History

EDISON'S ELECTRIC LIGHT: BIOGRAPHY OF AN INVENTION by Robert Friedel, et al. (New Brunswick, NJ: Rutgers University Press, 1986—$27.95 until July 1st, then $35)

ENGINEERS & ELECTRONS: A CENTURY OF ELECTRICAL PROGRESS by John D. Ryder and Donald G. Fink (IEEE Press, 345 East 47th St., New York 10017—price not given)

THE MAKING OF A PROFESSION: A CENTURY OF ELECTRICAL ENGINEERING IN AMERICA by A. Michal McMahon (New York: IEEE Press, see address to left, 1984—price not given)

IBM'S EARLY COMPUTERS by Charles J. Bashe, et al (Cambridge, MA: MIT Press, 1986—$27.50)

THE POWER OF THE PRESS: THE BIRTH OF AMERICAN POLITICAL REPORTING by Thomas C. Leonard (New York: Oxford, 1986—$22.50)     

The effectiveness of front fork systems at damping accelerations during isolated aspects specific to cross-country mountain biking

Cross-country mountain bike suspension reportedly enhances comfort and performance through reduced vibration and impact exposure. This study analysed the effectiveness of three different front fork systems at damping accelerations during the crossing of three isolated obstacles (stairs, drop, and root). One participant completed three trials on six separate occasions in a randomised order using rigid, air-sprung, and carbon leaf-sprung forks. Performance was determined by time to cross obstacles, while triaxial accelerometers quantified impact exposure and damping response. Results identified significant main effect of fork type for performance time (p < 0.05). The air-sprung and leaf-sprung forks were significantly slower than the rigid forks for the stairs (p < 0.05), while air-sprung suspension was slower than the rigid for the root protocol (p < 0.05). There were no differences for the drop protocol (p < 0.05). Rigid forks reduced overall exposure (p < 0.05), specifically at the handlebars for the stairs and drop trials. More detailed analysis presented smaller vertical accelerations at the handlebar for air-sprung and leaf-sprung forks on the stairs (p < 0.05), and drop (p < 0.05) but not the root. As such, it appears that the suspension systems tested were ineffective at reducing overall impact exposure at the handlebar during isolated aspects of cross-country terrain features which may be influenced to a larger extent by rider technique.     

Female athlete endorsers: Determinants of effectiveness

In drawing from social role theory and the match-up hypothesis, the purpose of this study was to determine influential variables regarding the effectiveness of female athlete endorsers. A 2 (gender appropriate/gender inappropriate) × 2 (sport related product/non-sport related product) experiment was conducted with 296 participants from four different universities throughout the United States. Results indicated that type of sport had little effect on credibility measures. Further, the athlete's sport had no effect on athlete-product fit. The most important aspect relative to purchase intentions was the product being endorsed, not the sport in which the athlete competed. Results are discussed in terms of practical implications and theoretical considerations.     

The impact of uphill cycling and bicycle suspension on downhill performance during cross-country mountain biking

ABSTRACT

Non-propulsive work demand has been linked to reduced energetic economy of cross-country mountain biking. The purpose of this study was to determine mechanical, physiological and performance differences and observe economy while riding a downhill section of a cross-country course prior to and following the metabolic “load” of a climb at race pace under two conditions (hardtail and full suspension) expected to alter vibration damping mechanics. Participants completed 1 lap of the track incorporating the same downhill section twice, under two conditions (hardtail and full suspension). Performance was determined by time to complete overall lap and specific terrain sections. Power, cadence, heart rate and oxygen consumption were sampled and logged every second while triaxial accelerometers recorded accelerations (128 Hz) to quantify vibration. No differences between performance times (P = 0.65) or power outputs (P = 0.61) were observed while physiological demand of loaded downhill riding was significantly greater (P < 0.0001) than unloaded. Full suspension decreased total vibrations experienced (P < 0.01) but had no effect on performance (P = 0.97) or physiological (P > 0.05) measures. This study showed minimal advantage of a full suspension bike in our trial, with further investigations over a full race distance warranted.     

THE HIGHER EDUCATION CURRICULUM CRISIS

After presenting data collected from national random samples of administrators and data collected from faculty members in a few selected junior colleges and universities, the authors contend that critics of the undergraduate curriculum may indeed have a basis for their indictments. A set of policy proposals are then presented for consideration.     

Global estimates of the implications of COVID-19-related preprimary school closures for children’s instructional access,development, learning,and economic wellbeing

Observational data collected prior to the pandemic (between 2004 and 2019) were used to simulate the potential consequences of early childhood care and education (ECCE) service closures on the estimated 167 million preprimary-age children in 196 countries who lost ECCE access between March 2020 and February 2021. COVID-19-related ECCE disruptions were estimated to result in 19.01 billion person-days of ECCE instruction lost, 10.75 million additional children falling “off track” in their early development, 14.18 million grades of learning lost by adolescence, and a present discounted value of USD 308.02 billion of earnings lost in adulthood. Further burdens associated with ongoing closures were also forecasted. Projected developmental and learning losses were concentrated in low- and lower middle-income countries, likely exacerbating long-standing global inequities.     

Potentiation of sprint cycling performance: the effects of a high-inertia ergometer warm-up

ABSTRACT

Participant and protocol factors affect post-activation potentiation response. Performance enhancement is more consistent in highly-trained participants following multiple sets of a biomechanically similar conditioning activity. Providing optimal conditions, 6 international-level sprint cyclists executed multiple sets of short maximal conditioning contractions on a high-inertia ergometer before metered sprint performance. Three trial conditions were completed on separate days after a standardised warm-up: dynamic (DYN: 4 × 4 crank-cycles), isometric (ISO: 4 × 5-sec maximal voluntary contraction (MVC)), and control (CON: rest). Performance was measured from standing start to maximum velocity on an inertial-load ergometer at baseline (Pre), 4 (Post4), 8 (Post8) and 16 (Post16) min post-conditioning. Performance and biomechanical measures were assessed across 4 sprint segments, with magnitude-based inferences used to assess the likelihood that any affect was beneficial. Performance time only improved in DYN Post4, a 3.9% reduction during the first crank cycle (92% likely). On the ascending limb of the power-cadence relationship, peak torque and average power increased by 6.2% (94% likely) and 4.0% (87% likely), respectively. In ISOPost16, optimal cadence increased (82% likely) and average power improved over the descending limb (76% likely). DYN and ISO potentiated extremities of the torque-cadence relationship at distinct recovery times post-conditioning. This study suggests merit in including a high-inertia warm-up for sprint cycling.