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971.
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
972.
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
973.
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
974.
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
975.
Shahron Williams van Rooij 《Education and Information Technologies》2007,12(4):191-209
As institutions of Higher Education try to balance limited resources with the rising costs of technology, some institutions
are turning to Open Source software for campus-wide applications such as course management systems and portals. The assumption
is that Open Source will provide the flexibility to build pedagogically sound learning environments while increasing technology
efficiencies. This paper outlines the current state of Open Source software deployment in US Higher Education based on a survey
of 772 Chief Academic Officers and Chief Information Officers conducted in 2006. The results indicate that Carnegie classification
is a critical differentiator of awareness, adoption, and perceptions of Open Source software applications, with perceived
cost of ownership being the key driver of Open Source adoption. Moreover, the study shows that institutions have made little
progress in the development of polices and procedures for Open Source regulatory compliance and security. The study serves
as a baseline for future research into the conditions for successful use of Open Source for supporting integrated learning
environments that deliver campus-wide efficiencies.
Shahron Williams van Rooij is Assistant Professor of Instructional Technology at George Mason University with a focus on the university’s e-Learning Certificate Program. She holds a Ph.D. in Quantitative Methods in the Social Sciences from the City University of New York and has just completed a second doctorate in Instructional Technology and Software Information Systems at George Mason University. As a Certified Distance Education Professional (C.D.E.P.) credentialed by Texas A&M University, she is a frequent speaker on the development of Web-based education and has published in a variety of journals such as the WebNet Journal, the Journal of Interactive Learning Research, the Journal of Modern Business, the Marketing Research Review and the Journal of Research on Technology in Education. Prior to joining GMU, she was the Director of Marketing at Datatel, Inc., in Fairfax, VA, where she facilitated the engineering of new e-learning technology solutions. 相似文献
Shahron Williams van RooijEmail: |
Shahron Williams van Rooij is Assistant Professor of Instructional Technology at George Mason University with a focus on the university’s e-Learning Certificate Program. She holds a Ph.D. in Quantitative Methods in the Social Sciences from the City University of New York and has just completed a second doctorate in Instructional Technology and Software Information Systems at George Mason University. As a Certified Distance Education Professional (C.D.E.P.) credentialed by Texas A&M University, she is a frequent speaker on the development of Web-based education and has published in a variety of journals such as the WebNet Journal, the Journal of Interactive Learning Research, the Journal of Modern Business, the Marketing Research Review and the Journal of Research on Technology in Education. Prior to joining GMU, she was the Director of Marketing at Datatel, Inc., in Fairfax, VA, where she facilitated the engineering of new e-learning technology solutions. 相似文献
976.
Gabriele Kucsko-Stadlmayer 《Zeitschrift für Hochschulrecht, Hochschulmanagement und Hochschulpolitik: zfhr》2007,6(1):8-17
Trotz hoher Studentinnen- und Absolventinnenzahlen in den meisten Studienrichtungen ist der Anteil der Frauen an akademischen Spitzenpositionen noch immer gering. Die Gründe für dieses Missverhältnis liegen in einer Reihe spezifischer Schwierigkeiten, mit denen Frauen bei universitären Laufbahnen konfrontiert sind. Die Politik der Europäischen Union verfolgt seit 1999 das explizite Ziel, Frauen stärker in der universitären und außeruniversitären Forschung zu verankern. Mit dem Vertrag von Amsterdam wurde auch der gemeinschaftsrechtliche Rahmen neu gestaltet. Das UG 2002 hat "Frauenförderung" und "Gleichstellung von Frauen und Männern" zur Aufgabe der Universitäten und damit zu einem zentralen Teil ihres Bildungsauftrags erklärt. Die Europäische Strategie des "Gender Mainstreaming" wurde so in eine innerstaatliche, alle Universitätsorgane bindende Verpflichtung umgesetzt. Der Beitrag behandelt die rechtlichen Möglichkeiten der vollrechtsfähigen Universitäten zur Frauenförderung und bewertet Reichweite und Wirksamkeit der neuen Rechtslage. 相似文献
977.
Liu GF Zhou HK Hu H Zhu ZH Hayat Y Xu HM Yang J 《Journal of Zhejiang University. Science. B》2007,8(12):860-866
Brix weight per stool (BW) of sugarcane is a complex trait, which is the final product of a combination of many components. Diallel cross experiments were conducted during a period of two years for BW and its five component traits, including stalk diameter (SD), stalk length (SL), stalk number (SN), stalk weight (SW), and brix scale (BS) of sugarcane. Phenotypic data of all the six traits were analyzed by mixed linear model and their phenotype variances were portioned into additive (A),dominance (D), additive×environment interaction (AE) and dominance×environment interaction (DE) effects, and the correlations of A, D, AE and DE effects between BW and its components were estimated. Conditional analysis was employed to investigate the contribution of the components traits to the variances of A, D, AE and DE effects of BW. It was observed that the heritabilities of BW were significantly attributed to A, D and DE by 23.9%, 30.9% and 28.5%, respectively. The variance of A effect for BW was significantly affected by SL, SN and BS by 25.3%, 93.7% and 17.4%, respectively. The variances of D and DE effects for BW were also significantly influenced by all the five components by 5.1%~85.5%. These determinants might be helpful in sugarcane breeding and provide valuable information for multiple-trait improvement of BW. 相似文献
978.
Shalini M Yogeeswari P Sriram D Induja S 《Journal of Zhejiang University. Science. B》2007,8(1):45-55
Objective: To study the effect of halo substitution on disubstituted aryl semicarbazones on the anticonvulsant potential and model the activity based on quantum mechanics. Methods: A series of twenty-six compounds of N^4-(4-bromo-3-methylphenyl) semicarbazones were synthesized and evaluated for the anticonvulsant activity in the maximal electroshock seizure (MES) and subcutaneous pentylenetetrazole (scPTZ) seizure threshold tests. Some potential compounds were also tested in the subcutaneous strychnine (scSTY) and subcutaneous picrotoxin (scPIC) seizure threshold tests. The synthesized compounds were tested for behavioral impairment and CNS (central nervous system) depression in mice. Quantum mechanical modelling was carried out on these compounds to gain understanding on the structural features essential for activity. Results: Some compounds possessed broad spectrum anticonvulsant activity as indicated by their effect in pentylenetetrazole, strychnine, picrotoxin and maximal electroshock seizures models in resemblance to other aryl semicarbazone derivatives reported earlier. The higher the difference in HOMO (highest occupied molecular orbital) and LUMO (lowest unoccupied molecular orbital) energy levels was, the greater was the activity profile. Conclusion: The pharmacophoric requirements for compounds to exhibit anticonvulsant activity that includes one aryl unit in proximity to a hydrogen donor-acceptor domain and an electron donor have been justified with the molecular orbital surface analysis of the synthesized compounds. 相似文献
979.
Comparison of high order aberration after conventional and customized ablation in myopic LASIK in different eyes of the same patient 总被引:4,自引:0,他引:4
Purpose: To verify whether there exists any difference in higher order aberrations after undergoing myopic LASIK (laser in situ keratomileusis) with conventional ablation and customized ablation in different eyes of the same patient. Methods: This was a prospective randomized study of 54 myopic eyes (27 patients) that underwent LASIK using the Nidek EC-5000 ex-cimer laser system (Nidek, Gamagori, Japan). Topography-guided customized aspheric treatment zone (CATz) was used in the first eye of the patient (study group) and the other eye of the same patient was operated on with conventional ablation (control group). Higher order aberrations [root-mean-square (RMS) in the 5-mm zone] of both groups were observed with the Nidek OPD-Scan aberrometer before and 3 months after LASIK. Preoperative mean refractive error was similar between two eyes of the same patient (t=?0.577, P>0.05). Results: Preoperatively, higher order aberrations (RMS in the 5-mm zone) in the CATz ablation and conventional groups were (0.3600±0.0341) μm and (0.2680±0.1421) μm, respectively. This difference was not statistically significant (t=1.292, P>0.05). Three months after LASIK, higher order aberrations (RMS in 5-mm zone) in the CATz ablation and conventional groups were (0.3627±0.1510) μm and (0.3991±0.1582) μm, respectively. No statistically significant difference was noted between pre- and postoperative higher order aberrations in the CATz group (t=?0.047, P>0.05). However, a statistically significant increase in higher order aberrations was observed after conventional ablation (t=?5.261, P<0.05). A statistically sig-nificant difference was noted in the increase of higher order aberrations after LASIK between groups (t=?2.050, P=0.045). Con-clusion: LASIK with conventional ablation and topography-guided CATz ablation resulted in the same BSCVA (best specta-cle-corrected visual acuity) 3 month after LASIK. Higher order aberrations were increased, but the increase of higher order ab-errations after customized ablation treatment was less than that after conventional ablation. 相似文献
980.
INTRODUCTION Recently discovered as an endocrine organ, adi-pose tissue can secrete many cytokines such as Re-sistin, adiponectin and free fatty acids, and receives much attention in the study of insulin resistance and type 2 diabetes mellitus (T2DM). As a peptide hor-mone secreted by adipocyte, Resistin is considered to be the linkage between obesity and insulin resistance (Steppan et al., 2001). Most studies on Resistin in-vestigate adipose tissue. In this experiment we de-tected t… 相似文献