Primigravid and multigravid women: prenatal perspectives     

Nichols MR  Roux GM  Harris NR 《The Journal of perinatal education》2007,16(2):21-32

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Focus-on-form instructional methods promote deaf college students' improvement in English grammar     

Berent GP  Kelly RR  Aldersley S  Schmitz KL  Khalsa BK  Panara J  Keenan S 《Journal of deaf studies and deaf education》2007,12(1):8-24

Focus-on-form English teaching methods are designed to facilitate second-language learners' noticing of target language input, where "noticing" is an acquisitional prerequisite for the comprehension, processing, and eventual integration of new grammatical knowledge. While primarily designed for teaching hearing second-language learners, many focus-on-form methods lend themselves to visual presentation. This article reports the results of classroom research on the visually based implementation of focus-on-form methods with deaf college students learning English. Two of 3 groups of deaf students received focus-on-form instruction during a 10-week remedial grammar course; a third control group received grammatical instruction that did not involve focus-on-form methods. The 2 experimental groups exhibited significantly greater improvement in English grammatical knowledge relative to the control group. These results validate the efficacy of visually based focus-on-form English instruction for deaf students of English and set the stage for the continual search for innovative and effective English teaching methodologies.  相似文献   

Temporal integration in Pavlovian appetitive conditioning in rats     

Leising KJ  Sawa K  Blaisdell AP 《Learning & behavior》2007,35(1):11-18

We used an appetitive sensory preconditioning procedure to investigate temporal integration in rats in two experiments. In Phase 1, rats were presented with simultaneous compound trials on which a 10-sec conditioned stimulus (CS) X was embedded within a 60-sec CS A. In Group Early, CS X occurred during the early portion of CS A, whereas in Group Late, CS X occurred during the latter portion of CS A. In Phase 2, CS X was paired simultaneously with sucrose. On a subsequent test with CS A, the rate of magazine entries peaked during the early portions of the stimulus in Group Early and during the latter portions of the stimulus in Group Late (Experiments 1 and 2). Similar response peaks were not observed on tests with a control stimulus that had been presented in compound with a stimulus that did not signal reward (Experiment 2).  相似文献   

Flavor-evaluative conditioning is unaffected by contingency knowledge during training with color-flavor compounds     

Dickinson A  Brown KJ 《Learning & behavior》2007,35(1):36-42

In two experiments, participants inspected and drank a series of drinks, half of which contained sugar and half unpalatable Tween20 (tween). Each sugar and tween drink had a particular flavor and color. Following this training, the flavors of the sugar drinks were assigned higher hedonic evaluations than were those of the tween drinks, even though the participants did not reliably report which flavors had been present in the sugar and tween drinks during training. Moreover, the evaluative conditioning of the flavors was unaffected by whether or not the colors alone had been pretrained to predict the presence of sugar or tween in the drinks. In accord with Baeyens, Eelen, van den Bergh, and Crombez (1990), we conclude that flavor-evaluative conditioning is not mediated by contingency learning.  相似文献   

Maintenance of responding when reinforcement becomes delayed     

Costa DS  Boakes RA 《Learning & behavior》2007,35(2):95-105

In four experiments with rats, we examined the persistence of behavior when reinforcement was switched from immediate to delayed. In Experiment 1, lever pressing elicited by instrumental training with immediate reinforcement continued when a 20-sec delay of reinforcement was introduced (easy-to-hard condition), whereas when the delay condition was introduced from the start (hard-to-hard condition), responding remained low throughout. A similar result was obtained in Experiment 2, in which lever pressing was elicited by a classical conditioning (autoshaping) procedure. In Experiment 3, rats initially trained with delayed reinforcement continued to respond at a low rate when switched to immediate reinforcement (hard-to-easy condition). By measuring magazine entry (goal tracking) as well as lever pressing (sign tracking) in Experiment 4, we confirmed that such transfer effects at least partly involve the persistence of whatever type of behavior was initially dominant.  相似文献   

Interactions between retroactive-interference and context-mediated treatments that impair Pavlovian conditioned responding     

Wheeler DS  Miller RR 《Learning & behavior》2007,35(1):27-35

In Pavlovian fear conditioning, context-mediated decrements in conditioned responding (e.g., the US preexposure effect) can counteract competition between cues trained together (e.g., overshadowing). Two experiments were conducted using rats in a conditioned lick suppression preparation to determine whether context-mediated competition also counteracts competition between cues trained separately (retroactive interference, or RI). In Experiment 1, a combination of degraded contingency and RI treatments produced less of a decrement in conditioned responding than did either of those treatments alone. Experiment 2 showed that RI treatment attenuates the normally deleterious effect of trial massing. The results suggest that empirical similarities are shared by interference between cues trained apart and competition between cues trained together.  相似文献   

Qualitative and quantitative analysis of goat ovaries,follicles and oocytes in view of in vitro production of embryos     

Islam MR  Khandoker MA  Afroz S  Rahman MG  Khan RI 《Journal of Zhejiang University. Science. B》2007,8(7):465-469

Goat ovaries were collected from the slaughterhouse and categorized as right, left, corpus luteum （CL）-present and -absent group and evaluated on the basis of weight （g）, length （cm）, width （cm）, number of follicles, follicles aspirated and number and state ofcumulus-oocyte-complexes （COCs）. Comparatively higher weight [（0.66±0.02） vs （0.64±0.02） g], length [（1.17±0.02） vs （1.1 ±0.02） cm] and width [（0.77±0.02） vs （0.74±0.02） cm] were found in right ovaries than those of left. On the other hand significantly （P〈0.05） higher weight [（0.71±0.03） vs （0.64±0.01） g] and width [（0.76±0.03） vs （0.75±0.01） cm] were found in CL-present group than those of CL-absent group of ovaries. The left ovaries contained comparatively higher number of normal COCs [（1.06±0.09） per ovary] than fight ovaries [（1.03±0.10） per ovary] and the similar trend was found in total number of follicles [（4.51±0.25） vs （4.30±0.23） per ovary] and follicles aspirated [（2.55±0.14） vs （2.52±0.12） per ovary]. But the total COCs per ovary was almost similar in both ovaries [right and left： （1.85±0.12） and （1.85±0.11） per ovary, respectively]. Higher number of total COCs [（1.87±0.09） vs （1.76±0.16） per ovary], total number of follicles [（4.45±0.19） vs （4.16±0.37） per ovary], follicles aspirated [（2.55±0.10） vs （2.48±0.21） per ovary] and normal COCs [（1.12±0.07） vs （0.76±0.14） per ovary] were found in CL-absent group than those of CL-present group of ovaries.  相似文献   

The learning environment in clicker classrooms: student processes of learning and involvement in large university‐level courses using student response systems     

April R. Trees 《Learning, Media and Technology》2007,32(1):21-40

To explore what social and educational infrastructure is needed to support classroom use of student response systems (Roschelle et al., 2004 Roschelle, J., Penuel, W. R. and Abrahamson, L. 2004. “The networked classroom”. In Educational Leadership 6150–54.  [Google Scholar]), this study investigated the ways in which student characteristics and course design choices were related to students’ assessments of the contribution of clicker use to their learning and involvement in the classroom. Survey responses of over 1500 undergraduates enrolled in seven large enrollment ‘clicker courses’ offered by three university departments are analyzed. A number of factors contribute to students’ positive perception of clickers: a desire to be involved and engaged, a view that traditional lecture styles are not best, valuing of feedback, class standing, previous experience with lecture courses, anticipated course performance, and amount of clicker use in the classroom. These results underscore the importance of considering social and communication elements of the classroom when adopting student response technology.  相似文献   

Supplemental instruction in introductory biology I: enhancing the performance and retention of underrepresented minority students     

Rath KA  Peterfreund AR  Xenos SP  Bayliss F  Carnal N 《CBE life sciences education》2007,6(3):203-216

Supplemental instruction classes have been shown in many studies to enhance performance in the supported courses and even to improve graduation rates. Generally, there has been little evidence of a differential impact on students from different ethnic/racial backgrounds. At San Francisco State University, however, supplemental instruction in the Introductory Biology I class is associated with even more dramatic gains among students from underrepresented minority populations than the gains found among their peers. These gains do not seem to be the product of better students availing themselves of supplemental instruction or other outside factors. The Introductory Biology I class consists of a team-taught lecture component, taught in a large lecture classroom, and a laboratory component where students participate in smaller lab sections. Students are expected to master an understanding of basic concepts, content, and vocabulary in biology as well as gain laboratory investigation skills and experience applying scientific methodology. In this context, supplemental instruction classes are cooperative learning environments where students participate in learning activities that complement the course material, focusing on student misconceptions and difficulties, construction of a scaffolded knowledge base, applications involving problem solving, and articulation of constructs with peers.  相似文献   

Teaching without a textbook: strategies to focus learning on fundamental concepts and scientific process     

Klymkowsky MW 《CBE life sciences education》2007,6(3):190-193