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R F Freeman

Publications and source records attributed to R F Freeman.

8 recordsLinked to original sources

Using faculty and student perceptions of group dynamics to develop recommendations for PBL training.

BACKGROUND: In training faculty as tutors for problem-based learning (PBL), certain aspects (domains) of teaching methodology are highlighted in the medical education literature. These are content, cognitive processing, and group dynamics. The authors contend that the amounts of attention given to these domains in faculty and student development have not been equal and that group dynamics needs further attention. METHOD: In March 1993 the authors conducted a time-lapse study that involved 27 first-year students and three faculty in three PBL groups at the University of Toronto Faculty of Medicine. The purpose of the study was to determine faculty and student perceptions and knowledge of effective group dynamics, and to develop recommendations for student and faculty training. A qualitative approach was used that combined projective questions, post-tutorial questionnaires, and live and videotaped observations. RESULTS: Observations and analysis of the data revealed a generally low awareness of effective group dynamics and the absence of a mechanism for reflection that could help groups analyze and learn from their behaviors. The results also revealed a discrepancy between self-reported behavior and observed behavior. For example, the students and faculty perceived their groups as generally "working well as a team," but observers noted that several aspects of group productivity (such as the articulation of goals and planning for future sessions) were not addressed. CONCLUSION: The authors recommend that medical schools develop comprehensive training programs to teach group members to evaluate group performance and engage in open discussion of effective and ineffective behaviors.

Attitude↗

Chloramphenicol acetylransferase-independent chloramphenicol resistance in Streptomyces coelicolor A3(2).

Streptomyces coelicolor A3(2) and S. lividans 66, which lack chloramphenicol acetyltraferase, gave rise to vhloramphenicol-sensitive (CmlS) variants spontaneously at frequencies of 0-5 to 2%. The fertility type of S. coelicolor in respect of the SCPI plasmid (SCPI+, SCPI- or NF) had no effect on chloramphenicol sensitivity or on the frequency at which CmlS variants arose. CmlS isolates spontaneously reverted to CmlR at frequencies one to three orders of magnitude lower than the frequency with which CmlS strains arose from CmlR. CmlR revertants obtained spontaneously from CmlS clones again produced CmlS isolates at the normal frequency of several per cent. Therefore, CmlS and CmlR are reversible phenotypes. In crosses between marked CmlR and CmlS S. coelicolor strains, transfer of chloramphenicol resistance into the sensitive strain apparently occurred independently of chromosomal recombination. Mapping experiments excluded the possibility that segregation of a chromosomal locus determines CmlR versus CmlS phenotype. In crosses between SCPI- strains, fertility was not significantly different in CmlR x CmlS, CmlR x CmlR and CmlS x CmlS combinations. Covalently closed circular DNA from CmlS and CmlR strains of S. coelicolor was indistinguishable in molecular weight and restriction endonuclease cleavage pattern. It is suggested that chloramphenicol resistance in S. coelicolor A3(2) is affected by some kind of transposable genetic element that may be capable of extra-chromosomal existence.

Acetyltransferases↗

Osmotic and ionic regulation in different populations of the new zealand freshwater crayfish Paranephrops zealandicus.

1. Some features of the osmoregulatory mechanism are compared in four populations of Paranephrops zeal andicus White collected form freshwaters of different ionic concentrations. 2. Crayfish from freshwaters of ca, 2-0 mM-NaCl concentration show a sustained decrease in blood concentration of ca. 8% when placed in 0-2 mM-NaCl. 3. Populations from freshwaters of ca. 0-2-0-4 mM-NaCl show lower rates of net salt loss in distilled water and higher rates of net salt uptake form dilute NaCl solutions than do populations from freshwaters of ca. 0-8-2-0 mM-NaCl. 4. Renal salt losses over the first 24 h in distilled water account for ca. 18% of the total salt loss. 5. It is suggested that P. zealandicus from environments of lowest concentration shows a similar degree of adaptation to freshwater as do crayfish of the northern hemisphere. It differs in possessing a substantially higher blood concentration.

Animals↗