The Teaching Relationship: A Hypothesized Mental Model and Its Consequences

It is proposed that people share a "mental model" of the student-teacher relationship, out of which develop unexamined expectations and attitudes that may be responsible for some long-standing problems of higher education. The model assumes that 1) a knowledge-differential is central to the relationship; 2) the relationship is voluntary, so that both participants must find it rewarding; and 3) both participants are able to play their roles successfully. The first assumption leads to an emphasis on the teacher's expertise and accounts for the importance of research as the chief measure of academic virture. The second allows either participant to assume that the other has initiated the relationship, often leading to frustrated expectations. The third complements the first, implying that "anybody who knows something can teach it," and accounts for both teachers' dissatisfaction with under-prepared students and the widespread failure to recognize differences in teaching skills. Surverydata arepresented on teachers' opinions ofwhat makes students satisfying to teach, providing evidence for the reality of the model's second assumption

Clinical Meaningfulness of the Changes in Muscle Performance and Physical Function Associated With Testosterone Administration in Older Men With Mobility Limitation

Context. Testosterone in Older Men with Mobility Limitations Trial determined the effects of testosterone on muscle performance and physical function in older men with mobility limitation. Trial's Data and Safety Monitoring Board recommended enrollment cessation due to increased frequency of adverse events in testosterone arm. The changes in muscle performance and physical function were evaluated in relation to participant's perception of change. Methods. Men aged 65 years and older, with mobility limitation, total testosterone 100-350 ng/dL, or free testosterone less than 50 pg/mL, were randomized to placebo or 10 g testosterone gel daily for 6 months. Primary outcome was leg-press strength. Secondary outcomes included chest-press strength, stair-climb, 40-m walk, muscle mass, physical activity, self-reported function, and fatigue. Proportions of participants exceeding minimally important difference in study arms were compared. Results. Of 209 randomized participants, 165 had follow-up efficacy measures. Mean (SD) age was 74 (5.4) years and short physical performance battery score 7.7 (1.4). Testosterone arm exhibited greater improvements in leg-press strength, chest-press strength and power, and loaded stair-climb than placebo. Compared with placebo, significantly greater proportion of men receiving testosterone improved their leg-press and chest-press strengths (43% vs 18%, p = .01) and stair-climbing power (28% vs 10%, p = .03) more than minimally important difference. Increases in leg-press strength and stair-climbing power were associated with changes in testosterone levels and muscle mass. Physical activity, walking speed, self-reported function, and fatigue did not change. Conclusions. Testosterone administration in older men with mobility limitation was associated with patient-important improvements in muscle strength and stair-climbing power. Improvements in muscle strength and only some physical function measures should be weighed against the risk of adverse events in this populatio

Testosterone dose-response relationships in hysterectomized women with or without oophorectomy

ObjectiveThis study aims to determine the dose-dependent effects of testosterone on sexual function, body composition, muscle performance, and physical function in hysterectomized women with or without oophorectomy.MethodsSeventy-one postmenopausal women who previously underwent hysterectomy with or without oophorectomy and had total testosterone levels less than 31 ng/dL or free testosterone levels less than 3.5 pg/mL received a standardized transdermal estradiol regimen during the 12-week run-in period and were randomized to receive weekly intramuscular injections of placebo or 3, 6.25, 12.5, or 25 mg of testosterone enanthate for 24 weeks. Total and free testosterone levels were measured by liquid chromatography-tandem mass spectrometry and equilibrium dialysis, respectively. The primary outcome was change in sexual function measured by the Brief Index of Sexual Functioning for Women. Secondary outcomes included changes in sexual activity, sexual distress, Derogatis Interview for Sexual Functioning, lean body mass, fat mass, muscle strength and power, and physical function.ResultsSeventy-one women were randomized; five groups were similar at baseline. Sixty-two women with analyzable data for the primary outcome were included in the final analysis. The mean on-treatment total testosterone concentrations were 19, 78, 102, 128, and 210 ng/dL in the placebo, 3-mg, 6.25-mg, 12.5-mg, and 25-mg groups, respectively. Changes in composite Brief Index of Sexual Functioning for Women scores, thoughts/desire, arousal, frequency of sexual activity, lean body mass, chest-press power, and loaded stair-climb power were significantly related to increases in free testosterone concentrations; compared with placebo, changes were significantly greater in women assigned to the 25-mg group, but not in women in the lower-dose groups. Sexual activity increased by 2.7 encounters per week in the 25-mg group. The frequency of androgenic adverse events was low.ConclusionsTestosterone administration in hysterectomized women with or without oophorectomy for 24 weeks was associated with dose and concentration-dependent gains in several domains of sexual function, lean body mass, chest-press power, and loaded stair-climb power. Long-term trials are needed to weigh improvements in these outcomes against potential long-term adverse effects

Enhancing the performance of memetic algorithms by using a matching-based recombination algorithm

The Number Partitioning Problem (MNP) remains as one of the simplest-to-describe yet hardest-to-solve combinatorial optimization problems. In this paper we use the MNP as a surrogate for several related real-world problems, to test new heuristics ideas. To be precise, we study the use of weightmatching techniques to devise smart memetic operators. Several options are considered and evaluated for that purpose. The positive computational results indicate that - despite the MNP may be not the best scenario for exploiting these ideas - the proposed operators can be really promising tools for dealing with more complex problems of the same family