) Mukhi, Sandeep; Patino, Reynaldo; Smith, Ernest E.; Carr, James A.; Anderson, Todd A.; Lee, Vaughan H.There has been growing concern in recent years about a variety of toxicants, some of which are highly energetic in nature, that can affect human and ecosystem health. Highly energetic compounds such as perchlorate and hexahydro-1,3,5-trinitro-1,3,5-triazine (known as RDX) have been reported in various environments worldwide. The ecotoxicological impacts of these chemicals are relatively not fully understood. The overall objective of this study was to access the toxicological effects of these two chemicals on reproduction, development and other activities in a model aquatic organism, the zebrafish (Danio rerio). Perchlorate is a known thyroid-disrupting chemical. Exposure to environmental relevant concentrations of perchlorate caused several pathological alterations in thyroid follicles of zebrafish, which were used to establish novel and sensitive biomarkers of perchlorate exposure (Chapter 1). Namely, angiogenesis and ¡®colloidal T4 ring¡¯ intensity were far more sensitive indicators of thyroid disruption than previous available biomarkers. The developmental toxicity of perchlorate was studied in larval zebrafish (Chapter 2). Exposure to perchlorate at concentrations that inhibited thyroid function affected growth (length) and the sex ratio of exposed populations. Treatment with perchlorate skewed the sex ratio towards females, whereas co-treatment with thyroxine (T4) skewed the sex ratio towards males. This is the first report for teleost fishes indicating that thyroid hormone is involved in the process of gonadal sex determination and differentiation. An effect of perchlorate on the reproductive performance of zebrafish was also observed in a long-term exposure study (Chapter 3). After 16 weeks of exposure to perchlorate, a decline was observed in the level of T4, but not triiodothyronine, in whole-body homogenates of mothers and their embryos. Perchlorate also impaired fecundity (packed-egg volume), although egg diameters were increased and fertilization and hatching rates were unaffected. Analyses of the embryos also indicated impaired growth of jaw-forming cartilages (Meckel¡¯s and ceratohyal). Relatively little information is available concerning the lethal and sublethal effects of RDX in teleosts. The acute toxicity of RDX was determined for larval zebrafish (Chapter 4). The median lethal concentration of RDX was estimated (96-h LC50, 23-26 ppm), and effects on the surviving fish such as vertebral column deformities and behavioral abnormalities were also documented. The chronic toxicity and bioconcentration potential of RDX were subsequently determined in adult zebrafish (Chapter 5). Long-term exposure to RDX caused severe mortality at a concentration of 9.6 ppm. The bioconcentration factor for RDX was low but slightly increased with time of exposure, from ¡Ü1 at 4 and 8 weeks of exposure to >2 at 12 weeks. The RDX metabolite, MNX, was also found in whole-body extracts. Both RDX and MNX were undetectable in whole-body extracts 2 weeks after the fish were transferred to clean water. Lastly, the effects of RDX at sublethal concentrations on reproduction and egg quality were determined (Chapter 6). Exposure to RDX at the relatively low concentration of 0.5 ppm caused a short-lived increase in fecundity within 2 weeks of the onset of exposures; whereas no effects were noted at the higher concentration tested, 3.2 ppm. Egg fertilization rates and embryo hatching rates were unaffected by parental exposures to RDX. It is concluded that exposure to environmental perchlorate and RDX can potentially impact the health of teleosts, an important component of the aquatic biota.Item Reproductive and developmental toxicity of highly energetic compounds in zebrafish (Danio rerio)(2006-08) Mukhi, Sandeep; Patino, Reynaldo; Anderson, Todd A.; Carr, James A.; Lee, Vaughan H.; Smith, Ernest E.There has been growing concern in recent years about a variety of toxicants, some of which are highly energetic in nature, that can affect human and ecosystem health. Highly energetic compounds such as perchlorate and hexahydro-1,3,5-trinitro-1,3,5-triazine (known as RDX) have been reported in various environments worldwide. The ecotoxicological impacts of these chemicals are relatively not fully understood. The overall objective of this study was to access the toxicological effects of these two chemicals on reproduction, development and other activities in a model aquatic organism, the zebrafish (Danio rerio). Perchlorate is a known thyroid-disrupting chemical. Exposure to environmental relevant concentrations of perchlorate caused several pathological alterations in thyroid follicles of zebrafish, which were used to establish novel and sensitive biomarkers of perchlorate exposure (Chapter 1). Namely, angiogenesis and ¡®colloidal T4 ring¡¯ intensity were far more sensitive indicators of thyroid disruption than previous available biomarkers. The developmental toxicity of perchlorate was studied in larval zebrafish (Chapter 2). Exposure to perchlorate at concentrations that inhibited thyroid function affected growth (length) and the sex ratio of exposed populations. Treatment with perchlorate skewed the sex ratio towards females, whereas co-treatment with thyroxine (T4) skewed the sex ratio towards males. This is the first report for teleost fishes indicating that thyroid hormone is involved in the process of gonadal sex determination and differentiation. An effect of perchlorate on the reproductive performance of zebrafish was also observed in a long-term exposure study (Chapter 3). After 16 weeks of exposure to perchlorate, a decline was observed in the level of T4, but not triiodothyronine, in whole-body homogenates of mothers and their embryos. Perchlorate also impaired fecundity (packed-egg volume), although egg diameters were increased and fertilization and hatching rates were unaffected. Analyses of the embryos also indicated impaired growth of jaw-forming cartilages (Meckel¡¯s and ceratohyal). Relatively little information is available concerning the lethal and sublethal effects of RDX in teleosts. The acute toxicity of RDX was determined for larval zebrafish (Chapter 4). The median lethal concentration of RDX was estimated (96-h LC50, 23-26 ppm), and effects on the surviving fish such as vertebral column deformities and behavioral abnormalities were also documented. The chronic toxicity and bioconcentration potential of RDX were subsequently determined in adult zebrafish (Chapter 5). Long-term exposure to RDX caused severe mortality at a concentration of 9.6 ppm. The bioconcentration factor for RDX was low but slightly increased with time of exposure, from ¡Ü1 at 4 and 8 weeks of exposure to >2 at 12 weeks. The RDX metabolite, MNX, was also found in whole-body extracts. Both RDX and MNX were undetectable in whole-body extracts 2 weeks after the fish were transferred to clean water. Lastly, the effects of RDX at sublethal concentrations on reproduction and egg quality were determined (Chapter 6). Exposure to RDX at the relatively low concentration of 0.5 ppm caused a short-lived increase in fecundity within 2 weeks of the onset of exposures; whereas no effects were noted at the higher concentration tested, 3.2 ppm. Egg fertilization rates and embryo hatching rates were unaffected by parental exposures to RDX. It is concluded that exposure to environmental perchlorate and RDX can potentially impact the health of teleosts, an important component of the aquatic biota.