Circular 118

A yield trial comparing 30 cultivars of potatoes (Solatium tuberosum L.) was conducted during the 1999 growing season at the University of Alaska Fairbanks, Agricultural and Forestry Experiment Station’s (AFES) Palmer Research Center, Matanuska Farm, located six miles west of Palmer, Alaska. Similar to 1998, this trial included irrigated but not irrigated treatments. Data from previous studies has documented the consistent need for irrigation as well as the magnitude of increases in yield that can be realized through irrigation

Analysis of physical-activity profiles when running with the ball in a professional soccer team

This study characterised physical demands when running with the ball in a professional soccer team and (1) determined activity profiles during match play; (2) examined effects of fatigue and (3) investigated differences according to playing position. Thirty French League 1 matches from two competitive seasons (2007-2008, 2008-2009) were analysed using multi-camera computerised tracking. Players (n=27) ran a mean total distance of 191.0±38.0 m with the ball of which 34.3% was covered at speeds >19.1 km/h, 25.6% between 14.1-19.0 km/h, 12.5% between 11.1-14.0 km/h and 27.6% at <11.0 km/h. Mean distance covered per possession was 4.2±0.7 m, speed at ball reception was 10.3±0.9 km/h while mean and peak speeds during runs were 12.9±1.0 km/h and 24.9±2.4 km/h. Mean time in possession, duration and touches per possession were 53.4±8.1 s, 1.1±0.1 s and 2.0±0.2. There were differences across playing positions for all variables (P at least 0.017 and effect size at least 0.5). Total distance run did not differ between halves but varied over the course of matches (p<0.001) decreasing just before half-time. These findings provide valuable information about the physical and technical requirements of running with the ball that could be useful in the prescription of general and individualised training programmes

Subaqueous “yardangs”: analogs for aeolian yardang evolution

Landforms, morphologically similar to aeolian yardangs but formed by erosion of bedrock by currents on an estuarine rock platform, are described for the first time. The geometries of the “yardangs” are described and related to semi-lemniscate shapes that minimize hydraulic drag. The processes of bedrock erosion by the reversing sediment-laden tidal currents are described, and a semi-quantitative model for landform evolution is proposed. The model casts doubt on the “simple” role of the maximum in the two-dimensional vertical suspended sediment flux distribution and the consequent distribution of potential kinetic energy flux in the process of shaping the rock wall facing the ebb flow. Rather, although the kinetic energy flux increases away from the bed, the sediment becomes finer and abrasion likely is insignificant compared with coarse sand abrasion lower in the profile. In addition, the vertical distribution of sediment flux is mediated by topographic forcing which raises the elevation at which bed load intersects the yardang prow. Consequent erosion leads to ebb-facing caprock collapse and yardang shortening. In contrast, the role of ebb-flow separation is paramount in mediating the abrasion process that molds the rock surface facing the flood flow. The length of yardangs is the least conservative dimension, reducing through time more rapidly than the height and width. Width is the more conservative dimension which implies that once the caprock is destroyed, scour over the obstacle is significant in reducing body height, more so than scour of the flanks which reduces width. The importance of vertical fissures in instigating the final breakdown of smaller yardangs and their extinction is noted. Similarities to aeolian yardang geometries and formation principles and processes are noted, as are the differences. The model has implications for aeolian yardang models generally

The effect of an early dismissal on player work-rate in a professional soccer match

The aim of this study was to examine the effects of an early dismissal (after 5-minutes play) on work-rate in a professional soccer match. A computerised player tracking system was used to assess the work-rates of seven players who completed the match on the team with 10 players. A minute-by-minute analysis of the remaining 91mins following the dismissal was performed for the total distance covered, the distance covered in five categories of movement intensity and the recovery time between high-intensity efforts for each player. The data were calculated for each half and for three equal intervals within each half and profiled against normative data for the same players obtained from analyses of 15 games in the same season. Following the dismissal, the players covered a greater total distance than normal (p<0.025), particularly in moderate-intensity activities (p<0.01) and had shorter recovery times between high-intensity efforts (p<0.025). In contrast, there was a significant reduction between game halves for total distance covered at both the highest (p<0.025) and lowest running intensities (p<0.01). However, there were no differences in high-intensity activities across the three intervals in the second-half. These findings suggest that in 11 v 11, players may not always utilise their full physical potential as this match illustrated an increase in overall work-rate when reduced to 10 players. However, as a team with 10 players is likely to incur higher levels of fatigue, tactical alterations may be necessary and/or players may adopt a pacing strategy to endure the remainder of the match

Resistant outlier rules and the non-Gaussian case

The techniques of exploratory data analysis include a resistant rule, based on a linear combination of quartiles, for identification of outliers. This paper shows that the substitution of the quartiles with the median leads to a better performance in the non-Gaussian case. The improvement occurs in terms of resistance and efficiency, and an outside rate that is less affected by the sample size. The paper also studies issues of practical importance in the spirit of robustness by considering moderately skewed and fat tail distributions obtatined as special cases of the Generalized Lambda Distribution.Asymptotic efficiency; Generalized Lambda Distribution; Kurtosis; Outside rate; Resistance; Skewness; Small-sample bias

Circular 58

A comparative yield trial with 44 named varieties and numbered selections of potatoes was conducted at the University of Alaska-Fairbanks, Agricultural and Forestry Experiment Station’s (AFES) Palmer Research Center during the 1986 growing season. This yield trial is the continuation of a potato variety testing program initiated in 1982. The trial again was conducted at the Matanuska Research Farm, located on Trunk Road near Palmer. Nonirrigated trials have been conducted each year beginning in 1982, but irrigated trials were not initiated until 1985. Results of previous trials are recorded in Circulars 49 and 54, available at the Agricultural and Forestry Experiment Station offices in Fairbanks and Palmer. As in past years, varieties with long production histories in Alaska (Alaska 114, Bakeking, Green Mountain, Kennebec, Superior) are included and serve as a comparative base for newly developed varieties or older varieties that in the past have escaped testing at this location. Varieties that compare favorably with the above listed standards may warrant some consideration by commercial growers. In continuance of a program that was initiated in 1985, abbreviated versions of the AFES potato yield trial were conducted at locations in various parts of the state. These off-station trials again were made possible by the willingness of cooperators to plant, tend and harvest the crop. The seven off-station sites include several where comparative testing of potato varieties has not been reported previously.Introduction -- Matanuska Farm Yield Trials: Cultural Practices - Environmental Conditions, Results, Discussion -- Trials at Other Locations in Alaska: General Procedures, Specific Site Information: Ambler, Copper Center, Delta Junction, Fairbanks, Kake, Kodiak, Noorvi

Discharge and turbidity of the regulated River Tees. Variance spectrum analysis

High suspended sediment loads may be deleterious to adult salmonids and invertebrates in gravel-bedded streams. Further, the accumulation of fine material in the interstices of the gravel may have an adverse impact on the recruitment of the young stages of salmonids. It is important therefore not only to quantify the rates and degrees of silting but also to identify sediment sources and to determine both, the frequency of sediment inputs to the system and the duration of high sediment concentrations. This report explores the application of variance spectrum analysis to the isolation of sediment periodicities. For the particular river chosen for examination the method demonstrated the essentially undisturbed nature of the catchment. The regulated river chosen for examination is the River Tees in Northern England. Variance spectrum analysis was applied to a series of over 4000 paired daily turbidity and discharge readings

Circular 49

A program of field research relating to the commercial production o f potatoes was initiated in 1982 at the University of Alaska Agricultural Experiment Station ’s research center in Palmer. T he experimental fields are located at the Matanuska Research Farm on Trunk Road near Palmer. This program is a modified continuation of a potato research program initiated more than 30 years ago by D r. C .H . Dearborn. Whereas the major emphasis of D r. Dearborn ’s potato program w as variety development and testing, the major emphasis here is study o f general cultural practices, disease development and control, and the comparative evaluation (yield trials) o f potato varieties having commercial potential. Plans call for the comparative evaluation of thirty to forty named varieties or numbered selections each year. Varieties are selected for testing on the basis o f yield potential, general quality characteristics, and disease resistance. An attempt is made to include all varieties grow n commercially in the state, newly developed varieties from breeding program s in the U .S ., Canada, and elsewhere, as well as established varieties that have yet to be thoroughly tested in this environment. Commercial varieties with locally proven “ track record s ," such as Alaska 114, Bakeking, Green Mountain, and Superior will serve as a comparative base for m ore recently introduced varieites. New varieties will be tested for 4-5 years before being dropped , kept for further study, or recommended to commercial growers. Summarized in this circular are the results o f three years o f variety trials (1982, ’83, and ’84). Also included are summaries of environmental conditions at or near the experimental test site and some detailed information about several locally grown commercial varieties.Introduction -- Weather Data Summary: 1982 -- Weather Data Summary: 1983 -- Weather Data Summary: 1984 -- Yield Data Summary -- Variety Descriptions -- See

Circular 97

A yield trial in which 43 named varieties and one numbered selection of potatoes were compared was conducted during the 1993 growing season at the University of Alaska Fairbanks, Agricultural and Forestry Experiment Station’s Palmer Research Center, Matanuska Farm, located six miles west of Palmer, Alaska.Potato Variety Performance -- Introduction -- Matanuska Farm Yield Trials: Cultural Practices and Environmental Conditions; Results and Discussion -- Trials at Other Locations in Alaska: General Procedures; Site-Specific Information; Delta Junction; Fairbanks; Homer; Kenai-Soldotna; Nom

Comment on “Football-specific fitness testing: adding value or confirming the evidence?”

The recent point–counter-point exchange arising from the article by Mendez-Villanueva and Buchheit (2013) (Football-specific fitness testing: Adding value or confirming the evidence? Journal of Sports Sciences, 31, 1503–1508) has generated an interesting debate on the real-world utility of fitness testing in professional association football (soccer). In the present authors’ opinion, this exchange could also have been placed more in the context of the physical testing and subsequent benchmark profiling of the youth player within elite academy talent identification and development processes. This point is further strengthened by the current media debate at the time of writing on the development of elite youth football players in England and the Elite Player Performance Plan or EPPP (The Premier League. (2011). Elite Player Performance Plan. London: Author) published by the English Premier League as part of a vision for the future development of youth football in the League and throughout the English professional game. The EPPP recommends the implementation of a national database to enable comparison of Academy player performances against national physical testing “benchmark” profiles. In continuing the above debate, this letter questions the real-world utility and potential pitfalls of nationwide athletic benchmark profiling programmes for elite youth football