Validation of a single-stage submaximal treadmill walking test

Abstract

The single-stage treadmill walking test of Ebbeling et al. is commonly used to predict maximal oxygen consumption ([Vdot]O_2max) from a submaximal effort between 50% and 70% of the participant's age-predicted maximum heart rate. The purpose of this study was to determine if this submaximal test correctly predicts [Vdot]O_2max at the low (50% of maximum heart rate) and high (70% of maximum heart rate) ends of the specified heart rate range for males and females aged 18 – 55 years. Each of the 34 participants completed one low-intensity and one high-intensity trial. The two trials resulted in significantly different estimates of [Vdot]O_2max (low-intensity trial: mean 40.5 ml · kg^?1 · min^?1, s = 9.3; high-intensity trial: 47.5 ml · kg^?1 · min^?1, s = 8.8; P < 0.01). A subset of 22 participants concluded their second trial with a [Vdot]O_2max test (mean 47.9 ml · kg^?1 · min^?1, s = 8.9). The low-intensity trial underestimated (mean difference = ?3.5 ml · kg^?1 · min^?1; 95% CI = ?6.4 to ?0.6 ml · kg^?1 · min^?1; P = 0.02) and the high-intensity trial overestimated (mean difference = 3.5 ml · kg^?1 · min^?1; 95% CI = 1.1 to 6.0 ml · kg^?1 · min^?1; P = 0.01) the measured [Vdot]O_2max. The predictive validity of Ebbeling and colleagues' single-stage submaximal treadmill walking test is diminished when performed at the extremes of the specified heart rate range.     

Infant Affective Reactions to the Resumption of Maternal Interaction after the Still-Face

To investigate infants' reactions to the Face-to-Face Still-Face Paradigm and in particular the reunion episode, 50 6-month-olds' affective, behavioral, and physiologic reactions were recorded and analyzed. Infants reacted to the still-face with negative affect, a drop in vagal tone, and an increase in heart rate. By contrast, they reacted to the reunion episode with a mixed pattern of positive and negative affect. There was a carryover of negative affect from the still-face, an increase in fussiness and crying, and a rebound of positive affect. During this episode, the infants' heart rate and vagal tone returned to initial levels. The data indicate that infant affective displays are specifically related to different interactive events, but that their physiologic reactions do not show the same level of specificity. The findings also highlight the complexity of the affective and reparatory processes that take place in mother-infant interactions.     

Neuropsychology of Early-treated Phenylketonuria: Specific Executive Function Deficits

This study explored the hypothesis that children with early-treated phenylketonuria (PKU) are selectively impaired on executive function measures, even when still on diet. The rationale for this hypothesis is that even mild elevations in phenylalanine (Phe) can lead to lower central levels of biogenic amines, including dopamine (DA). We hypothesize that this mild DA depletion causes subtle prefrontal dysfunction, which in turn affects executive functions such as set maintenance, planning, and organized search. 11 preschool early-treated PKU children (M age = 4.64) and a sample of age- and IQ-matched unaffected peers (n = 11) were evaluated on a battery of executive function (EF) measures. In addition, a "non-executive function" task, recognition memory, was administered to all subjects. Group comparisons demonstrated that PKU children were significantly impaired on an executive function composite score; there were no group differences, however, in recognition memory. These results supported the hypothesized specific deficit in executive function. Furthermore, within the PKU group the executive function composite score was significantly negatively correlated with concurrent phenylalanine levels, even after controlling for the correlation between IQ and executive function skills. This second finding provides support for the proposed biochemical mechanism underlying the specific cognitive deficits.     

Effectiveness of a Science Agricultural Summer Experience (SASE) in Recruiting Students to Natural Resources Management

The Bureau of Labor Statistics projects an increase in Natural Resource Management (NRM) jobs within the next 10?years due to baby-boomer retirements and a 12% increase in demand for these occupations. Despite this trend, college enrollment in NRM disciplines has declined. Even more critical is the fact that the soon-to-be-majority Hispanic population is underrepresented in NRM disciplines. The goal of the present study was to determine if an in-residence, two-week, summer science program for underrepresented minorities would not only increase interest in science, actual science knowledge, and perceived science knowledge, but also have an overall impact on underrepresented minority students?? decisions to attend college, major in a scientific discipline and pursue a career in science. During a four-year period, 76 high school students participated in a Science Agricultural Summer Experience (SASE) in Northern New Mexico. A pre/post science-knowledge exam and satisfaction survey were administered to participants. We demonstrate that participants improved significantly (p?<?.05) in all areas measured. In particular, comfort with science field and lab activities, science knowledge and perceived science knowledge were enhanced after exposure to the program. Students not only found science exciting and approachable after participation, but also exhibited increased interest in pursuing a degree and career in science. Of the 76 SASE participants within graduation age (n?=?44), all graduated from high school; and 86% enrolled in college. These findings suggest that the implemented SASE initiative was effective in recruiting and increasing the confidence and abilities of underrepresented minority students in science.     

Variations on variability: effects of display composition on same–different discrimination in pigeons

Discriminating same from different multiitem arrays can be represented as a discrimination between arrays involving low variability and arrays involving high variability. In the present investigation, we first trained pigeons with the extreme values along the variability continuum (arrays containing 16 identical items vs. 16 nonidentical items), and we later tested the birds with arrays involving intermediate levels of variability; we created these testing arrays either by manipulating the combination of same and different items (mixture testing) or by changing the number of items in the same and different arrays (number testing). According to an entropy account (Young & Wasserman, Journal of Experimental Psychology: Animal Behavior Processes 23:157?C170, 1997), the particular means of changing variability should have no effect on same?Cdifferent discrimination performance: Equivalent variability should yield equivalent performance. In this critical test of an entropy account, we found that entropy could explain a large portion of our data, but not the entire collection of results.     

Mass Media

Robert C. Toll's On with the Show: The First Century of Show Business in America (New York: Oxford University Press, 1976---$19.95)

Edwin Fisher, et al., eds. The Art in Cartooning: Seventy-five Years of American Magazine Cartoons (New York : Scribner's, 1975---$14.95)

Vaughncille Molden's Telecommunications and Black Americans: A Survey of Ownership, Participation and Control (Center for Development Technology and Program in Technology and Human Affairs, Washington University, St. Louis, Mo. 63130-48.50, paper)

Working Papers in Culture and Communication (Department of Anthropology, Temple University, Philadelphia, Pa. 19122-- $2.00, paper)     

European Mass Media

John Sandford's The Mass Media of the German-Speaking Countries (London: Oswald Wolff; and Ames: Iowa State University Press, 1976---price not given, paper)

Publizistik. Vierteljahreshefte fur Kommunikationsforschung (= subtitle, meaning Quarterly for Communication Research)

Rundfunk und Fernsehen (Broadcasting and Television)

Femselsen und Bildung (Television and Education)

Communicatio Socialis

Broadcast Receiving Fees in France, by Eugene Pons (EBU Monograph No. 7, 194 pp., 1969, 20 Swiss francs or about $5.00, paper)

German Radio and Television: Organization and Economic Basis, by Hans Brack (EBU Monograph No. 6, 68 pp., 1968, 8 Sw. Fr. or about $2.00, paper)

Broadcasting in the Space Age, by Olaf Rydbeck and Edward W. Ploman (EBU Monograph No. 5, 53 pp., 8 Sw. Fr. or about $2.00, paper)

Advertising on Radio and Television (EBU Monograph No. 4, 37 pp., 1966, 5 Sw. Fr. or about $1.00)

Financial Aspects of Broadcasting, by Bruno Vasari (EBU Monograph No. 3, 45 pp., 1965, 4 Sw. Fr. or a bit less than $1.00, paper)

Television for Children and Young People, by J.D. Halloran and P.R.C. Elliott (134 pp., 1970, 10 Sw. Fr. or about $2.50, paper)

Annual Seminar for Producers and Directors of Adult Education by Television (12th Seminar, 1974, 79 pp., 5 Sw. Fr. or about $1.00)

Annual Seminar for Producers and Directors of School Television (11th Seminar, 1973, 79 pp., 5 Sw. Fr. or about $1.00, paper)

Workshops for Producers and Directors of Television Programs for Children (4th Workshop, 1974, 48 pp., 8 Sw. Fr. or about $2.00, paper)

International Forum of Light Music in Radio (1971, 1973, and 1975 editions available, 5 Sw. Fr. each or about $1.00 each, paper)

The Evolution of the EBU through its Statutes from 1950 to 1976 (EBU Monograph No. 11, 1977, 25 Sw. Fr. or something over $5.00, paper)

International Conference of States on the Protection of Phonograms (Paris: Unesco; and New York: Unipub, 1975---$34.75, paper)