Kleinberg Navigation in Fractal Small World Networks

We study the Kleinberg problem of navigation in Small World networks when the underlying lattice is a fractal consisting of N>>1 nodes. Our extensive numerical simulations confirm the prediction that most efficient navigation is attained when the length r of long-range links is taken from the distribution P(r)~r^{-alpha}, where alpha=d_f, the fractal dimension of the underlying lattice. We find finite-size corrections to the exponent alpha, proportional to 1/(ln N)^2

An imaging vector magnetograph for the next solar maximum

Researchers describe the conceptual design of a new imaging vector magnetograph currently being constructed at the University of Hawaii. The instrument combines a modest solar telescope with a rotating quarter-wave plate, an acousto-optical tunable prefilter as a blocker for a servo-controlled Fabry-Perot etalon, CCD cameras, and on-line digital image processing. Its high spatial resolution (1/2 arcsec pixel size) over a large field of view (5 by 5 arcmin) will be sufficient to significantly measure, for the first time, the magnetic energy dissipated in major solar flares. Its millisecond tunability and wide spectral range (5000 to 7000 A) enable nearly simultaneous vector magnetic field measurements in the gas-pressure-dominated photosphere and magnetically-dominated chromosphere, as well as effective co-alignment with Solar-A's X ray images. Researchers expect to have the instrument in operation at Mees Solar Observatory (Haleakala) in early 1991. They have chosen to use tunable filters as wavelength-selection elements in order to emphasize the spatial relationships between magnetic field elements, and to permit construction of a compact, efficient instrument. This means that spectral information must be obtained from sequences of images, which can cause line profile distortions due to effects of atmospheric seeing

SUIZA FOODS CORPORATION: BEST MANAGEMENT STRATEGY IN THE FLUID MILK INDUSTRY

Suiza Foods has rapidly grown to become the largest company in the U.S. fluid milk industry. This teaching case is designed to familiarize students with the challenges which confront Suiza in its quest for further growth and, in turn, high profitability. Interviews with top executives describe the history of Suiza as well as the rationale behind Suiza's strategies. Information is presented on both economic and financial trends so as to allow the student to asses Suiza's past, present and future performance.Agribusiness, Livestock Production/Industries,

Investigation of prediction methods for the loads and stresses of Apollo type spacecraft parachutes. Volume 1: Loads

An analysis was conducted with the objective of upgrading and improving the loads, stress, and performance prediction methods for Apollo spacecraft parachutes. The subjects considered were: (1) methods for a new theoretical approach to the parachute opening process, (2) new experimental-analytical techniques to improve the measurement of pressures, stresses, and strains in inflight parachutes, and (3) a numerical method for analyzing the dynamical behavior of rapidly loaded pilot chute risers

Bankfull curves for the temperate rainforests in the Southern Appalachian Mountains of Western North Carolina

Bankfull hydraulic geometry relationships, also called regional curves, relate bankfull stream channel dimensions and discharge to watershed drainage area. This paper describes results of bankfull curve relationships developed for the temperate rainforests of the Southern Appalachian Mountains primarily on Western North Carolina Mountain streams in the Southeastern United States. Gauge stations for small and larger catchments were selected with a range of 10 to 50 years of continuous or peak discharge measurements, no major impoundments, no significant change in land use over the past 10 years, and impervious cover ranges of <20%. Cross-sectional and longitudinal surveys were measured at each study reach to determine channel dimension, pattern, and profile information. Log-Pearson Type III distributions were used to analyze annual peak discharge data for nine small watersheds sites gauged by the United States Department of Agriculture (USDA), Forest Service, Southern Research Station, Coweeta Hydrologic Laboratory and for eleven larger watersheds gauged by the United States Geological Survey (USGS). Power function relationships were developed using regression analyses for bankfull discharge, channel cross-sectional area, mean depth, and width as functions of watershed drainage area

Effect of Dolphin Kick Timing on Breaststroke Pullout Performance

Breaststroke pullouts are now permitted to include a dolphin kick. Two variations of the pullout are distinguished by the timing of the dolphin kick within the movement. One variation uses an early-initiation of the dolphin kick (performed before the initiation of the arm pull) while a second variation uses a late-initiation of the dolphin kick (performed at the completion of the arm pull). PURPOSE: To compare the performance of two variations of breaststroke pullouts that incorporate a dolphin kick. METHODS: Fourteen collegiate swimmers (18.9 ± 1.17 years, 73.7 ± 8.54 kg, 174.5 ± 9.88 cm) who compete in breaststroke or IM races, volunteered to participate in this study and provided informed consent prior to beginning participation. Participants completed four 45.7 m (50 yd) trials of breaststroke swimming in a 22.8 m pool. In each trial, swimming speed was increased to maximum as they approached the midpoint of the swim. After completing a turn, swimmers performed one of the two designated pullout techniques and maintained maximal effort through two complete stroke cycles. Two trials of each pullout technique were completed and filmed at 60 Hz using a calibrated underwater camera. Using 12 digitized body landmarks, a 13-segment model of the body was defined and used to compute whole body center of mass location. Two-way repeated measures ANOVA’s were used to compare the time needed to travel specified distances from either the wall or the initiation of movement. Pairwise comparisons were used to follow-up any significant main effects. RESULTS: Time to 6 m from the wall was 0.12 s (pCONCLUSION:These data suggest that the early dolphin kick variation is superior by covering distance in less time after initiation of movement and increasing the distance covered underwater