Small Differences In Duration Research Articles

Effect of variable crop duration on grain yield of irrigated spring-wheat when flowering is synchronised

Short duration spring wheat cultivars are currently preferred for irrigated wheat production in subtropical Australia due to their high levels of lodging resistance. A study was conducted to determine whether recently developed lodging-resistant long duration cultivars could achieve increased grain yield compared to short duration cultivars in irrigated sub-tropical environments. A key aspect of the study methodology required the use of different sowing dates for each maturity group to ensure anthesis was synchronised and thus occurred during the same climatic conditions. Growth of representative cultivars in each experiment was simulated using the APSIM model to characterise each environment for the presence of water or nitrogen stress. Results of the study indicated that the long duration cultivars had an increased grain yield of 0.67 t ha−1 (9.6%) on average across the 14 agro-climatic environments compared to the short duration cultivars. The response varied between agro-climatic environments, with long duration cultivars significantly higher yielding in 70% (or ten) of the environments, no significant difference observed in three environments, and a significantly lower yield associated with long duration cultivars in one environment. The yield advantage of the long duration cultivars was greater in environments where moderate water stress was experienced, with yield differences of up to 1.5 t ha−1 observed in the most water-stressed environments. The yield advantage was less apparent in environments where low levels of water stress were experienced, and in two environments where lodging was more severe among the long duration cultivars. The relatively small difference in duration between the long and short duration cultivars in this study may not have fully exploited the potential benefits of longer duration cultivars. The results suggest that genetic improvement programs should continue to develop longer season germplasm that conveys an adaptive advantage to irrigated sub-tropical environments such as Australia, India and Mexico that experience short-term water deficits, and in which deficit irrigation is often the most profitable strategy for farmers. Additional research is necessary to determine whether ultra-long duration cultivars could further raise yield potential in sub-tropical environments if lodging could be avoided, through either genetic improvement or improved access to plant growth regulators.

Canadian Raising in Chicagoland: The production and perception of a marginal contrast

In some North American English varieties the diphthong /aɪ/ has developed a distinctively higher nucleus before voiceless consonants and also before a flapped /t/. The phenomenon is known as Canadian Raising, as it was first described for Canadian English. We report on variation in the production and perception of this distinction in a group of female and male speakers from the Chicago area. We focus on the context before flapped /t/ and /d/. The production results show that there is a significant difference in the quality of both the nucleus and the offglide between these two contexts, albeit of a smaller magnitude than the difference observed before word-final voiceless and voiced consonants. In addition, we find a small difference in duration between diphthongs in the two pre-flap contexts. In perception, our subjects were only moderately successful in recognizing words in minimal pairs containing the target diphthong preceding a flap (as in writer vs rider), although with much higher than chance accuracy. A Quadratic Discriminant Analysis model classified the stimuli with substantially greater accuracy than our subjects. We conclude that in this English variety there is a contrast between a higher diphthong [ʌi] and a lower diphthong [aɪ], but this contrast is only marginal. This study contributes to our understanding of marginal contrasts in production and perception. The understanding of these contrasts has both theoretical and practical relevance.

SURGICAL PROCEDURE FOR GROIN HERNIAS SELECTED BY THE NYHUS' CLASSIFICATION

We have made a nonrandomaized study to compare operative procedure for groin hernias including open conventional, open mesh plug, and laparoscopic mesh hernia repair by types of hernias according to the Nyhus' classification. In type-I and II hernias, there were small difference in duration of postoperative hospital stay and frequency of narcotic analgesics among three procedures. In type-III, the conventional repair required longer postoperative hospital stay and more narcotic analgesics than the mesh plug or laparoscopic technique. Each procedure has both merits and demerits. We employ surgical procedure selected by the condition of hernia and the patient's quality of life. In type-I, the conventional technique is suitable for the patients who don't require repair with prosthetic material. In type-II, the conventional procedure without prosthesis may be the preferred repair in the young patient, while the tension free repair is proper for the hernia close to type-III. The mesh plug repair that turned out good results is indicated in type-III, but for large hernias, the laparoscopic technique that uses a large mesh offers an excellent repair. In type-IV, the laparoscopic repair is appropriate for recurrent hernias after anterior approach. This approach that operative procedure is selected by the Nyhus' classification has produced good postoperative results.

Timing Functions of The Cerebellum

This study investigated the effects of different types of neurological deficits on timing functions. The performance of Parkinson, cerebellar, cortical, and peripheral neuropathy patients was compared to age-matched control subjects on two separate measures of timing functions. The first task involved the production of timed intervals in which the subjects attempted to maintain a simple rhythm. The second task measured the subjects' perceptual ability to discriminate between small differences in the duration of two intervals. The primacy of the cerebellum in timing functions was demonstrated by the finding that these were the only patients who showed a deficit in both the production and perception of timing tasks. The cerebellar group was found to have increased variability in performing rhythmic tapping and they were less accurate than the other groups in making perceptual discriminations regarding small differences in duration. Critically, this perceptual deficit appears to be specific to the perception of time since the cerebellar patients were unaffected in a control task measuring the perception of loudness. It is argued that the operation of a timing mechanism can be conceptualized as an isolable component of the motor control system. Furthermore, the results suggest that the domain of the cerebellar timing process is not limited to the motor system, but is employed by other perceptual and cognitive systems when temporally predictive computations are needed.