Quantile estimation based on nomination sampling

Nomination sampling is a sampling process in which every observation is the maximum of a random sample from some distribution. If all samples are taken from a single underlying CDF, F, data can be viewed as consisting of pairs (X_i,K_i) where K_i is the size of sample i and, given K_i=k_i, X_i is distributed according to CDF F^ki. R.A. Boyles and F.J. Samaniego (1986) developed a nonparametric maximum-likelihood estimator of F. In the present work, their approach is extended to obtain estimates of the quantiles of F and to study the limit theory and consistency properties of these estimates. These results generalize the results of T.R. Willemain (1980), who discussed the estimation of the median of F based on nomination samples     

Spinal injuries in New Zealand rugby and rugby league--a twenty year survey

AIMS: To establish trends in frequency of serious spinal cord injuries in rugby and rugby league over a 20 year period and to elucidate patterns of injury from retrospective analysis of cases admitted to New Zealand's two spinal injuries units. METHODS: A detailed survey of unit records with follow-up of selected patients; statistical analysis of data. RESULTS: During the 20 years 1976 to 1995, 119 rugby and 22 rugby league players (total 141) were admitted to New Zealand's two spinal injuries units suffering serious spinal injuries and 47 of these became permanently confined to wheelchairs. There was a steady increase in frequency throughout the period studied. Of the injuries 83% occurred in forwards and 17% in backs. In rugby it was the scrum which produced most injuries, and in rugby league it was the tackle. The early season month of April produced most spinal injuries. In the eighteen months since intense compulsory educational programmes on safety were introduced by the New Zealand Rugby Union there have been no serious spinal cord injuries from rugby scrums. CONCLUSION: Contrary to widespread belief, there has not been a decrease in spinal cord injuries in rugby following rule changes in the mid 1980s. The information produced by this retrospective study has been an effective educational platform to make rugby and rugby league safer.     

Simulating the propagation of displacement discontinuities in a regularized strain‐softening medium

A numerical model is developed which allows the inclusion of displacement discontinuities in a strain‐softening medium, independent of the finite element mesh structure. Inelastic deformations develop in the continuum and, when a critical threshold of inelastic deformation is reached, a displacement discontinuity is inserted. Discontinuities are introduced using the partition of unity concept which allows discontinuous functions to be added to the standard finite element basis. It is shown that the introduction of displacement discontinuities at the later stages of the failure process can lead to a failure mode that is fundamentally different than that using a continuum model only. This combined continuum‐discontinuous model is better able to describe the entire failure process than a continuum or a discrete model alone and treats mode‐I and mode‐II failure in a unified fashion. Copyright © 2001 John Wiley & Sons, Ltd.     

2.75-4.75 GHz QPSK modulator with low amplitude and phase errors

A QPSK modulator with a 2.75-4.75 GHz operating frequency range is presented. The modulator is realised using a broadband power divider, microstrip-slotline-microstrip transitions and Lange couplers. Computer optimised matching circuits are used to maintain a phase error less than 5 degrees and an amplitude phase imbalance error across the band of less than 0.5 dB. The modulator is suitable for MMIC implementation.<>     

The relationship between postmortem urinary catecholamines, meat ultimate pH, and shear force in bulls and cows

We investigated the relationship between stress responsiveness and meat quality in cattle. The cattle were 16-19-month-old Mixed (n=37, 303 kg) or Non-mixed (n=23, 279 kg) Friesian bulls and Friesian cull cows (1.5-7 years) that were classified Unfinished (n=133, 195 kg) or Finished for 3 months (n=34, 252 kg). A portion of m. longissimus lumborum (LL) muscle was obtained from consecutive animals for a single days slaughter of 227 cattle processed through a hot boning plant. Catecholamines were obtained from bladder urine. Ultimate pH, lactate, glycogen, glycolytic potential and representative sarcomere lengths were determined from 20-h muscle samples. Shear force measurements were from meat aged at 15 °C for 20 and 90 h. Urinary noradrenaline was similar between Mixed (14.86 ng/μmol creatinine) and Non-mixed bulls (14.07 ng/μmol creatinine) and Finished cows (15.24 ng/μmol creatinine) and elevated in the Unfinished cows (22.28 ng/μmol creatinine). Urinary adrenaline was higher in Mixed bulls (9.5 ng/μmol creatinine) than Non-mixed bulls (5.7 ng/μmol creatinine) and higher in both Unfinished cows (16.67 ng/μmol creatinine) and Finished cows (14.19 ng/μmol creatinine). For bulls that are growing well on-farm, with a only short period of fasting prior to slaughter, pH(u) is a good predictor of meat tenderness. In this situation, stressors that lower muscle glycogen pre-slaughter can have a significant effect on meat shear force, and individual animals with elevated urinary adrenaline were the most susceptible. However, in the case of cows, adrenaline responses are not necessarily associated with glycogen depletion and pH(u) is less affected than for bulls. Furthermore, the ability of meat to tenderise fully, related to reduced proteolytic turnover, is reduced in nutritionally compromised animals such as the Unfinished cows.     

Cover Image,Volume 97, Issue 11

The cover image, by Hannah C Wells et al., is based on the Research Article Deer leather: analysis of the microstructure affecting pebble, DOI: 10.1002/jsfa.8199 .