We report the conceptual inventory results of a large-scale assessment project at a large university. We studied an attempt at introducing materials and instructional methods informed by physics ...education research (PER-informed materials) into a department where most instruction has been traditional and a significant number of faculty are hesitant, ambivalent or even resistant about the introduction of such reforms. The changes were made in the laboratories and recitation sections of the introductory classes, both calculus-based and algebra-based, introducing PER-informed materials and training the teaching assistants in student-centered instructional methods. In addition to the results found in the large lecture classes, we present the results of a small PER-informed, inquiry-based, laboratory-based class that has been taught as a special section of the algebra-based course for about 10 years. The assessment reported in this paper was done using available PER-developed assessment instruments. The results of other assessment instruments used in the project, such as free-response pre- and post-tests, are reported in subsequent papers. The results in this paper inform researchers in PER of the use of PER-informed materials and instructional methods in a department not unified in the introduction and implementation of these materials and the results of the implementation as assessed by PER-based conceptual inventories. We found that our conceptual inventory scores were lower than many results reported elsewhere in the literature. However, we did see a statistically significant increase in the conceptual inventory scores with the implementation of PER-informed laboratories and the use of student-centered pedagogy in the labs and recitations. The increase was much greater, if the lecture instructor also used PER-informed materials.
As part of large-scale assessment project at Texas Tech University, we studied the effect of problem format on students responses to quiz questions. The same problem was written in multiple formats ...and administered as a quiz in the large introductory physics sections in both the algebra-based and calculus-based classes. The formats included multiple-choice (MC) only, MC and free response (FR) and FR only. Variations in the FR wording were also explored. We examined the ability of students to both choose the correct answer and correctly explain their reasoning and show their calculations. We also analyzed the type of written responses the students used to support their answers. We found that a large percentage of the students who chose the correct answer could not support their answer with correct reasoning or calculations.
In order to determine if vertically transmitted porcine circovirus (PCV) has played a role in reproductive failure in pigs in areas of endemic infection, archival fixed tissues were examined by ...polymerase chain reaction (PCR) and immunohistochemistry. Tissues tested were from routine cases of abortion or reproductive failure submitted between 1995 and 1998 to the diagnostic laboratory at the Western College of Veterinary Medicine, Saskatoon. They originated from 29 high-health herds in the provinces of Alberta and Saskatchewan and comprised a total of 36 individual submissions. Porcine circovirus type 1 (PCV1) was not detected by PCR in any submitted tissues. Porcine circovirus type 2 (PCV2) was not detected by PCR or immunohistochemistry in any of the submitted tissue. The effect of extended formalin fixation on the detection of PCV2 by PCR was assessed and fixation for up to one week had no gross effect on sensitivity of detection using this PCR technique. Failure to detect porcine circoviruses in cases of reproductive failure prior to 1999 in areas of endemic infections, suggests that reproductive disease may be a new clinical manifestation of PCV2 infection, and that vertical transmission may not have been the primary mechanism of initial dissemination of the virus in the pig population.
Samples from the cloaca and the ventral skin surface of 67 Nile crocodiles (Crocodylus niloticus) captured in four uninhabited areas at Lake Kariba, Zimbabwe, were cultured for Salmonella. All the ...skin samples tested negative for Salmonella, whereas 18 of 67 (26.9%) cloacal samples grew Salmonella. Significantly more males than females yielded Salmonella, but no statistically significant correlation among salmonella carriage, body size, and age was recorded. Ten different serotypes of S. enterica belonging to the subspecies enterica, salamae, and diarizonae were isolated. All isolates belonging to subspecies enterica displayed invasive properties in an experimental mouse model and thus exhibited pathogenic potential, whereas none of the other isolates were invasive. In general, isolates were sensitive to a number of commonly used antimicrobials, except for three isolates that were resistant to streptomycin.
OBJECTIVE: To assess the impact on mortality related to pregnancy of supplementing women of reproductive age each week with a recommended dietary allowance of vitamin A, either preformed or as beta ...carotene. DESIGN: Double blind, cluster randomised, placebo controlled field trial. SETTING: Rural southeast central plains of Nepal (Sarlahi district). SUBJECTS: 44 646 married women, of whom 20 119 became pregnant 22 189 times. INTERVENTION: 270 wards randomised to 3 groups of 90 each for women to receive weekly a single oral supplement of placebo, vitamin A (7000 micrograms retinol equivalents) or beta carotene (42 mg, or 7000 micrograms retinol equivalents) for over 31/2 years. MAIN OUTCOME MEASURES: All cause mortality in women during pregnancy up to 12 weeks post partum (pregnancy related mortality) and mortality during pregnancy to 6 weeks postpartum, excluding deaths apparently related to injury (maternal mortality). RESULTS: Mortality related to pregnancy in the placebo, vitamin A, and beta carotene groups was 704, 426, and 361 deaths per 100 000 pregnancies, yielding relative risks (95% confidence intervals) of 0. 60 (0.37 to 0.97) and 0.51 (0.30 to 0.86). This represented reductions of 40% (P<0.04) and 49% (P<0.01) among those who received vitamin A and beta carotene. Combined, vitamin A or beta carotene lowered mortality by 44% (0.56 (0.37 to 0.84), P<0.005) and reduced the maternal mortality ratio from 645 to 385 deaths per 100 000 live births, or by 40% (P<0.02). Differences in cause of death could not be reliably distinguished between supplemented and placebo groups. CONCLUSION: Supplementation of women with either vitamin A or beta carotene at recommended dietary amounts during childbearing years can lower mortality related to pregnancy in rural, undernourished populations of south Asia.
High quality learning is extensive, well integrated, deep, and supports the use of knowledge in new situations that require adaptation of what has been learned previously. This book reviews current ...research on the nature of high quality learning and the factors that facilitate or inhibit it. The book addresses relationships between quality of learning and learners' dispositions, teaching methods, cognitive strategies, assessment and technologies that can support learning. The chapters provide theoretical analyses, reports of classroom research, and suggestions for practical application for both teachers and learners. The book will be of value to teachers at all levels of education and provides guidance for students about how to approach classroom tasks in order to develop high quality learning.
Vitamin A deficiency is associated with stunting and wasting in preschool children, but vitamin A supplementation trials have not shown a consistent effect on growth.
We examined the effect of ...vitamin A supplementation on height and weight increments among Indonesian preschool children.
Data were obtained from a randomized, double-masked, placebo-controlled trial of rural Javanese children aged 6–48 mo. Children received 206000 IU vitamin A (103000 IU if aged <12 mo) or placebo every 4 mo.
High-dose vitamin A supplementation modestly improved the linear growth of the children by 0.16 cm/4 mo. The effect was modified by age, initial vitamin A status, and breast-feeding status. Vitamin A supplementation improved height by 0.10 cm/4 mo in children aged <24 mo and by 0.22 cm/4 mo in children aged ≥24 mo. The vitamin A–supplemented children with an initial serum retinol concentration <0.35 μmol/L gained 0.39 cm/4 mo more in height and 152 g/4 mo more in weight than did the placebo group. No growth response to vitamin A was found among children with an initial serum retinol concentration ≥0.35 μmol/L. In non-breast-fed children, vitamin A supplementation improved height by 0.21 cm/4 mo regardless of age. In breast-fed children, vitamin A supplementation improved linear growth by ≈0.21 cm/4 mo among children aged ≥24 mo, but had no significant effect on the growth of children aged <24 mo.
High-dose vitamin A supplementation improves the linear growth of children with very low serum retinol and the effect is modified by age and breast-feeding.
Working Paper No. 25969 Severe environmental shocks have grown in frequency and intensity due to climate change. Can policy protect against the often devastating human impacts of these shocks, ...particularly for vulnerable populations? We study this question by leveraging data from a situation in which a tornado tore through an area involved in a double-blind cluster-randomized controlled trial of at-birth vitamin A supplementation in Bangladesh. Tornado exposure in utero and in infancy decreased birth size and physical growth, and increased the incidence of severe fevers. But infants who received vitamin A supplementation, which boosts immune system functioning, were protected from these effects. Tornado impacts and protective effects were both substantially larger for boys. Our results suggest that wide-scale supplementation policies would generate potential health benefits in disaster-prone areas of low-income countries.
Wheat flour is a possible food vehicle for vitamin A fortification.
This study assessed the efficacy of consumption of a vitamin A–fortified wheat-flour bun (pandesal) on the vitamin A status of ...school-age children.
This was a double-masked clinical trial conducted in 396 and 439 children aged 6–13 y attending 4 rural schools in the Philippines. The children were randomly assigned to a vitamin A–fortified (experimental) or nonfortified (control) group. A 60-g vitamin A–fortified pandesal (containing ≈133 μg retinol equivalents) or a nonfortified pandesal was consumed by the children 5 d/wk for 30 wk. Vitamin A status, hemoglobin concentration, anthropometric status, morbidity, and dietary intake were assessed at baseline and 30 wk later. A modified relative dose response (MRDR) was assessed in a subsample of 20% of the children (≈75/group) with the lowest initial serum retinol concentration at the 30-wk follow-up.
Baseline serum retinol significantly modified the effect of the intervention. The fortified group, whose initial serum retinol concentrations were below the median, had a 0.07 ± 0.03-μmol/L greater improvement in serum retinol at the 30-wk follow-up than did the control group (P = 0.02). Improved vitamin A status was also evident in the MRDR subsample. End-of-study differences in the MRDR showed that vitamin A– fortified pandesal intake decreased the percentage of children with inadequate liver vitamin A stores by 50% (15.3% compared with 28.6%; P = 0.05).
Daily consumption of vitamin A–fortified pandesal significantly improved the vitamin A status of Filipino school-age children with marginal-to-low initial serum retinol concentrations.
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