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K Bercovitz

Publications and source records attributed to K Bercovitz.

11 recordsLinked to original sources
PubMed1995

Shifting students and faculty to a PBL curriculum: attitudes changed and lessons learned.

BACKGROUND: The University of Toronto Faculty of Medicine is implementing a new undergraduate curriculum that emphasizes active, self-directed learning. The aims of this study were to (1) evaluate shifts in students' attitudes after initial direct experience with problem-based learning (PBL), (2) describe faculty experiences, and (3) develop guidelines for further implementation of PBL. METHOD: Questionnaires were administered at the beginning of the first PBL session and at the close of the last session (five weeks later) to the 250 second-year students in 1992-93 and to their 15 faculty tutors. Quantitative data were analyzed using multivariate analysis of variance and univariate tests. Open-ended questions were categorized based on common patterns that emerged. RESULTS: Of the 250 students, 196 (78%) responded to the pretest, and 207 (83%) responded to the posttest. There was a statistically significant shift in the students' perceptions from pretest to posttest in agreeing that PBL is more effective than traditional teaching methods (increasing from 38% to 52%). The students rated traditional methods as better for knowledge acquisition, whereas PBL methods were rated better for improving teamwork and doctor-patient relationships. At pretest, the most common themes concerned a perceived danger that PBL would result in knowledge gaps, reinforce the wrong information, and make inefficient use of valuable time. Perceived advantages of PBL included that it is more stimulating and enjoyable, and it teaches students how to learn rather than to memorize. At posttest, there was an increase in favorable comments by the students. Virtually all of the attitudes expressed by the students were shared by the faculty. In addition, at pretest the faculty were anxious about the perceived lack of structure in PBL. CONCLUSION: Direct experience with PBL led to more favorable attitudes among the students and faculty. Recommendations are suggested for other schools and programs seeking to implement PBL curricula.

Adult↗
PubMed1993

Low lead level in teeth in Israel.

A total of 180 sound teeth extracted from people living mainly in Northern Israel and some in the center of the country, aged 14-75 years, were analysed by graphite furnace atomic absorption spectrophotometer. The average lead level in teeth roots ranged between 1.61-25.72 micrograms/g dry root, according to the donor's age. This low level was measured in all the regions which were checked, with no significant differences between them, despite differences in levels of motor traffic rates. Based on the low lead level in teeth, we assume that no further reduction in the lead level in gasoline is needed, as long as motorization rate or gasoline consumption does not change significantly.

Adolescent↗
PubMed1992

Systemic lead absorption in human tooth roots.

One-hundred and five impacted and erupted sound teeth were analysed for lead content by graphite furnace atomic absorption spectrophotometry. The results showed that lead accumulated before eruption, presumably soon after the onset of dentine formation. The accumulation in dentine was systemic, without any contribution from the oral environment. The amount of lead in dentine may denote the amount of absorption into the body and serve as a precise index to body burden as no absorption from the mouth can take place. In adults, impacted and erupted teeth can be used together in any research and the donor's age can be considered as the period of lead accumulation.

Absorption↗
PubMed1991

Lead accumulation in teeth of patients suffering from gastrointestinal ulcers.

Thirty-five permanent teeth were analyzed for lead by graphite furnace atomic absorption spectrophotometry. The lead level in the dentine of gastrointestinal ulcer patients, even long after recovery, was significantly higher than that of healthy people (75.02 +/- 8.15 and 25.62 +/- 10.15 ppm, respectively; P less than 0.001). Presumably, massive absorption is possible due to damage to the epithelial mucosal cells of the gastrointestinal tract. In polluted areas, ulcer patients will suffer considerably more than non-ulcerous patients. Moreover, if the same lead level is found in the bones, there is a possible risk that, in elderly people or in patients suffering from osteoporosis, lead will be discharged into the blood and cause lead intoxication.

Adult↗
PubMed1991

Age and gender influence on lead accumulation in root dentine of human permanent teeth.

143 permanent teeth of individuals aged 14-60 yr from a non-occupationally exposed population in northern Israel were analysed for lead accumulation in a atomic absorption spectrophotometer graphite-furnace. A significant correlation was established between lead level and age. No gender correlation was found. The results suggest that any study dealing with lead accumulation in different populations has to compare groups of the same age range, ignoring the sex of the individuals.

Adolescent↗
PubMed1990

Tooth type as indicator of exposure to lead of adults and children.

One hundred and forty-two teeth of children and adults were analysed for lead content by graphite furnace atomic absorption spectrophotometry. The results showed that, for children, tooth age is an important factor that has to be taken into consideration when lead levels are evaluated. In adults tooth type may be ignored, as it is not a major factor affecting lead accumulation.

Adolescent↗
PubMed1989

Magnesium and manganese uptake, accumulation and regulation by a terrestrial isopod, Porcellio spinicornis Say (Porcellionidae, isopoda, Crustacea).

Highest Mg concentration in whole intermoult, 7th growth-stage Porcellio spinicornis, exposed for 7 days to various Mg [367.39 ppb (carrot powder-control), 217.6 ppb (apple powder-control), 100, 150, 500, and 1000 ppm Mg, as well as two mixtures containing 500 ppm Mn + 150 ppm Mg and 500 ppm Mg + 500 ppm Mn)], and Mn concentrations [97.9 ppb (carrot powder-control), 2.0 ppb (apple powder-control), 100, 150, 500 and 1000 ppm)], was observed in males feeding on 500 ppm Mn + 150 ppm Mg, and lowest in females on 500 ppm dietary Mg. Highest tissue Mn concentration, on the other hand, was observed in males exposed to 1000 ppm dietary Mn, and lowest in females on 500 ppm Mg. Approximately 42% of the total tissue Mg was present in hepatopancreas and the remaining in other body tissues, including exoskeleton. In contrast, 78.55% Mn was stored in hepatopancreas and 21.4% in remaining body tissues. Differences between hepatopancreatic Mg levels were not significant between the two sexes, but differences in Mn levels between males and females were significant at P less than 0.01.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMedDate not supplied

Lead levels in teeth of long date and new immigrants in several cities in Israel--preliminary results.

Teeth extracted from 98 people aged 18-77 yr, living in the urban Haifa Bay area or in rural kibbutzim (communal farms) in northern and north-central Israel were analyzed with a graphite furnace atomic absorption spectrophotometer. There were no significant differences in lead levels in teeth for the same age ranges between urban and rural areas, despite differences in motorization rates. We assume that the daily mobility of the residents, the short distances between settlements, and the common origin of their food have a greater effect on the lead level in teeth than do differences in environmental lead in areas of low pollution. New immigrants from Ethiopia and people originating from India and Yemen have lower lead levels in teeth than long date immigrants, but due to different factors. On the other hand, immigrants from Argentina have higher lead levels in teeth in comparison with long date immigrants.

Adult↗